The Secondary Structure of Heated Whey Protein andIts Hydrolysates Antigenicity

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乳清分离蛋白-可溶性淀粉接枝物的制备及其理化性质

乳清分离蛋白-可溶性淀粉接枝物的制备及其理化性质罗志刚;卢静静;孙炜炜【摘要】To provide a reference on the study of protein-starch conjugate, the formation and secondary structure of whey protein isolate-soluble starch（SS） conjugate prepared by dry-heating method were investigated. The indexes of significant changes in A294 , browning intensity, free amino groups content and SDS-PAGE showed that WPI-SS conjugate was successfully prepared based on Maillard reaction under dry-heating. The results also showed that more incubation time significantly promoted glycosylation in the WPI-SS mixture. Meanwhile, the secondary structure of whey protein isolate had a considerable loss due to the covalent attachment of high molecular weight starch ; the surface hydrophobicity of whey protein was reduced.%研究了干热法处理条件下乳清分离蛋白-可溶性淀粉接枝物的制备及其二级结构分析，为蛋白质-淀粉接枝物的研究提供参考。

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Chemical Engineering Science62(2007)1948–1957/locate/cesStructure and rate of growth of whey protein deposit from in situ electrical conductivity during fouling in a plate heat exchanger Romuald Guérin,Gilles Ronse,Laurent Bouvier,Pascal Debreyne,Guillaume Delaplace∗UR638,Génie des Procédés et Technologie Alimentaires,INRA,F-59651,Villenueve d’Ascq,FranceReceived7August2006;received in revised form13December2006;accepted15December2006Available online30December2006This paper is dedicated to the memory of Dr Jean-Claude LeulietAbstractThe inﬂuences of calcium concentrations(70.88mg/l),Reynolds number(2000–5000)and temperature(60.96◦C)upon the deposit structure and the rate of growth deposition have been investigated in a plate heat exchanger.This was done from in situ measurements of the deposit electrical conductivity via implementation of stainless steel electrodes in channels combined with assessments of deposit thickness.Calcium ions affect structures of deposits and increase the rate of deposit growth upon heated surfaces.This was attributed to the formation of weaker size aggregates at higher calcium concentrations and a higher number of calcium bindings,which reinforce adhesion forces between protein aggregates.Structures and appearances of deposits also were affected byﬂow rates whatever the calcium concentrations.Deposit growth rate was enhanced by increasingﬂow rate below a critical Reynolds number comprised between3200and5000.On the contrary,above the critical Reynolds number,a limitation of the deposit and/or an escape of the deposit from the fouled layer into the coreﬂuid occurred,caused by the predominance of particle breakage on the deposit formation.Fouling tended to be reduced at higherﬂow rate.It was noteworthy that rates of growth decrease during fouling experiments which may be explained by an increase in local shear stresses leading to particle breakage.᭧2007Elsevier Ltd.All rights reserved.Keywords:Fouling;Whey protein;Calcium ions;Reynolds number;Shear stress;Deposit structure;Plate heat exchanger;Electrical conductivity1.IntroductionPlate heat exchangers(PHEs)are widely used in food indus-tries.Several advantages in using PHEs have been discussed elsewhere(Corrieu,1980;Bond,1981).The main problems en-countered by users of heat exchangers are linked to fouling,cor-rosion or mechanical resistance.Bott(1992)shows that fouling of heat exchangers,classically observed with dairy products, is in the front row of the industrial preoccupations.Fouling of heated surfaces directly contributes toward increased costs in production and energy losses,cleaning,and hinders a constant product quality and overall process efﬁciency(Yoon and Lund, 1989;Delplace et al.,1994;Jeurnink and de Kruif,1995;Visser and Jeurnink,1997).∗Corresponding author.E-mail address:delapla@lille.inra.fr(G.Delaplace).0009-2509/$-see front matter᭧2007Elsevier Ltd.All rights reserved. doi:10.1016/j.ces.2006.12.038In dairy industries,deposits consist of a layer of protein aggregates and minerals(Tissier and Lalande,1986).Among all milk proteins, -lactoglobulin has been identiﬁed as one of the major contributors to fouling as it undergoes thermal denaturation(Lalande et al.,1985;Lalande and Rene,1988; Gotham et al.,1989).Consequently,whey protein concentrate (WPC)solutions often have applied as a modelﬂuid to mimic fouling reactions during pasteurisation of milk both in the bulk and in the deposit at heat surfaces.There has been a considerable amount of work showing that fouling affects hydrodynamic and thermodynamic perfor-mances of heat exchangers.These studies,carried out with different dairy product compositions and process conditions, put forward the main parameters which interfere upon the foul-ing deposit mass(De Jong et al.,1992;Belmar-Beiny et al., 1993;Delplace et al.,1994;Delplace and Leuliet,1995;Fryer et al.,1996;Changani et al.,1997;Visser and Jeurnink,1997;R.Guérin et al./Chemical Engineering Science62(2007)1948–19571949Christian et al.,2002;Prakash et al.,2006).The main param-eters were for instance wall temperatures andﬂow rate as pro-cess parameters and ionic force,type of ions,pH and protein concentration as chemical composition parameters.All these works represent an important step forward in the generation of predictive models both on -lactoglobulin denatu-ration or global thermal performance degradation for the whole heat exchangers(Fryer and Slater,1985;De Jong et al.,1992; Delplace et al.,1994;Fryer et al.,1996;Visser and Jeurnink, 1997).Unfortunately,these models are not powerful enough to explain the distinct cleaning behaviours experimentally ob-served.For instance,Christian et al.(2002)showed that overall cleaning times and cleaning rates,under standard conditions, were dependant on the deposit composition.There is a lack of knowledge concerning the inﬂuence of deposit structure and kinetic of deposit mass upon the cleaning efﬁciency to get rid off the total mass deposit.To overcome these difﬁculties,stud-ies that report the effect of process parameters and composi-tion upon the structure of the fouled layer are required.The aim of this work was partly to contribute to thisﬁeld.In par-ticular,various controlled conditions ofﬂow rate and calcium concentration of a WPC solution in a PHE were carried out to determine the inﬂuence of these parameters upon the structure and the kinetic of fouled layers.The structure and the growth of the fouled layer were estimated in-line from in situ measurements of the electrical conductivity of the fouled deposit.This was done by the im-plementation of two opposite stainless steel electrodes in PHE channels.In the last section,the electrode system was imple-mented in various channels to determine the inﬂuence of the temperature upon the deposit.2.Materials and methods2.1.ModelﬂuidThe modelﬂuid used in this study was reconstituted from WPC75supplied by Armor Proteines(France).The compo-sition of the powder as given by the manufacturer is shown in Table1.Proteins are the main components of the WPC pow-der(76%w/w)in which -lactoglobulin and -lactalbumin represent63%(w/w)and11%(w/w),respectively.Minerals represented less than4%(w/w)of the total dry weight of the powder.To produce solutions with higher mineral concentra-tion,the powder was dispersed in controlled quality water. Water consisted of a mixture of tap water of Lille(France)and soft water using a water softener(HI-FLO1,Culligan, Purolite C100E resin,France).The calcium and sodium con-tents of tap water,determined by atomic absorption spectropho-tometry(Philips,Pye Unicam),varied in the range170–200 and44–64mg/l,respectively.The range of calcium and sodium contents of the soft water were1.0–3.0and304–341mg/l, respectively.The desired content of calcium of the fouling ﬂuid was obtained by mixing raw water,soft water and aﬁxed amount of powder(1%w/w).Water electrical conductivity var-ied from0.113to0.116S/m at20◦C for calcium concentration varying from35to55mg/l.The product electrical conductivity Table1Composition of WPC powder(Armor Protéines,France)and1.0%WPC solutionComponent WPC75powder(%w/w)1.0%WPC75solution(%w/w) Water 5.599.05Lactose100.1Lipids 3.70.037Protein760.76Casein––-lactoglobulin480.48-lactalbumin8.40.084Other19.80.198Minerals40.04Calcium0.450.007–0.00875 Sodium0.700.0277–0.0472 Potassium0.33N.D.Chloride0.40N.D. Phosphorus0.30N.D. Magnesium0.045N.D.Iron0.008N.D.Other 1.77N.D.Other0.8N.D.:Not determined.Fig.1.Schematic of the experimental setup.varied from0.142to0.146S/m at20◦C for a range of calcium of70–90mg/l.The addition of protein powder to the mixing of water modiﬁed the electrical conductivity value of20%. The pH of the modelﬂuid remained between7.3and7.7.2.2.Fouling experimentThe experimental set-up of pilot plant scale is shown in Fig.1.Although there are two heat exchangers(model V7 plates,Alfa-Laval Vicarb,France)in the setup,the fouling1950R.Guérin et al./Chemical Engineering Science 62(2007)1948–1957ELECTRICAL CONDUCTIVITY SENSOR TEMPERATURE PROBE Pi PLATE NUMBERCi RODUCT CHANNEL NUMBERHOT WATER HOT WATER Fig.2.Heating plate heat exchanger ﬂow arrangement and implementation of stainless steel electrodes inside channels.observations were focused on the second.The ﬁrst one was used only to pre-heat the model ﬂuid up to 60◦C where fouling was negligible.Water was used as the heating medium.The model ﬂuid was heated from 60to 96◦C in a countercurrent mode.The choice of temperatures was made taking into account the value of the denaturation temperature of the -lactoglobulin protein.Temperature value for the denaturation of -lactoglobulin is 74.76◦C (Matsudomi et al.,1991;Xiong,1992;Gotham et al.,1989;Liu et al.,1994).PHE setup consisted of 13plates form-ing six passes of one channel for the two sides (Fig.2).The equivalent space between two consecutive plates was 3.93mm.In order to keep the feed composition constant,the ﬂuid was not re-circulated once it was heated through PHEs.During ex-periments,the inlet temperature of hot water was adjusted to ensure a constant outlet model ﬂuid temperature close to 96◦C and a constant proﬁle of product temperature along the PHE as a function of time (i.e.,constant heat ﬂux).The ﬂuid foul-ing layer interface temperature in each channel was assumed constant during fouling runs.In the beginning,the PHE was brought to thermal equilibrium and desired process temperature using reverse osmosis (RO)water.The feed was switched from RO water to model ﬂuid and the experimental run was contin-ued for 330min.After the fouling experiment,model ﬂuid was replaced by cold RO water to bring the temperature of PHE and deposits to ambient temperature.Experiments were performed for various calcium concentrations and Reynolds numbers as shown in Table 2.Reynolds numbers were computed based on physical properties of water,assuming that the presence of 1%WPC in water does not modify them signiﬁcantly.Average Reynolds number for the clean heat exchanger was determined from the distribution of Re along the PHE (Re =2 Q/ w ).Inlet and outlet model ﬂuids and hot water temperatures were measured with platinum resistance probes (type pt100)with a precision of 0.1◦C.Bulk and wall temperatures in chan-nels were measured from J-type thermocouples with a preci-sion of 0.5◦C.Flow rates were measured using electromag-netic ﬂowmeters (Krohne IFM,Germany).All parameters were collected via a data acquisition system (Agilent Technologies 34970A,USA)with an acquisition period of 30s.2.3.Measurements of fouled layer thicknessDeposit thickness on the different plates was obtained by two ways:•Using a pneumatic lifting device of a uniaxial compres-sion machine (DY30Model,Adamel Lhomargy,TMI,USA)which allows to determine the distance between the support of the device and the upper of the fouled or cleaned plate as shown in Fig.3.The precision of the measurement was 0.01mm.The assessments were performed at nine positions on the plate surface.The average value of the deposit thick-ness was computed from the nine positions.•By weighing plates before and after fouling runs using a Mettler apparatus (PM3000,Switzerland)with a preci-sion of 0.1g.From a wet deposit density value equal to 1000kg /m 3(Lalande et al.,1985),the average deposit thick-ness upon each plate was obtained.Of course,this method assumes that the deposit occurs uniformly upon the plate surface.2.4.Electrical conductivity of the depositTwo AISI 304L stainless steel electrodes 0.015×0.01m were implemented in channels C3,C5and C6(Fig.2).Elec-trodes were connected to a commercial conditioning system (STRATOS 2402Cond,Knick,Germany).Electrodes were electrically insulated from metal plates using an insulating stick (Araldite A V138M-HV998,USA).The cell constant of the de-vice was determined with salt solutions whose electrical con-ductivity value was known with precision.The stainless steel electrodes provide an indication of the equivalent electrical resistance R eq through the channel (Fig.4).For ﬁxed operating conditions,the Kirchhoff’s rule allows decoupling the equivalent electrical resistance in terms of fouling ﬂuid electrical resistance (R p )and deposit electrical resistance (R d )as follows:R eq =R p +2R d .(1)R.Guérin et al./Chemical Engineering Science 62(2007)1948–19571951T a b l e 2S u m m a r y o f m e a s u r e d a n d c a l c u l a t e d p a r a m e t e r s d u r i n g h e a t t r a n s f e r t o s t u d y f o u l i n g b e h a v i o u r o f 1%W P C s o l u t i o nR u n M e a n R e (–)C a 2+(m g /l )N a +(m g /l )i ,p (◦C ) o ,p (◦C ) i ,h w (◦C ) o ,h w (◦C )M a s s o f d e p o s i tt =0t ft =0t f t =0t f t =0t fi n c h a n n e l 5(g )A 200072.9344.062.360.096.897.2102.5104.572.873.471.9B 200378.9303.260.059.796.596.6102.6107.771.976.0118.6C 204082.2280.061.561.397.196.3102.7107.973.479.1147.1D 204085.6277.460.461.595.896.9102.0109.271.980.4180.6E 339470.0323.663.863.995.595.7102.0107.475.080.8100.3F 322076.3472.061.361.395.795.5101.7115.973.489.1170.0G 321478.0364.962.662.295.095.0100.0112.374.083.9201.2H 323286.5331.262.763.694.694.6101.4121.773.293.2240.6I 493874.6329.060.861.495.495.2103.4110.974.383.490.2J 492077.4303.061.360.896.296.0103.1113.574.084.994.2K 494277.8340.063.263.995.495.1103.0111.875.286.8116.6L 492687.4306.061.261.495.995.7103.5121.374.393.3190.5R u n¯e d (M D -5)(m m )¯e d (U C M )(m m )w *(◦C ) b (◦C ) e q *(S /m ) p a t b (S /m ) p a t 100◦C (S /m ) d *a t w (S /m )d *a t 100◦C (S /m )k ×104(S /m m i n )A 0.480.4097.991.10.3030.3600.3880.2080.2101.90B 0.800.61101.990.60.3030.3730.4030.2630.2612.33C 0.980.92102.491.60.3070.3710.3980.2850.2832.82D 1.201.16105.490.10.2970.3720.4040.2750.2703.57E 0.670.69103.689.70.2480.3610.3940.1700.1673.96F 1.201.28112.289.70.2840.4720.5040.2510.2408.19G 1.341.42108.889.30.2320.3750.4090.2240.2166.50H 1.601.55118.789.80.3320.4770.5090.3370.3206.88I 0.600.59105.289.80.2460.3910.4230.1470.1425.67J 0.630.63108.590.10.2250.3600.3920.1410.1335.60K 0.780.75106.889.50.2130.3690.4020.1510.1454.75L 1.271.37121.189.80.2730.3790.4110.2280.2096.70p , d a n d e q :f o u l i n g p r o d u c t ,d e p o s i t a n d e q u i v a l e n t e l e c t r i c a l c o n d u c t i v i t y ,r e s p e c t i v e l y ; i ,p a n d o ,p :i n l e t a n d o u t l e t t e m p e r a t u r e o f t h e p r o d u c t ; i ,h w a n d o ,h w :i n l e t a n d o u t l e t t e m p e r a t u r e o f t h e h o t w a t e r ; w a n d b :w a l l a n d b u l k t e m p e r a t u r e i n c h a n n e l 5;¯ed (U C M ):a ve r a g e d e p o s i t t h i c k n e s sf r o m t h e u n i a x i a l c o m p r e s s i o n m a c h i n e ;e d (M D -5):d e p o s i t t h i c k n e s s f r o m m a s s d e p o s i t i n c h a n n e l 5;k :r a t e o f c h a ng e o f th e e q ui v a l e n t e l e c t r i c a l c o n d u c t i v i t y .∗A t330m i n .1952R.Guérin et al./Chemical Engineering Science 62(2007)1948–1957Based on the general relationship linking the electrical resis-tance to the electrical conductivity for a pair of electrodes [ =e E /(AR)with e E the length between the electrodes,A the cross-section and R the electrical resistance]and assuming that (i)the cross-section A is a constant value and (ii)the space of the ﬂuid ﬂow (e ﬂ)is deﬁned as the difference between thespace0.000 N0.005 N e 10.000 N0.005 N e 2Fouling layerStainless steel plateacbdFig.3.The thickness measurement technique using a pneumatic lifting device of a uniaxial compression machine (DY30Model,Adamel Lhomargy,TMI,USA).P 8P 9Isolating materia l Stainless steel electrodes Fluid flow Fouling layer R eqR dR dRp ABFlow directioneEFig.4.Schematic of the fouling layer and equivalent electric resistance diagram.separating the two electrodes (e E )minus the total deposit thick-ness (2e d )(Eq.(2)),the deposit electrical conductivity (DEC, d )can be expressed as a function of model ﬂuid ( p )and equivalent ( eq )electrical conductivities as shown in Eq.(3).e ﬂ=e E −2e d ,(2)d (t =t f )=e E2e d (t =t f ) 1eq (t =tf )−1p+1p−1.(3)At the beginning of the fouling experiment (i.e.,clean PHE),the value of the equivalent electrical conductivity,measured by the device,corresponded to the electrical conductivity of the model ﬂuid ( p )at the product temperature.The electrical con-ductivity of the model ﬂuid was invariant during fouling runs since the inlet temperature of hot water was adjusted to ensure a constant product temperature inside channels as a function of time.At the end of fouling runs (i.e.,fouled plates,t =t f )the deposit thickness was measured and the measurement of the equivalent electrical conductivity allowed to obtain the electri-cal conductivity of the deposit.In order to compare electrical conductivity values of each run,all conductivities were deter-mined at 100◦C as follows (Ayadi,2005): d(100◦C )= d( w )+0.0009×(100− w ), p(100◦C )= p( b )+0.0032×(100− b ),(4)where d(100◦C )represents the DEC value at 100◦C, d( w )is the DEC determined from Eq.(3)at the end wall tempera-ture w , p(100◦C )is the electrical conductivity of the fouling product at 100◦C, p( b )represents the value of the electrical conductivity of the product at the bulk temperature b .Considering a deposit temperature nearly constant and an invariant viscosity value for the product,the only parametersR.Guérin et al./Chemical Engineering Science 62(2007)1948–195719530.20.220.240.260.280.30.320.340.360.380.4Time, (min )E q u i v a l e n t e l e c t r i c a l c o n d u c t i v i t y , (S m -1)Fig.5.Equivalent electrical conductivity during fouling run using 1.0%WPC solution with calcium concentration 78.0mg /l at Re =3200.which affect DEC values are mobility and concentration of ions (Benoıˆt and Deransart,1976).However,considering a poor mobility and diffusion of ions from the bulk ﬂuid through the fouled layers due to protein networks,the DEC values are affected in the majority by the concentration of ions embedded inside the protein structure.Thus,these values constitute a good indicator of the deposit structure.3.Results and discussion3.1.Effect of calcium content on foulingTypical equivalent electrical conductivity change as a func-tion of time,measured in-line from the electrodes in the ﬁfth channel,is illustrated in Fig.5.After the switch from RO water to fouling ﬂuid,the equivalent electrical conductivity reaches a maximum value at t =15min.This value corresponds to the electrical conductivity of the product at the bulk temperature.Data reported in Table 2show that product electrical conduc-tivity values at 100◦C are little affected by the modiﬁcation of the ionic concentration (i.e.,calcium and sodium in the tested range of concentration)of the solution.At the beginning of fouling stages,very slow decreases in equivalent electrical conductivity are recorded with an initial rate k ∗(Fig.5).This region may be attributed to a homogeneous thin layer of irreversibly adsorbed individual protein molecules on clean metal surfaces (Arnebrant et al.,1985;Visser and Jeurnink,1997).Tissier and Lalande (1986)showed that this sublayer had a thickness of 0.02 m after only few minutes of contact;0.4and 1 m after 10and 30min of fouling run.This weak thickness may explain the slight decrease of the slope between t =15and 30min.The slightly decreasing slope (k ∗)indicates that the fouling mechanism starts immediately when fouling product is present in the heating zone,for a temperature higher than unfolding temperature of -lactoglobulin.After this period,the equivalent electrical conductivity decreases24681060657075808590Calcium content, (mg/l)k x 104, (S .m -1.m i n -1)parison of rates of deposit growth (k )as a function of calcium concentration in WPC solution for Re =2000,3200and 5000.(The trend lines represent the curve ﬁt of data .)linearly with time.The rate of electrical conductivity changes k is relatively high (Fig.5).The second decrease in eq may be attributed to the growth and structure changes of fouled layers.Indeed,whatever the Reynolds number,it is observed that the rate of electrical conductivity changes k rises with in-creasing calcium concentrations (Fig.6).This observation is in agreement with Li et al.(1994)observing that calcium induces conformational changes of the -lactoglobulin,facilitating the protein denaturation,but also increases the kinetic of the aggregate formation.A small change in the calcium concen-tration has an important impact upon the kinetic parameter k ,i.e.,the formation of the fouled layer.Fig.7a illustrates the electrical conductivity values of the fouled layer (DEC)obtained at a wall temperature of 100◦C in the ﬁfth channel for varying calcium concentrations at three Reynolds numbers.Whatever the Reynolds number,the DEC increases with the calcium concentration.Considering a low mobility of ions inside the deposit due to protein networks and a constant temperature in C5,this indicates that the DEC1954R.Guérin et al./Chemical Engineering Science 62(2007)1948–19570.10.20.30.4Calcium concentration,(mg.l -1)E l e c t r i c a l c o n d u c t i v i t y o f t h e d e p o s i t , (S .m -1)00.20.40.60.811.21.41.61.8Calcium concentration, (mg.l -1)F o u l e d l a y e r t h i c k n e s s e d , (m m )05001000150020002500300035004000Calcium content, (mg/l)A m o u n t o f d e p o s i t i n c h a n n e l 5, (g /m 2)parison of (a)deposit electrical conductivity at 100◦C,(b)fouled layer deposit and (c)amount of deposit in channel 5after 5.5h of heat transfer in PHE as a function of calcium concentration in WPC solution for Re =2000,3200and 5000.(The trend lines represent the curve ﬁt of data.)is affected by the deposit thickness and its structure which depends on the calcium concentration (Fig.7b).A small change in the calcium concentration has an important impact upon the fouling behaviour.Figs.6and 7indicate that calcium ions (i)are essential in the growth of fouled layers as suggested by Xiong (1992)since amounts of deposit increase with calcium concentration (Fig.7c),(ii)modify the rate of protein aggregation and (iii)lead to a greater cohesion between protein aggregates modify-ing the deposit structure.Indeed,visual analysis of the deposit after fouling runs at Re 3200using 1.0%WPC solutions revealed that fouled layers formed with low calcium content(78mg/l)have a spongy and soft texture whereas deposits formed at higher calcium content (86.5mg/l)are denser and elastic.This observation is in agreement with Pappas and Rothwell (1991)who showed that -lactoglobulin completely aggregated to form compact structures when heated with cal-cium.Simmons et al.(2007)also showed that increasing the levels of calcium had a dramatic effect on the size of the aggre-gates produced,which decreased with increasing mineral con-centration.An explanation for the difference in structure and kinetic is that calcium ions,essentially present in the deposit solid (Tissier and Lalande,1986),lead to lower size aggregates in the range of calcium concentration (70–88mg/l)and favour the growth of fouled layers by formation of bridges between adsorbed proteins and the protein aggregates formed in the bulk (Fig.8).Bridges may be formed via carboxyl groups of amino acids of -lactoglobulin as suggested by Xiong (1992).In-creasing the level of calcium would lead in a higher number of bridges resulting in a bigger stabilisation of protein aggregates as interpreted by Dauﬁn et al.(1987)and Xiong (1992),forming a narrow network which embed other ions present in the solution (i.e.,sodium,magnesium,phosphate,calcium,…),and reinforce the adhesion forces between proteins.3.2.Effect of hydrodynamics conditions on foulingFig.5shows that rates of equivalent electrical conductivity changes are not constant as function of time since the slope of equivalent electrical conductivity decreased after t =180min.This slope modiﬁcation in eq may be due to a decrease of the aggregate deposit and/or an escape of the deposit from the fouled layer into the core ﬂuid caused by particle breakage.This can be a consequence of an additional local shear stress as deposit thickness evolved (Fig.9).Indeed,shear stress in a channel is a function of channel section which is reduced with the growing fouled layer [ = .¯u. /(2(e E −2e d ))].This conﬁrms the assumption of Kern and Seaton (1959)who were the ﬁrst to underline that the formation of a fouled layer is a consequence of the rate of aggregate entry and the rate at which they escape.Fig.10illustrates the evolution of the kinetic parameter k during fouling with a 1.0%WPC solution at calcium concen-tration of 78mg /l as a function of Reynolds number.The in-crease of k between Re 2000and 3200can be explained by a weaker size of aggregates at higher shear rate for a ﬁxed tem-perature (Simmons et al.,2007)favouring the growth of the deposit and resulting in a different deposit structures (Fig.8).Deposit masses in channel 5conﬁrm this trend namely for a ﬁxed calcium concentration,the amount of deposit in C5in-creases between Re 2000and 3200(Fig.7c).Nevertheless,the k parameter decreases between Re 3200and 5000at a ﬁxed calcium concentration.Thus,the decrease of the rate of deposit is due to the increase of Reynolds number which may limit the deposit,compact the structure upon the heated surface and increase the rate of particle breakage.Visual analysis of the appearance of the deposit as a function of Reynolds number conﬁrm the trends.Deposit formed after fouling with a calcium concentration close to 78mg /l at Re 2000has a granular aspectR.Guérin et al./Chemical Engineering Science 62(2007)1948–19571955Adsorbed protein AggregatesStainless steel electrodes Stainless steel plate With lower calcium concentraionEmbedded ionsCalcium bindingsWith higher calcium concentraionFig.8.Schematic illustration of the proposed formation of the deposit with lower and higher calcium concentrations of the WPC solution.0.20.40.60.811.21.47076.37886.5Calcium concentration, (mg/l)L o c a l s h e a r s t r e s s , (P a )20406080100120140160180200Shear stress for fouled channel (C5)Shear stress for cleaned channel (C5)Increase of shear stressI n c r e a s e o f s h e a r s t r e s s , (%)Fig.9.Increase in shear stresses due to fouled layer growth as a function of calcium concentrations in 1.0%WPC solutions at Re =3200.probably due to higher size aggregates whereas deposit formed at Re 3200appears more denser (i.e.,lower aggregates size).Finally,the deposit obtained after fouling at Re 5000appears more smooth and compact which may be the consequence of the increase of the local shear stress (Fig.9).Another way to underline the inﬂuence of shear stress upon the structure of the deposit is the measurement of the electri-cal conductivity of deposits according to Reynolds numbers for a ﬁxed calcium content and temperature (Fig.7a–c).Fig.7a shows that DEC values are similar at Re 2000and 3200while amounts of deposit in C5,and so the thickness of the deposit (Figs.7b and c),are completely different with a scatter close to 35%.In the same order,amounts of deposit in C5are similar for Re 2000and 5000while the correspondingvalues of DEC1234567200032005000Reynolds number, (-)k x 104, (S m -1 m i n -1)Fig.10.Rates of deposit growth (k )as a function of Reynolds number during fouling runs with a 1.0%WPC solution with calcium concentration comprised between 76.0and 78.0mg /l.differ each other.Moreover,for a ﬁxed calcium concentration,DEC values increase with a variation of Reynolds number from 2000to 3200while a decrease in DEC values can be observed above a critical Reynolds number,which could be comprised between 3200and 5000.Since calcium concentration and tem-perature are invariant and considering a poor mobility of ions due to protein networks,differences in the structure and/or the composition of the deposit can be explained by DEC variations.This indicates that shear stress has a dramatic effect upon the structure and the appearance of the deposit whatever the cal-cium concentrations.The differences in the structure of these。

专业英语

questions
How
do you distinguish steel from cast iron? How do you distinguish low alloy steel from high alloy steel?
1.1.1 Iron and Steel
The earth contains a large number of metals which are useful to man. One of the most important of these is iron. Modern industry needs considerable quantities of this metal, either in the form of iron or in the form of steel.
Mechanical Engineering materials
Organic polymer materials Inorganic non-metallic materials
plastic rubber Synthetic Fibers Traditional ceramics Special Ceramics Metal Matrix Composites
1.1.1 Iron and Steel
The ore becomes molten, and its oxides combine with carbon from the coke. The non-metallic constituents of the ore combine with the limestone to form a liquid slag. This floats on top of the molten iron, and passed out of the furnace through a tap. The metal which remains is pig iron.

Should_We_Help_Stranger

Helping oters has always been considered a treasured virtue of human,not only because we need help from others throughout all our life,but also because it brings us tremendous happines。

Whereas,some consider that helping others can sometimes put us to trouble for the reason that there are cheats who take advantage of our sympathy,and sometimes we are not able to provide the help needed.Whatever we are faced with,we should still try our best to render help.On the one hand,everyone needs help from others。

We should help people as happiness, especially when we are now high school student we should always lend a hand to those in need.No matter when one travels to others places or stays at home，it is hard to imagine how a man can live without the help of strangers，because nearly everything he uses is made by others。

豆腐制作流程英语作文

豆腐制作流程英语作文Title: The Process of Tofu Production。

Tofu, a staple in many Asian cuisines, is a versatile and nutritious food made from soybeans. The production process involves several steps, each crucial in yielding high-quality tofu. Here, we delve into the detailed process of tofu production.Step 1: Selecting High-Quality Soybeans。

The process begins with the selection of premium-quality soybeans. These soybeans must be free from impurities and of uniform size. Quality control at this stage ensures the final product's taste and texture.Step 2: Cleaning and Soaking。

The selected soybeans undergo thorough cleaning to remove dirt, debris, and any contaminants. Once cleaned,the soybeans are soaked in water for several hours. Soaking serves multiple purposes, including softening the beans for easier grinding and initiating the germination process, which enhances nutritional value.Step 3: Grinding。

FTIR分析乳清分离蛋白-葡聚糖接枝物的结构变化 - 副本

1 材料与方法
nm 处均吸收溶液于蒸馏水中透析 24 h（4 ℃），所得透析液冻干后即为纯化的接枝物样品[8]。
1.1 材料与仪器
1.2.5 红外光谱（FT-IR）测定及图谱处理
准确称取一定量纯化后的接枝物样品，加入适量
乳清分离蛋白（蛋白质含量>95%），美国 Hilmar 的溴化钾，用研磨研成均匀的粉末，压成薄片，在恒
目前，常用的蛋白质空间结构检测方法中，X-射线晶体衍射是确定蛋白质构象最准确的方法，但它需要高质量的单晶样品，对结构复杂、柔性的大分子蛋白质来说，得到所需的晶体结构较为困难。核磁共振技术可测定蛋白质在溶液中的构象，但仅限于测定小分子的蛋白质，且对样品的需求量大、纯度要求高，
89
现代食品科技
剂于试管中，分别注入 200 μL 蒸馏水和样品液，混合
拟合等计算机辅助解析方法对酰胺Ⅰ带处理，可以给均匀后于 35 ℃水浴锅中保温 2 min，迅速测定 340 nm
出蛋白质二级结构的定性定量信息，使得红外光谱成处吸光值，两者之差△A 即为样品净吸光值。以赖氨
为一个颇有发展前景的研究领域。当蛋白质和糖发生酸作出标准曲线，根据 ΔA 计算样品中自由氨基的含
红外光谱为主要手段，对比分析了接枝反应前后乳清上柱层析（柱长 90 cm；柱直径 1 cm；洗脱流速 0.3
分离蛋白二级结构的变化，以期为蛋白质-糖接枝改性 mL/min），洗脱液为 100 mmol/L 的 Tris-HCl 缓冲溶液
的理论研究提供参考。
（pH 7.6，含 200 mmol/L NaCl），收集 280 nm 及 420
中较为准确。作为化合物鉴定和结构分析的常用手段，光度[7]。
傅里叶变换红外光谱（简称 FT-IR）独特之处在于它 1.2.3 游离氨基含量的测定

关于奶酪的英语作文

The Charms of Cheese: A Delicious Journey Cheese, a delectable dairy product, has been a part of human cuisine for centuries, enchanting taste buds with its rich flavor and diverse textures. Its history dates back to ancient times, where it was first discovered by nomadic tribes who stored milk in animal stomachs and found that it transformed into a delectable, curdled substance. Over the years, cheese has evolved into a global phenomenon, with hundreds of varieties produced across the globe, each carrying the unique flavors and traditions of its region. The charm of cheese lies in its versatility and adaptability. It can be enjoyed as a standalone snack, spread on bread, or melted into sauces and dishes. From the creamy Brie to the sharp Parmesan, each type of cheese offers a unique experience, satisfying different palates and occasions. Whether it's a casual afternoon tea or a formal dinner party, cheese always finds a place on the table, adding a touch of elegance and sophistication to any meal.The making of cheese is an intricate process that requires precision and patience. It begins with theselection of milk, which can come from cows, goats, sheep, or even buffaloes. The milk is then heated and enzymes are added to separate the curds from the whey. The curds are then shaped, pressed, and aged, undergoing a transformation that gives cheese its characteristic flavor and texture. Each step of the process requires meticulous care and attention, resulting in a product that is not onlydelicious but also nutritious.The nutritional value of cheese is also impressive. It is a rich source of calcium, protein, and essential nutrients like phosphorus and vitamin D. These nutrients are essential for maintaining good health and promoting bone strength. Cheese is also a good source of probiotics, which help maintain a healthy gut microbiome and boost the immune system.In conclusion, cheese is a culinary masterpiece that has captivated the hearts and taste buds of people across the globe. Its diverse flavors, textures, and nutritional benefits make it a staple in many diets. Whether you enjoy it as a snack, a part of a meal, or as an ingredient in cooking, cheese adds a unique and delicious touch to anyculinary experience. So, let's celebrate the charms of cheese and enjoy its rich flavors on our delicious journey! **奶酪的魅力：美味之旅**奶酪，这一美味的乳制品，几个世纪以来一直是人类饮食的一部分，以其丰富的口感和多样的质地迷倒了无数味蕾。

2024届高考英语一轮总复习选择性必修第二册Unit1ScienceandScientists单元主

UNIT 1 单元主题训练Ⅰ.阅读理解AWith outbreaks of infectious(感染性的) diseases making headlines around the world, scientists are under pressure to understand the drivers that influence the transmission of pathogens (病菌的传播) in order to better predict and control disease outbreaks.In the wilds of Botswana, a pathogen called M. mungi has a different way of infecting the banded mongoose (a small furry animal that kills snakes and rats). The pathogen spreads from animal to animal through scent(气味) marks. “Scent marks are deposited into the environment and contain smell signals that convey information from one mongoose to another，” explained Kathleen Alexander, a wildlife biologist, who led the new study.To conduct their experiment, Alexander and Carole Anne Nichols monitored the movements and communication of about 500 banded mongooses in protected park landscapes, urban environments, and other places with varying characteristics in Botswana. In this way, researchers were able to gain insight into the manner in which land type and animal behaviour interact to influence the spread of the pathogen. The result was a comprehensive data set of mongoose behavioural interactions across a range of landscape types.In high-traffic, predator-rich (食肉动物多的) environments, such as urban centres or national parks, the mongooses stayed constantly alerted(警觉的), devoting their energy to scanning the surrounding environment and preparing themselves for escaping. This super awareness likely kept them safe from danger, but it also greatly curtailed their contact with others, reducing the possibility that M. mungi would spread. “If you're running from a predator, you're not stopping to leave a message for other animals，” Nichols says. “You're running for your life.”But the opposite was true at tourism cabins, where predators are scarce and food, which is often left by human hands, is easy to find. Here, the mongooses spent a good amount of time marking scent, creating a lot of opportunities for the pathogen to spread.Previous studies by Alexander have pulled back the mask on how animal behaviour shapes the spread of disease. These new findings, however, add another layer of difference to the spread of disease, stressing the role of environments.语篇解读：本文是一篇说明文。

Performance 93 4-Way Multipoise 两阶段蒸汽炉说明书

Product Data4-Way Multipoise Design Array Allows More Applications . . .The Performance™ 93 is a must foryour product line. This high-efficiencyfurnace allows more applications withits reliable 4-way multipoise design.The Performance™ 93 is available in 6heat/airflow combinations and with the4-way multipoise design can beinstalled in upflow, downflow, orhorizontal positions. The furnace isfactory configured for upflowapplication. The versatility of thisfurnace is further enhanced by its dualventing capability. The Performance™93 can be installed as 1-pipe/Non-Directvent or 2-pipe/Direct Vent.This versatile unit utilizes hot surfaceignition (HSI) which ignites the burnersdirectly. HSI eliminates gas waste thattypical continuous-pilot designs canbring. Hot surface ignition providesreliable start-up and operation.Take a look at the control center onthe Performance™ 93. Control ofignition, inducer, and blower operationis all handled in 1 central printed circuitboard. The status indicator on thecontrol signals when an event hasoccurred and identifies where the eventis. This, along with the component testfeature, makes the Performance™ 93one of the easiest gas furnaces totroubleshoot.A unique feature of this unit is thepatented polypropylene-laminatedheat exchanger. This secondary heatexchanger ensures that all available heatis properly transferred to the airstreamand throughout the home. Using theexclusive flow-through design, thesecondary heat exchanger reduces thepressure drop in the furnace which leadsto lower electrical usage, an importantpart of this unit’s efficiency.58 When we put it all together, thePerformance™ 93 combines quality and design to bring high efficiency and comfort. You will enjoy the versatility and ease of installation of this unit. The Performance™ 93 is equipped for either left- or right-side connections. Blower speeds are easily adjustable with speed-taps conveniently located on the control center. A more efficient combustion inducer allows for more use of 2-in. vent and combustion-air piping, keeping installation costs low.As with other Carrier furnaces, this model is designed to work as a part of the total home comfort system which includes elements for cooling, air cleaning, humidification, ventilation, and zoning.THE PERFORMANCE™ 93 FEATURES/BENEFITSComfortHeat™ Technology —The Performance™ 93 has a 2-stage gas valve to vary the amount of gas being used from low-heat to high-heat stage. The low-stage operation allows longer running periods, which helps maintain your most comfortable temperature, prevents drafts, reduces noise, and enhances the air quality of your home. During the extreme cold, the high-heat levels will run to ensure that you are still comfortable.Primary Heat Exchanger & Serpentuff™ Secondary Heat Exchanger — The primary heat exchanger is corrosion resistant and maintains a proven track record for long-term reliability and high-efficiency performance. The secondary heat exchanger is built with a patented lamination process that bonds acorrosion-proof lining of polypropylene to a heavy, galvanized steel shell. The unique secondary clamshell designallows wider spacing between cells for reduced air resistance through the furnace, reduced load on the blower motor, and reduced need for cleaning. Power Heat™ Igniter — Carrier’s unique SiN igniter is not only physically robust but it is also electrically robust. It is capable of running at line voltage and does not require complex voltageregulators as do other brands. This unique feature further enhances the reliability of Performance™ 93 gas furnace and continues Carrier’s tradition oftechnology leadership and innovation in providing a reliable and durable product. ComfortFan™ — Improves comfort all year long by allowing the homeowner to select different fanspeeds during continuous fan operation to achieve more or less airflow. This is done right at the thermostat. SmartEvap™ — This feature allows your system to reduce summer time humidity levels by nearly 10% over standard systems.Media Filter Cabinet — Enhanced indoor air quality in your home is made easier with our media filter cabinet—a standard accessory on all furnaces. When installed as a part of your system, this cabinet allows for an easy and convenient addition of a Carrier high-efficiency air filter.Adaptive Logic Control Board — This self-adjusting control board contains a microprocessor which automatically calculates the precise amount of time your furnace should run and whether it should run in low-heat or high-heat operation to obtain the best comfort and energy efficiency. This control board also includes an extensivetroubleshooting and component test sequence that can monitor your heating system to ensure that it is operating properly.4-Way Multipoise Design — Allows the Performance™ 93 to be installed in an upflow, downflow, or horizontal orientation. Factory configured for upflow applications with only simple drain connection changes required for conversion to downflow or horizontal. Direct or Non-Direct Venting — The Performance™ 93 can be installed as a 1 pipe/Non-Direct vent or 2 pipe/Direct vent furnace. This provides added flexibility to meet diverse installation needs.Two-Speed Inducer Motor — This motor works with the inducer fan to optimize combustion efficiency and exhaust the flue gases out of the house. The motor has two speeds and anincorporated fan to keep the motor cool while reducing sound.Permanent split capacitor (PSC) Blower Motor — The Performance™ 93 has a PSC blower motor that has several preselected fixed speeds which can be customized to duct workinstallation requirements. The motor has a wide application of use, a basic control scheme, and is extremely reliable. Full Cabinet Insulation — This insulation completely surrounds the internal furnace casing allowing for reduced and dampened sounds and maintained efficiencies.Soft Motor Mounts— These motor mounts help to absorb shock, decrease the vibration of the motor, and minimize noise.58MTB3458Model number nomenclature58MTB060Deluxe 4-Way Multipoise 2-Stage Direct -Vent (2-Pipe) and Non-Direct Vent (1-Pipe) Condensing Gas FurnaceInput Rates (Low/High)060 — 39,000/60,000 Btuh 080 — 52,000/80,000 Btuh 100 — 65,000/100,000 Btuh 120 — 78,000/120,000 BtuhF10012Cooling Airflow(Nominal 400 CFM per 12,000 Btuh Cooling)12 — 1200 CFM 16 — 1600 CFM 20 — 2000 CFMSeriesMedia Filter Cabinet includedREGISTERED QUALITY SYSTEMCONSERVATION SERVICES PROGRAM STANDARDS Before purchasing this appliance, read important energy cost and efficiency information available from your retailer.As an ENERGY STAR ® Partner, Carrier Corporation has determined that this product meets the ENERGY STAR ®guidelines for energy efficiency.These products are engineered andmanufactured under an ISO 9001 registered quality system.58MTBPSC—Permanent Split Capacitor5658 Carrier accessories*58MTB7858Dimensions58MTB9105858MTBPerformance data*Capacity and AFUE in accordance with U.S. Government DOE test procedures.†Gas input ratings are certified for elevations to 2000 ft. For elevations above 2000 ft, reduce ratings 2% for each 1000 ft above sea level. In Can-ada, derate the unit 5% for elevations 2000 to 4500 ft above sea level.‡•Airflow shown is for bottom only return-air supply with factory supplied 1-in. washable filter(s). •For air delivery above 1800 CFM, see Air Delivery table for other options.•An airflow reduction of up to 7% may occur when using the factory-specified 4 5/16-inch wide, high efficiency media filter.•For best furnace efficiency when using the 4 5/16-inch wide media filter, adjust the blower speed tap to near the mid-point of the rise range.ICS—Isolated Combustion System58AIR DELIVERY—CFM (With Filter)**•Airflow shown is with factory supplied 1-in. washable filter.• A filter is required for each return air opening.•An airflow reduction of up to 7% may occur when using the factory-specified 4-5/16-inch wide, high efficiency media filter.•For best furnace efficiency when using the 4 5/16-inch wide media filter, adjust blower speed tap to near the mid-point of the rise range.•For horizontal and downflow applications, use “1 side or bottom” or “bottom only” as airflow reference.58Combustion-air and vent piping for Direct Vent (2-Pipe) and Non-Direct Vent (1-Pipe) Applications58MTBCombustion-air and vent piping for Direct Vent (2-Pipe) and Non-Direct Vent (1-Pipe) Applications58Combustion-air and vent piping for Direct Vent (2-Pipe) and Non-Direct Vent (1-Pipe) Applications58MTBCombustion-air and vent piping for Direct Vent (2-Pipe) and Non-Direct Vent (1-Pipe) ApplicationsMAXIMUM ALLOWABLE EXPOSED VENT PIPE LENGTH (FT) WITH AND WITHOUT INSULATIONIN WINTER DESIGN TEMPERATURE AMBIENT **Pipe length (ft) speciﬁed for maximum pipe lengths located in unconditioned spaces. Pipes located in unconditioned space cannot exceed total allowable pipe length as speciﬁed in T able 6.†Insulation thickness based on R value of 3.5 per inch.58*Permissible limits of the voltage range at which unit will operate satisfactorily.†Unit ampacity =125% of largest operating component’s full load amps plus 100% of all other potential operating components ’ (EAC, humidifier, etc.) full load amps.‡Length is as measured 1 way along wire path between unit and service panel for maximum 2% voltage drop.**Time-delay type is recommended.Typical wiring schematic—1-Stage ThermostatTypical wiring schematic—2-Stage Thermostat58MTBTypical installations5821Copyright 2009 Carrier Corp. • 7310 W. Morris St. • Indianapolis, IN 46231Printed in U.S.A .edition date: 09/09Manufacturer reserves the right to change, at any time, specifications or designs without notice and obligations Catalog No: 58MTB-2PD Replaces: 58MTB-1PD Rev.A GENERALSystem DescriptionFurnish a _________________ (4-way multipoise) dual ca-pacity gas-fired condensing furnace for use with natural gas orpropane (factory authorized conversion kit required for pro-pane); furnish cold air return plenum; furnish external medialcabinet for use with accessory media filter or standard filter.Quality AssuranceUnit will be designed, tested and constructed to the currentANSI Z 21.47/CSA 2.3 design standard for gas-fired centralfurnaces.Unit will be 3rd party certified by CSA to the current ANSI Z21.47/CSA 2.3 design standard for gas-fired central furnaces.Unit will carry the CSA Blue Star® and Blue Flame® labels.Unit efficiency testing will be performed per the current DOEtest procedure as listed in the Federal Register.Unit will be certified for capacity and efficiency and listed inthe latest GAMA Consumer’s Directory of Certified EfficiencyRatings.Unit will carry the current Federal Trade Commission EnergyGuide efficiency label.Delivery, Storage, and HandlingUnit will be shipped as single package only and is stored andhandled per unit manufacturer’s recommendations.Warranty (for inclusion by specifying engineer)U.S. and Canada only. Warranty certificate available uponrequest.PRODUCTSEquipmentComponents shall include: slow-opening dual rate gas valve toreduce ignition noise, regulate gas flow, with electric switch gasshut-off; flame proving sensor, hot surface igniter, pressureswitch assembly verifies inducer operation; flame rolloutswitch, drain tubing and installed condensate drain trap, blowerand inducer assembly, 40va transformer; low-voltage (heating)(heating/cooling) thermostat.Blower Wheel and Blower MotorGalvanized blower wheel shall be centrifugal type, staticallyand dynamically balanced. Blower motor of PSC type shall bepermanently lubricated with sealed bearings, of _____ hp, andshall be multiple-speed direct drive. Blower motor shall be softmounted to the blower scroll to reduce vibration transmission.FiltersFurnace shall have reusable-type filters. Filter shall be ______in (x) ______in. An accessory high efficiency Media Filter isavailable as an option _____________Media Filter.CasingCasing shall be of .030 in. thickness minimum, pre-painted gal-vanized steel.Two Speed Inducer Motor Two Speed Inducer motor shall be soft mounted to reduce vi-bration transmission.Primary Heat Exchangers Primary Heat exchangers shall be 3-Pass 20 gauge corrosion re-sistant aluminized steel of fold-and-crimp sectional design, which operates under negative pressure. Secondary Heat Exchangers Secondary Heat exchangers shall be of a flow-through design having a patented interior laminate coating of polypropylene for greater corrosion resistance with fold-and-crimp design, which operates under negative pressure.Controls Controls shall include a microprocessor based integrated elec-tronic control board with at least 11 service troubleshooting codes displayed via diagnostic flashing LED light on the con-trol, has ability to store fault codes, when activated a self-test feature checks all major functions of the furnace within one minute, and a replaceable automotive-type circuit protection fuse. Multiple operational settings available including, sepa-rate blower speeds for low heat, high heat, low cooling, high cooling and continuous fan. Continuous fan speed may be ad-justed from the thermostat. Cooling airflow will be selectable between 350 or 400 CFM per ton of air conditioning. Features will also include temporary reduced airflow in the cooling mode for improved dehumidification when a Thermidistat® is selected as the thermostat.Operating Characteristics Heating Capacity shall be _________ Btuh input; ____________ Btuh output capacity.Fuel Gas Efficiency shall be 93% AFUE.Air delivery shall be __________ cfm minimum at 0.50 in. wg. external static pressure.Dimensions shall be: depth __________ in.; width __________ in.; height _________ in. (casing only). Height shall be __________ in. with A/C coil and ____________ in. overall with plenum.Electrical Requirements Electrical supply shall be 115 volts, 60 Hz, single-phase (nom-inal). Minimum wire size shall be _________ AWG; maximum fuse size or HACR-type, designated circuit breaker shall be _______ Amps. Special Features Refer to section of the product data sheet identifying accesso-ries and descriptions for specific features and available en-hancements.Guide SpecificationsPerformance 93Two-Stage Furnace 58MTB。

介绍宁夏当地带有意义的食物的英语作文

介绍宁夏当地带有意义的食物的英语作文全文共6篇示例，供读者参考篇1Ningxia's Delicious and Meaningful Local FoodsHave you ever tasted food that not only tastes amazing but also has a really cool story behind it? Well, in Ningxia, there are lots of local foods like that! I'm going to tell you about some of the most interesting and meaningful ones.First up is the Zhongning Bamboo Fungus. Thisfunny-looking mushroom grows on certain bamboo trees in Zhongning County. It kind of looks like a long stick with a big puffy cloud on top! The bamboo fungus has been eaten in Ningxia for over 300 years. Local people say it can help make your body stronger and even make you live longer. Pretty cool, right?The bamboo fungus grows best in areas with clean air and water, so finding it means the environment there must be really healthy. It's also not easy to farm, so the bamboo fungus you eat was most likely picked by hand from the forest. People in Ningxia really value this special mushroom.Next, we have the Tongxin Persimmon. Tongxin County is famous for growing the most delicious persimmons. These bright orange fruits are so sweet and yummy when they're ripe. But did you know there's an interesting tradition around them?For hundreds of years, people in Tongxin have made special persimmon cakes to give to friends and family. They thread the persimmons onto strings to dry them out, then flatten them into sweet cake shapes. Giving these cakes is a way to wish people happiness and long life. Isn't that a nice tradition?Another meaningful food from Ningxia is Wolfberry, also called Goji Berry. This little red berry has been used in Chinese medicine for ages because it's packed with healthy stuff like vitamins. Ningxia is one of the best places in the whole country to grow wolfberries.There are huge wolfberry farms and factories in Ningxia that produce tons of wolfberry products like juices, wines, and dried berries. Wolfberries from Ningxia get shipped all over China and even overseas because people everywhere want to eat this super healthy berry.Next up is one of my personal favorites - Huangzhong Dates! These sweet, chewy dates from Huangzhong County are famousall across Ningxia. They've been growing dates here for over 2,000 years because the hot, dry climate is perfect for it.What's really cool is that date palm trees can live for hundreds of years. Some of the date trees growing in Huangzhong today were planted centuries ago! The local people have taken great care of these ancient trees for generations, carefully tending them and harvesting the dates by hand each year.My last food is the Jingyuan Beef Noodles. This hearty beef noodle soup comes from Jingyuan County. The beef they use is from a special breed of cattle raised by local farmers. These cows graze on the open grasslands and drink water from mountain springs, making their meat super tender and tasty.The noodles are handmade from a recipe that's been passed down in families for a long time. When you slurp up a bowl of these beef noodles, you can taste the care and tradition that went into making them. No wonder Jingyuan Beef Noodles are so popular!Isn't it amazing how much history and culture is packed into the local foods of Ningxia? From mushrooms that show a healthy environment to ancient date palms tended for centuries, thesefoods really make you appreciate all the hard work and traditions of the people here. Plus, they're just downright delicious!The next time you travel to Ningxia or even just see one of these foods at the store, I hope you'll remember their special stories. Food isn't just about how it tastes - it can also connect us to the land, the people, and the rich heritage of a place like Ningxia. Now excuse me while I go grab a plate of those beef noodles!篇2My Favorite Foods from NingxiaHi there! My name is Xiao Ming and I'm from the amazing region of Ningxia in northwest China. Our province may not be as well-known as some others, but we have incredible food that I'm really excited to tell you about.You see, Ningxia is located along the ancient Silk Road trade routes that connected China to the rest of the world for centuries. Because of this, our cuisine has been influenced by many different cultures over a very long time. We take the absolute best flavors and ingredients from different places and blend them together in delicious and unique ways. Let me tell you about some of my favorite Ningxia foods!Ningxia Cured Beef (宁夏香吃)This is one of the most iconic and beloved dishes from our region. Cured or smoked meats were an important preservation technique used by traders traveling the Silk Road, and our version is just incredible.First, choice cuts of beef are rubbed with a special mixture of over 20 different spices like Sichuan pepper, fennel, cinnamon, star anise, and more. Then the meat is smoked over woods like peach or saxaul until it develops this rich reddish-brown color and insanely delicious flavor. When you eat Ningxia cured beef, the taste just explodes in your mouth with a mix of savory, sweet, sour, and spicy notes. It's chewy yet tender, and melts in your mouth. My grandma always makes extra because my cousins and I beg for more!Shuan Gu Li Bao (栈柜驴餅)These tasty little dumplings may not look like much, but they've been an energy-boosting staple food in Ningxia for centuries. The name literally means "pack on the donkey" because they were easily portable for traders to carry on long journeys along the Silk Road.Shuan gu li bao have a simple filling of lamb or beef mixed with green onions, ginger, and spices like cumin and fennel. But the real magic is in the dough wrapping, which uses a special fermented dough that gives the dumplings a wonderfully chewy texture and slightly sour flavor. They're boiled or steamed, then often pan-fried to get a crispy bottom. I always smother mine in my mom's homemade garlic sauce for dipping. Shuan gu li bao are so filling and energizing, yet surprisingly light at the same time. No wonder they kept traders fueled up!Yang Rou Pao Mo (羊肉馍馍)Let me tell you about one of the most iconic street foods in all of Ningxia - yang rou pao mo! Just thinking about it makes my mouth water. This is a humble yet insanely delicious lamb stew served over shredded flatbread.The meaty stew is made by simmering lamb on the bone for hours with a blend of spices like cumin, chili peppers, star anise, cinnamon, and more until it's fall-off-the-bone tender. The broth gets so rich and full of flavor. Meanwhile, soft flatbread rounds are shredded into nests to soak up all that deliciousness.When you order yang rou pao mo from a street vendor, they'll ladle the thick stew over the shredded bread and mix it all together right in front of you. The hot lamb blends with the soft,toasted bread to create pure magic in every bite. It's meaty, savory, spicy, a tiny bit sour from the fermented bread, and just all-around incredible. No visit to Ningxia is complete without devouring a big bowl of yang rou pao mo!Ningxia Dried Vinegar (臌乳/醮乳)I have to tell you about one of the most unique and ancient ingredients from Ningxia - our dried vinegar! Doesn't that just sound fascinating? It dates all the way back to the Han Dynasty over 2,000 years ago as a food preservation technique.Here's how it's made: first cow, goat, or sheep milk is gently heated until the liquid separates into curds and whey. Then the whey is collected and left to naturally ferment until it sours into a concentrated vinegar. Finally, the vinegar is dried into rock-hard bricks using traditional drying methods. Amazing, right?These dried vinegar "rocks" can be stored for a super long time and then grated or dissolved into liquids as needed to add a punchy sour taste. The flavor is more complex than regular vinegar and has hints of fruit and caramelized notes. My dad loves sprinkling it over potato dishes, dumplings, noodles, you name it! Dried vinegar really makes our Ningxia cuisine stand out in such a unique way.Nang Bread (烙饼)Last but definitely not least, I have to give a shoutout to one of my all-time favorite comfort foods - nang bread! If you come to Ningxia, you'll see families gathering around streetside tandoor ovens to enjoy these fresh, pillowy flatbreads hot off the fire.Nang dough is made with flour, water, yeast, and a bit of salt, then rolled out into circles before getting slapped against the sides of a clay oven. As they puff up and char lightly, the breads develop the most incredible crispy exterior while staying soft and chewy inside. They're usually brushed with lamb fat or sesame oil for extra flavor too. Mm mm!You can eat nang breads plain, which lets you appreciate their simple perfection. But they're also amazing stuffed or topped with other Ningxia specialties like cured beef, lamb stew, yogurt or cheese, and more. There's nothing better than ripping off a chunk of hot, fresh nang bread straight from the oven with your hands. It's one of my happiest food memories growing up!Well, there you have it - some of the most iconic and meaningful foods that make Ningxia's cuisine so incredibly special. From the melting flavors of our cured beef to the centuries-old portability of shuan gu li bao, each dish has such arich history tied to our province's role along the Silk Road. Ningxia food blends ingredients and techniques from all over in unique and mouthwatering ways.I feel so lucky to have been raised on these vibrant, diverse flavors that have been passed down through generations. Our local foods don't just nourish us physically - they connect us to our ancestors and the incredible legacy of cultural exchange that makes Ningxia so special. I really hope you get the chance to experience and taste these dishes for yourself someday!篇3The Tasty Treats of My Hometown NingxiaHi there! My name is Xiaoming and I'm from the beautiful region of Ningxia in northwest China. Today, I want to tell you all about some of the yummy local foods we have here that are really special. They're not just delicious, but they also have really cool histories and meanings behind them. Get ready to hear about some seriously tasty treats!First篇4The Flavors of Ningxia: A Taste of Local TreasuresHave you ever wondered what makes the food in Ningxia so special? Well, let me tell you all about the delicious and meaningful local dishes from this amazing region!First up, we have the famous Ningxia Lamb Soup. This hearty soup is made with tender lamb, fresh vegetables, and a secret blend of spices that will make your taste buds dance with joy! But did you know that this dish has a deeper meaning? In Ningxia, lamb is a symbol of prosperity and good luck. So, when you slurp up a bowl of this tasty soup, you're not just enjoying a delicious meal – you're also welcoming good fortune into your life!Next, let's talk about Ningxia Youxian Rice Noodles. These long, chewy noodles are handmade with love and served in a flavorful broth with vegetables and meat. But what makes them truly special is the tradition behind them. In the past, families in Ningxia would gather together to make these noodles, passing down the recipe from generation to generation. So, when you twirl these noodles around your chopsticks, you're not just eating a tasty dish – you're celebrating the bonds of family and tradition.Speaking of traditions, have you ever tried Ningxia Jiaozi? These plump dumplings are stuffed with a savory filling of meat, vegetables, and fragrant spices. But what makes them extraspecial is the way they're made. During the Lunar New Year, families in Ningxia come together to make hundreds of these dumplings, carefully folding and shaping each one by hand. It's a labor of love that represents the unity and togetherness of the family. So, when you bite into a juicy Ningxia Jiaozi, you're not just enjoying a delicious treat – you're tasting the warmth and love that went into making it.Now, let's move on to something a little sweeter: Ningxia Walnut Candies. These little balls of goodness are made by coating fresh walnuts in a sugary glaze, creating a delightful mix of crunchy and chewy textures. But did you know that walnuts have a special meaning in Ningxia? They're considered a symbol of fertility and prosperity, making these candies a popular gift for newlyweds or during the Spring Festival. So, when you pop one of these sweet treats into your mouth, you're not just satisfying your sweet tooth – you're savoring the hopes and well-wishes for a bountiful future.Last but not least, let's talk about Ningxia Wolfberry Wine. This ruby-red elixir is made by steeping plump wolfberries in a potent rice wine, creating a unique and refreshing beverage. But what makes this drink truly special is its connection to the local culture. In Ningxia, wolfberries are believed to have medicinalproperties and are used in traditional remedies. So, when you sip on a glass of this fragrant wine, you're not just enjoying a tasty drink – you're embracing the wisdom and heritage of Ningxia's traditional medicine.As you can see, the foods of Ningxia are more than just delicious dishes – they're a reflection of the rich culture, traditions, and beliefs that have been passed down for generations. So, the next time you have the chance to savor these local treasures, take a moment to appreciate the stories and meanings behind each bite. Who knows, you might just discover a new way to connect with the vibrant heritage of Ningxia!篇5Tasty Treats from NingxiaHi there! My name is Xiaoming and I'm from the amazing Ningxia Hui Autonomous Region in northwest China. Today I want to tell you all about some super yummy and really cool foods that come from where I live. Get ready to learn about dishes that are not only delicious, but also have special meanings and connections to my home's rich culture and history.Let's start with one of my personal favorites - Huangzhengai Nougat. This sticky, chewy candy is made from sugar, nuts, and milk solids. It might sound simple, but the process of making it is anything but! Candy masters have to stretch and fold the mixture over and over again until it becomes soft and velvety smooth. The end result is a melt-in-your-mouth treat that's been enjoyed in Ningxia for centuries.But Huangzhengai Nougat isn't just a regular old candy. Oh no, it has a really cool backstory! You see, back in the 1700s during the Qing Dynasty, there was a governor named Nayanceng who ruled over Ningxia. One day, he was visiting a village when he noticed some kids playing a game where they stretched gooey candy over and over. Nayanceng was amazed by how elastic and soft they could make it through all that pulling and folding. He decided this unique nougat should become a special food representing the area's cuisine. From then on, Huangzhengai Nougat's fame spread far and wide as a tasty symbol of Ningxia!Another famous Ningxia dish is Shuan Yang Rou, which means "tossed mutton" in English. This one is extra meaningful because it celebrates the area's Muslim culture. You see, many people in Ningxia follow Islam, and lamb is a very important foodin Islamic cuisine. Shuan Yang Rou features tender chunks of lamb or mutton that have been quickly stir-fried with chilies, cumin, salt, and other yummy spices. The meat gets a delicious crispy-on-the-outside, juicy-on-the-inside texture that'll make your taste buds do a happy dance!What I love most about Shuan Yang Rou, apart from how crazy good it tastes, is how it brings people together. Muslim families often make this dish to share on special occasions like holidays or celebrations. Can you imagine all the laughter and conversation flowing as everyone digs into the same flavorful platter? That's the real magic of Shuan Yang Rou - using food to create warm memories with loved ones.But we're not done yet! One more Ningxia delicacy I have to mention is the humble Xi Ren Zhang, or "date pie." This little pastry is cheap and easy to find, but don't let that fool you. Inside its crispy exterior is a gooey, sweet filling made fromlocally-grown dates mixed with nuts and fragrant rosewater. One bite gives you a flavor explosion of honey, floral notes, and satisfying chewiness.Xi Ren Zhang might be small, but it packs a big punch of history and culture. You see, dates have been growing in the deserts and oases of Ningxia for over 2,000 years! The area'ssultry summers and chilly winters create the perfect conditions for these wrinkly fruits to thrive. For generations, dates have nourished locals as a nutrient-rich food that could survive the harsh climate. By turning them into portable pies, people could take that life-sustaining energy on long journeys across the region's rugged terrain.Every time I munch into a Xi Ren Zhang's sticky stuffing, I imagine the resilient farmers, merchants, and nomads who kept Ningxia's culture alive by cultivating and trading dates over the centuries. This humble pie isn't just a snack - it's a symbol of my homeland's ability to adapt and thrive against all odds. How cool is that?Well, there you have it - three amazing Ningxia foods that feed your belly while giving you a taste of history, community, and local traditions. From the labor of love that is Huangzhengai Nougat to the socially-connecting powers of Shuan Yang Rou to the journey through time inside each Date Pie, every bite lets you experience the incredible stories woven into my home's cuisine.The next time you're looking for something to nosh on, don't just think about how it'll taste. Ask yourself - what cultures, memories, and legends are baked, folded, or stir-fried into that meal? You might discover, like I did, that food has a way ofnourishing both your body and mind through its rich meanings and roots. Isn't that just the most deliciously wonderful thing?篇6Delicious Foods from NingxiaHi everyone! My name is Xiao Ming and I'm from Ningxia, a province in northwest China. Today I want to tell you all about some of the yummy foods we eat where I'm from. Ningxia has a long history and diverse cultures, so our foods are really unique and special. Get ready to learn about some amazing dishes!One of my absolute favorite Ningxia foods is nang. It's a kind of flatbread that's crispy on the outside but soft and chewy on the inside. Nang comes in different shapes like circles, rectangles, or even animal designs. The dough gets rolled out super thin before being fried in oil. You can have nang plain, or stuffed with ingredients like lamb, vegetables, or sweetened condensed milk. Yum!Whenever my grandma makes nang, the whole house smells incredible. She lets me help roll out the dough and shape the little breads. Eating fresh nang hot out of the pan is the best, but you can also pack it for a snack later. Nang is convenient food you can take anywhere.Another beloved Ningxia dish is jiuba, which means "fritters." These crispy fried snacks can be made with all sorts of ingredients like potatoes, wheat, corn, or even beef. But the most popular kind is lamb jiuba. First, ground lamb gets mixed with spices, green onions, garlic, and other yummy seasonings to make a flavorful dough. Then little pieces are pinched off, rolled into balls, and deep fried until crispy on the outside and tender inside.Lamb jiuba are irresistibly crunchy and savory. You can't eat just one! My grandpa always makes a huge batch because they disappear so fast. Jiuba are perfect for sharing with family and friends. People often serve them at parties or get-togethers in Ningxia. Popping a few crispy lamb bites in your mouth is pure joy.One more amazing Ningxia food is yangrou nainiu, which means "lamb and dairy cow" soup. It's a rich, hearty stew made by simmering lamb and beef together with potatoes, carrots, daikon radish, and other veggies. The broth gets its amazing flavor from hours of gentle simmering. Yangrou nainiu is warm, comforting food that brings people together.On chilly Ningxia nights, my mom makes a huge pot of yangrou nainiu to share with our whole family. We sit around thetable, each with our own bowl, taking turns scooping up bites of tender meat and veggies. The savory broth warms you right up! Everyone slurps it down happily. Yangrou nainiu reminds me of cozy family time. I cherish those delicious memories.Foods from Ningxia are so meaningful because they connect us to our culture and traditions. When I eat nang, jiuba, or yangrou nainiu, I feel proud of where I come from. These humble but delicious dishes have been bringing people together for centuries.Eating is much more than just nourishment in Ningxia. It's about sharing, bonding, and celebrating our way of life. Our unique local foods keep our heritage alive by passing down recipes from grandparent to parent to child. I feel lucky to grow up savoring such amazing flavors.I hope you enjoyed learning about some classic Ningxia cuisine! Nang, jiuba, and yangrou nainiu are just a few examples of our province's delicious and meaningful foods. Maybe someday you'll visit and get to taste them for yourself. Let me know if you have any other questions - I'm always happy to share more about the awesome dishes from my homeland!。

制作奶酪的英文作文

制作奶酪的英文作文English Answer:Cheesemaking is a culinary art that involves the transformation of milk into a solid, concentrated food product. It is an ancient practice that has been passed down through generations, and different regions of the world have developed their own unique methods and flavors of cheese.The basic process of cheesemaking involves the coagulation of milk proteins, the separation of the curds from the whey, and the subsequent aging and ripening of the cheese. Coagulation can be achieved through the use of rennet, an enzyme that breaks down the milk proteins, or through the addition of acids, such as vinegar or lemon juice.Once the milk has coagulated, the curds are cut into small pieces and heated gently to encourage furtherseparation of the curds and whey. The curds are then drained and pressed into molds to form the final shape of the cheese.The aging and ripening process is essential for the development of the cheese's flavor and texture. Cheeses can be aged for anywhere from a few weeks to several years, and the aging process can take place in a variety of environments, including caves, cellars, and warehouses. During this time, the cheese undergoes a series of biochemical changes that result in the development of its characteristic flavors and aromas.There are hundreds of different types of cheese, each with its own unique flavor, texture, and appearance. Some of the most popular types of cheese include cheddar, mozzarella, Parmesan, and brie. Cheese can be used in a variety of dishes, from sandwiches and salads to pizzas and pasta dishes. It can also be enjoyed on its own as a snack or appetizer.Cheesemaking is a complex and fascinating process thatrequires careful attention to detail. With a little practice, however, it is possible to make delicious and flavorful cheeses at home.中文回答：奶酪制作是一门烹饪技艺，它涉及将牛奶转化为固体、浓缩的食品。

制作奶酪过程英文作文

制作奶酪过程英文作文First, the milk is heated to a specific temperature and then a starter culture is added to begin the fermentation process. This helps to acidify the milk and create the characteristic tangy flavor of cheese.After the milk has been acidified, rennet is added to coagulate the milk and form curds. The curds are then cut into small pieces to release the whey, which is the liquid part of the milk.The curds are then cooked and stirred to expel more whey and firm up the texture of the cheese. This process helps to develop the desired texture and flavor of the cheese.Once the curds have reached the desired texture, they are drained and pressed into molds to further expel excess whey and shape the cheese. The cheese is then left to age for a specific period of time to develop its flavor andtexture.During the aging process, the cheese is often turnedand rubbed with salt to help develop its rind and flavor. This step is crucial in creating the unique characteristics of each type of cheese.Finally, the cheese is ready to be enjoyed! Whetherit's a creamy brie, a sharp cheddar, or a tangy blue cheese, the process of making cheese is a labor of love thatresults in a delicious and versatile food product.。

磨豆腐真的很有趣开头英语作文

磨豆腐真的很有趣开头英语作文Grinding the Millstones: A Culinary Adventure in Tofu Making.In the tapestry of culinary arts, tofu stands as a culinary marvel, a versatile protein that graces tables worldwide. Its origins are steeped in ancient Chinese history, dating back to the Han dynasty. Legend has it that a culinary virtuoso stumbled upon the wonderous creation by accident, accidentally coagulating soybean milk with nigari, a natural coagulant derived from seawater.The process of transforming soybeans into the soft, velvety texture of tofu is an art form in itself. Itrequires patience, precision, and a touch of culinary alchemy. Like a sculptor chiseling away at a block of marble, tofu makers delicately mold and shape the soybeans, coaxing them into a form that delights the senses.The journey begins with the humble soybean, a legumebrimming with nutritional riches. These tiny orbs are meticulously washed and soaked overnight, imbibing water until they swell and soften. The next morning, they are ground into a smooth slurry using a traditional stone mill. The grinding process is a gentle dance, the millstones rotating at a leisurely pace to preserve the soybeans' delicate integrity.The resulting soybean milk is a milky liquid, its creamy color hinting at the culinary magic that lies ahead. It is carefully heated to a precise temperature, stirring constantly to prevent scorching. As the milk simmers, a coagulant is gradually added, causing the proteins to denature and form curds. The coagulant of choice varies by region and tradition, with nigari, calcium sulfate, or glucono-delta-lactone being common options.The curds and whey gently separate, the curds forming a delicate veil that floats upon the surface. With practiced hands, the tofu maker carefully scoops up the curds using a cheesecloth-lined colander. The whey, a nutrient-rich liquid, is drained away, leaving behind the nascent tofu.The freshly formed tofu is then pressed to remove any remaining whey and achieve the desired firmness. This can be done using a variety of methods, from simple weights to sophisticated hydraulic presses. The pressing time and weight determine the texture of the tofu, from the soft and silken to the firmer and denser varieties.The final step in the tofu-making process is cooling. The pressed tofu is submerged in cold water or placed in a refrigerator to cool and set. This step helps to stabilize the texture and prevent the tofu from drying out.And thus, the transformation is complete. The humble soybean has been reborn as tofu, a culinary chameleon that can be enjoyed in a myriad of ways. It can be steamed, fried, grilled, or simmered, absorbing flavors like a culinary sponge. Tofu is a staple in Asian cuisine, but its versatility has earned it a place on dinner tables across the globe.Making tofu from scratch may seem like a daunting task,but it is a rewarding culinary adventure that yields a profound appreciation for the art of food. It is a process that connects us to our culinary heritage and invites us to savor the simple joys of homemade goodness.As you embark on your own tofu-making journey, remember the words of the ancient Chinese philosopher Lao Tzu: "The journey of a thousand miles begins with a single step." Embrace the process, enjoy the unfolding culinary alchemy, and revel in the satisfaction of creating a culinary masterpiece with your own hands.。

大豆乳清蛋白的热促凝聚及其对分离蛋白功能性的影响

大豆乳清蛋白的热促凝聚及其对分离蛋白功能性的影响叶凌凤,徐婧婷,郭顺堂(中国农业大学食品科学与营养工程学院,北京100083 )摘要:分别在pH8. 0和pH4. 5对“碱提酸沉”法制备大豆分离蛋白过程中所得提取液进行热处理,研究了大豆乳清蛋白的热促凝聚效果及其对所制备分离蛋白功能性的影响。

结果表明: 加热处理可降低大豆乳清中乳清蛋白的含量,在pH8. 0和pH4. 5时提取液经70℃加热10 m in分别使25. 7%和40 %乳清蛋白转移到分离蛋白产品中。

以普通分离蛋白为对照,对3种分离蛋白产品进行功能性分析,发现3种产品均在pH4. 5～4. 8的范围内溶解度最小, 70℃加热10 m in所制备分离蛋白的持水性明显高于普通分离蛋白,但其持油性、起泡性、泡沫稳定性和乳化性均低于普通分中图分类号: TS214. 2文献标识码: A文章编号: 1000 29841 ( 2010 )02 20288 204Therm a l A g grega t i on of Soybean W hey Pro t e in an d Its Effec t on the Fun c t i ona l Proper t i e s of Soy Pro t e in sYE L i ng2feng, XU J i ng2ti ng, G UO Shun2tang( Co llege of Food Sc i ence and N u tritiona l Enginee ring, Ch ina A gricu ltu r al U n ive rsity, B e ijing 100083 , Ch ina)A b stra c t: The rec lam a t ion of s oybean whey p r o te in (W S P) can b ring econom ic benefits an d reduce environm en ta l po l l u t i o ndu rin g s oybean p r o te in p r oduc tion. Extrac t s a t pH 8. 0 and pH4. 5 we re hea ted to ob se rve the the r m a l ag grega tion of W S P and its effec t on the func t i o na l p r op e r tie s of soy p r o t e i n s. R e s u l ts showed tha t hea t trea t m e n t reduced the con t en t of W S P in s oy2 bean whey, extrac t s a t pH 8. 0 and pH4. 5 we r e hea t ed by 70 ℃w ith 10 m inu t e d i ve r ted 25. 7% and 40% W S P in t o s oybean p ro t e in s Is o la ted ( S P I) , re sp ec t ive ly. Func tiona l p r op e rtie s ana lysis of th ree k ind s S P I ind ica ted tha t they a ll had the m i n i2 m u m so lub ility du ring pH4. 5 24. 8. S P I p rep a ring by hea ted by 70 ℃w ith 10 m inu te had h ig he r wa te r ho ld ing p r o p e r ty than common S P I, bu t had lowe r o il ho ld ing p r op e rty, foa m ing p r op e rty and foam ing stab ility than common S P I, and had n o sig2 n i fican t d i ffe r ence fo r em u l sify stab i lity.Key word s: S oybean whey p r o t e i n; A lka l i extrac t ion and ac i d p rec i p ita t ion; The r m a l ag greg a t ion; Func t i o na l p rop e r tie s“碱提酸沉”法是制备大豆分离蛋白的常规方法,将豆粕用偏碱性的水为溶剂进行抽提, 绝大部分大豆蛋白质可被提取出来。

Presenting

18
4
1/2 skim
milk
7
0 0 10
0
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1
carbohydrate
(1) Flavors: Banana, Blueberry, Boysenberry, Cherry, French Vanilla, Harvest Peach, Key Lime Pie, Mandarin Orange, Mixed Berry, Orange Creme, Pineapple, Raspberry, Raspberry Lemonade, Strawberry, Strawberry Banana, Strawberry Cheesecake, Strawberry Kiwi, Strawberry Mango, Tropical Peach, White Chocolate Raspberry, Tropical, Blackberry (2) Flavors: Harvest Peach, Mixed Berry, Raspberry, Strawberry, Strawberry Banana (3) Flavors: Banana, Blueberry, Cherry Vanilla, Lemon, Peaches 'n Cream, Raspberry, Strawberry, Strawberry Banana, Key Lime Pie, Raspberry Cheesecake, Orange Creme, Tropical Fruit (4) Flavors: Strawberry, Raspberry, Peaches 'n Cream, Strawberry Banana, Strawberry Vanilla (5) Flavors: Apricot Mango, Berries 'n Cream, Blueberry, Cherry, Key Lime Pie, Peach, Raspberry, Raspberry Peach Melba, Strawberry, Strawberry Banana, Strawberry Orange Sunrise, White Chocolate Strawberry (6) Flavors: Banana Cream, Boston Cream Pie, Key Lime Pie, Lemon Cream Pie (7) Flavors: Harvest Peach, Key Lime, Lemon Burst, Mixed Berry, Peaches & Cream, Raspberry, Strawberry (8) Flavors: Cotton Candy, Raspberry Rainbow, Strawberry Banana Bash, Strawberry Kiwi, Strawberry Punch, Triple Cherry, Watermelon Burst, Wild Berry Blue, Bubble Gum, Rainbow Sherbet (9) Flavors: Berry Blue, Cherry, Cotton Candy, Punch, Raspberry, Strawberry, Strawberry Banana, Strawberry Kiwi, Watermelon, Melon Berry

做水豆腐作文英语

做水豆腐作文英语Title: Making Silken Tofu: A Culinary Journey。

Silken tofu, also known as water tofu, is a delicate and smooth variety of tofu that is cherished in Asian cuisine for its silky texture and versatility. Crafting silken tofu is not only a culinary art but also a process that intertwines tradition with modern techniques. In this essay, we will delve into the intricate steps involved in making silken tofu and explore its significance in the culinary world.The journey of making silken tofu begins with the humble soybean. These small legumes are soaked, ground, and then boiled to extract their essence. The resulting soy milk forms the foundation of silken tofu. The process of transforming soy milk into silken tofu is where the magic truly happens.Once the soy milk is extracted, it is gently heated andcombined with a coagulant. Traditionally, nigari, a natural mineral extract, is used as the coagulant. However, other coagulants such as gypsum or lemon juice can also be employed. The choice of coagulant influences the texture and flavor of the final product.As the coagulant is introduced to the soy milk, a chemical reaction occurs, causing the proteins to coalesce and form curds. Unlike firm tofu, which undergoes vigorous pressing to expel excess water, silken tofu is delicately handled to preserve its soft and custard-like consistency. The curds are carefully ladled into molds lined with cheesecloth, allowing the excess whey to drain away naturally.Next comes the crucial step of setting the tofu. Traditionally, the molds are placed in a wooden frame called a tofu box and left to rest undisturbed for several hours. During this time, the tofu gradually firms up while retaining its characteristic smoothness. In modern production, mechanical presses or automated systems may be used to streamline the process, but the essence of allowingthe tofu to set remains unchanged.Once the tofu has reached the desired consistency, it is carefully unmolded and chilled to enhance its texture and flavor. Silken tofu is prized for its versatility, as it can be incorporated into both savory and sweet dishes. Its subtle flavor allows it to harmonize with a wide range of ingredients, making it a favorite among chefs and home cooks alike.In addition to its culinary appeal, silken tofu boasts numerous health benefits. It is a rich source of protein, making it an excellent choice for vegetarians and vegans seeking to meet their dietary requirements. Silken tofu is also low in calories and contains no cholesterol, making it a heart-healthy alternative to animal-derived proteins.Furthermore, silken tofu is packed with essential nutrients such as calcium, iron, and magnesium, which are vital for maintaining bone health and overall well-being. Its high water content contributes to hydration and aids in digestion, making it a nourishing addition to any meal.In conclusion, the process of making silken tofu is a labor of love that combines tradition, science, andculinary expertise. From humble soybeans to delicate curds, each step in the journey plays a crucial role in creating this beloved ingredient. Whether enjoyed steamed, fried, or blended into a smoothie, silken tofu continues to captivate palates around the world with its exquisite taste and nutritional benefits. So, the next time you savor a dish made with silken tofu, take a moment to appreciate the craftsmanship and tradition behind this culinary treasure.。

2024年09版小学六年级第三次英语第3单元真题(含答案)

2024年09版小学六年级英语第3单元真题(含答案)考试时间：90分钟（总分:110）A卷考试人：_________题号一二三四五总分得分一、综合题(共计100题)1、填空题：In gym class, we learn to play different sports and stay ________ (健康).2、听力题：Shale is a type of sedimentary rock that is formed from ______ clay particles.3、What is 10 divided by 2?A. 2B. 5C. 10D. 20答案: B4、听力题：The ______ helps us learn about art.5、听力题：A ______ is an area of land that drains into a river.6、听力题：My favorite color is _____. (purple)7、climate resilience) strengthens communities against climate impacts. 填空题：The ____8、What is the freezing point of water?A. 0 degrees CelsiusB. 10 degrees CelsiusC. 100 degrees CelsiusD. -10 degrees Celsius答案:A9、填空题：I want to _______ a new video game.10、What is the primary ingredient in pasta?A. RiceB. WheatC. CornD. Oats答案:B. Wheat11、听力题：A polymer is a large molecule made up of many ______ units.12、填空题：He is a scientist, ______ (他是一名科学家), studying climate change.13、What do you call the time when the sun is highest in the sky?A. MorningB. NoonC. EveningD. Night14、What is the capital of Malawi?A. LilongweB. BlantyreC. MzuzuD. Zomba答案:A15、Which fruit is red and often associated with teachers?A. BananaB. AppleC. OrangeD. Grape16、听力题：They are _____ (drawing) with chalk.17、填空题：A _____ (金鱼) can live in a fishbowl.18、What do you call the front of a boat?A. SternB. BowC. PortD. Starboard答案:B19、听力题：The chemical structure of water is described as _____ (HO).20、选择题：What is the main ingredient in butter?A. MilkB. EggC. SugarD. Flour21、听力题：A solute can be a solid, liquid, or ______.22、What is the capital city of Japan?A. BeijingB. SeoulC. TokyoD. Bangkok23、填空题：The frog jumps from rock to ______.24、填空题：A cat has excellent ______ (视力) at night.25、填空题：A starfish can regrow lost ________________ (臂).26、填空题：I enjoy going ________ (远足) in nature.27、填空题：The flower needs sunlight and ______.28、听力题：The chemical formula for ammonium chloride is ______.29、填空题：The ________ (森林保护) is vital for the planet.30、听力题：His favorite game is ________.31、What is the name of the largest land animal?A. RhinocerosB. HippopotamusC. ElephantD. Giraffe答案：C32、听力题：She likes to eat _____ (苹果).33、选择题：What do we call the time when everything is quiet?A. NoiseB. SilenceC. SoundD. Music34、What is the chemical symbol for water?A. H2OB. CO2C. O2D. NaCl35、How many vowels are in the English language?A. ThreeB. FourC. FiveD. Six36、填空题：The rain is ________ (下得很大).37、填空题：The _______ (Stone Age) represents the earliest known period of human culture.38、听力题：A _______ can measure the amount of current flowing through a wire.39、What do you call a large animal that lives in the ocean and has fins?A. SharkB. DolphinC. WhaleD. All of the above答案:DThe ______ is very wise and gives good advice.41、填空题：I walk to school every ________ (天).42、填空题：My pet dog is very ______.43、填空题：My __________ (玩具名) is my best __________ (名词).44、填空题：The kitten loves to play with ______.45、填空题：The seahorse is the only animal where the male carries the ________________ (幼崽).46、听力题：I love to _____ in the garden. (play)47、听力题：The _____ (city/country) is big.48、填空题：The ancient Romans built ________ to improve transportation.49、填空题：The sky is _______ (非常晴朗).50、How do you say "cat" in French?A. ChatB. KatzeC. GatoD. Puss51、 (World War) II lasted from 1939 to 1945. 填空题：The ____52、听力题：The Pacific Ring of Fire is known for its high number of ______ and earthquakes.53、听力题：A _______ is formed when two or more elements combine chemically.The chemical formula for calcium carbonate is ______.55、Who is the main character in "Harry Potter"?A. HermioneB. RonC. HarryD. Draco答案: C56、填空题：My _____ (小鼠) runs on its wheel.57、What is the term for a baby rabbit?A. KitB. PupC. LeveretD. Bunny答案:A58、填空题：The __________ (历史的交响) celebrates diversity.59、What is the capital city of France?A. ParisB. LondonC. BerlinD. Rome答案:A60、填空题:I eat ________ for breakfast every morning.61、听力题：The bear explores the forest looking for ____.62、听力题：The chemical symbol for rubidium is _______.63、填空题：I want to _______ (去旅行)到不同的地方。

水解乳清蛋白工艺流程的研究

水解乳清蛋白工艺流程的研究张俊英;孟艳琴;杨建华;张做林【摘要】本文以降低乳清蛋白(WPC80)中的主要过敏原为依据,研究了乳清蛋白的水解工艺流程,并详细陈述了加热、pH值对水解产物过敏原含量的影响,以及沸水浴时间对灭酶活的影响等加工处理方法对牛乳过敏原的影响,对开发无过敏或低过敏的乳制品具有一定指导作用.【期刊名称】《乳业科学与技术》【年(卷),期】2011(034)002【总页数】3页(P55-57)【关键词】乳清蛋白;过敏原;蛋白酶A;水解工艺【作者】张俊英;孟艳琴;杨建华;张做林【作者单位】内蒙古鄂尔多斯市农牧学校,内蒙古鄂尔多斯,014300;内蒙古鄂尔多斯市农牧学校,内蒙古鄂尔多斯,014300;内蒙古伊利集团液态奶事业部锡林浩特伊利乳品有限责任公司,内蒙古锡林郭勒,026000;内蒙古伊利集团液态奶事业部锡林浩特伊利乳品有限责任公司,内蒙古锡林郭勒,026000【正文语种】中文【中图分类】TS252.59牛乳是优质的营养食品，尤其乳蛋白质是牛乳中最有价值的成分。

但是牛乳和人乳的蛋白质成分存在较大的差异，牛乳中酪蛋白与乳清蛋白的含量比为8:2，而人乳中酪蛋白和乳清蛋白的含量比为 4:6，并且牛乳中αs-酪蛋白和β-乳球蛋白（β-LG）是人乳中没有的，也是牛乳中主要的过敏原[2-4]，因此一些婴幼儿饮用牛乳之后容易产生过敏反应[1]。

据随机选择新生儿前瞻性纵向研究显示，5 %～15 %的婴幼儿具有牛乳过敏和牛乳不耐受（CMA/CMI）症状[5]。

发达国家十分重视牛乳蛋白过敏的研究和防治，而国内对食物过敏问题重视不够，相关资料报道极少，对牛乳中过敏原的研究确定多依赖西方国家的研究资料，缺乏对我国儿童牛乳蛋白过敏原的相关研究。

目前，人们对食品安全的关注日益增加，牛乳蛋白过敏也越来越受到重视。

因此，本文将对我国牛乳蛋白过敏患儿的主要过敏原——乳清蛋白的水解工艺（包括加热、pH值、沸水浴时间对灭酶活的影响等）进行研究，对生产防治牛乳蛋白过敏的低致敏婴儿配方奶粉具有重要的意义。

制作奶酪英文作文

制作奶酪英文作文Title: The Art of Cheese Making。

Cheese making is a time-honored craft that has been practiced for centuries, producing a wide variety of flavors, textures, and aromas that delight the senses. From creamy bries to sharp cheddars, each type of cheese carries its own unique characteristics, making it a fascinating subject to explore.To embark on the journey of cheese making, one mustfirst understand the fundamental process involved. It all begins with milk, the primary ingredient. Whether it's cow, goat, or sheep milk, the quality and freshness are paramount to the final product. The milk is heated and then mixed with a starter culture, which introduces beneficial bacteria to kickstart the fermentation process. Thisculture plays a crucial role in developing the flavor and acidity of the cheese.Next comes the addition of rennet, an enzyme that helps coagulate the milk, forming curds and whey. The curds are then cut and stirred, releasing more whey and compacting the curds into a solid mass. The size of the curds and the duration of stirring greatly influence the final texture of the cheese, whether it be soft and spreadable or firm and crumbly.Once the curds have reached the desired consistency, they are transferred into molds to shape the cheese. This step allows for further manipulation of the texture and appearance, whether it's a classic wheel or a unique artisanal shape. The cheese is then pressed to expel any remaining whey and to encourage proper aging and flavor development.After pressing, the cheese enters the aging process, where it undergoes biochemical changes that enhance its flavor profile. Factors such as temperature, humidity, and time play crucial roles in determining the final taste and texture of the cheese. Some cheeses are aged for just a few weeks, while others may mature for months or even years,developing complex flavors and aromas along the way.Throughout the aging process, cheesemakers carefully monitor and tend to their cheeses, turning them, brushing off any mold, and ensuring optimal conditions for aging. This attention to detail is what sets artisanal cheeses apart, as each batch is a labor of love, imbued with the skill and expertise of the cheesemaker.Finally, after weeks or months of aging, the cheese is ready to be enjoyed. Whether it's served on a cheese board, melted into a dish, or simply savored on its own, the culmination of flavors and textures is a testament to the artistry of cheese making.In conclusion, cheese making is a nuanced and intricate process that yields a diverse array of culinary delights. From the humble farmhouse cheddar to the luxurious camembert, each cheese tells a story of tradition, craftsmanship, and innovation. So the next time you bite into a piece of cheese, take a moment to appreciate theskill and dedication that went into creating it.。

高考英语阅读理解科普文(难度较高)之欧阳学创编

2014年高考英语二轮复习阅读理解拉分题（较难题目）特训：节能环保类1The Goldman Environmental Foundation recently recognized a group of individuals (个体) for their efforts to protect the environment. Each year, the American-based group honors environmental activists from six different areas.The first three winners of the 2012 Goldman Prize are from Kenya, the Philippines and China.The Goldman Environmental Foundation says Ikal Angelei is a hero to those who live around Lake Turkana. The Kenyan woman received the award because of her efforts to stop a dam project on a river in Ethiopia. Critics say the dam will harm the lake and restrict (限制) the flow of water for people who live nearby.The Philippine island of Mindoro is home to those who depend on the area’s natural resources for food and jobs. Edwin Gariguez became concerned when a European company announced plans to mine for nickel (镍) on the island. The Roman Catholic minister said waste materials from the mining project would pollute the water and destroy the forests. So he started a campaign to stop the project.In China, Ma June is working with businesses to clean up their pollution. He formed a group that collects information about pollution, and publishes it on the Internet.The Goldman Prize was also awarded to activists from Argentina, Russia and the United States.Sofia Gatica of Argentina is from a town where farmers commonly use pesticide (杀虫剂) products to protect soybean crops from insects. The town also has a high rate of cancer. Sofia Gatica believed that pesticide use was responsible for the death of her baby. She worked with other mothers to get government officials to ban the use of chemicals near populated areas.Evgenia Chirikova objects to the plans to build a road througha protected forest just outside Moscow. She has demanded that Russian officials redirect the road away from the forest. She and her followers have been arrested for their activities. However, their campaign has gained widespread public support.The sixth winner is American Caroline Cannon—a community leader in Point Hope, Alaska. Miz Cannon is fighting to keep Arctic waters safe from oil and gas exp loration.60. We can know from the passage that ______.A. the dam project has been preventedB. the first three activists are all from AsiaC. a European company is going to dig for nickelD. Ma June is trying to stop oil and gas exploration61. From the 7th paragraph, we can know that ______.A. pesticide use accounts for a high-rate of cancerB. Sofia managed to ban the use of chemicalsC. the farmers mainly live on unpolluted productsD. the death of the baby was due to delayed treatment62. What do we know about Evgenia Chirikova？A. She plans to build a road to protect the forest.B. She is in charge of a project far away from the road.C. She persuaded the government to set her followers free.D. Her environmental action has been widely acknowledged.63. What would be the best title for the passage?A. Six Advanced Individuals for Hard WorkB. Efforts to Create a Clean and Beautiful WorldC. Six Environmental Activists Win Goldman PrizeD. The Goldman Environmental Foundation Prize2SCS Global Services （SCS） has evaluated a new methodology for measuring the carbon sequestration（封存）ability of soil under the Verified（验证） Carbon Standard （VCS）, a leading greenhouse gas （GHG） accountingsystem. The methodology, developed by The Earth Partners, will allow land managers who sequester GHGs in grasslands and farmlands to produce carbon credits for sale in the voluntary market.Managers of grasslands and farmlands can increase carbon sequestration in soil by practices such as changing grazing （放牧） practices and operating treatments designed to improve the variety and productivity of plant groups. The Earth Partners is presently piloting this methodology with farmers across seven million acres of the Palouse River and Columbia Plateau regions in the Pacific Northwest.“The VCS p rogram has achieved an important milestone in now combining grassland and rangeland carbon offset（抵消，补偿） projects," said Dr. Robert J. Hrubes, Executive Vice President of SCS."SCS looks forward to approving and verifying agricultural carbon offset projects that use this very powerful new methodology."The VM0021 Soil Carbon Quantification Methodology is based on decades of soil carbon research and testing conducted by top soil scientists. The methodology was developed by TheEarth Partners and verified by Environmental Services, Inc. as well as SCS Global Services. It is the first soil carbon methodology to be approved for use under the VCS."This widely tested methodology is the first to specially deal with soils in a market," said Steven I. Apfelbaum, Chairman of Applied Ecological Services, Inc. and Director of Science with The Earth Partners. According to Apfelbaum, soils represent the second largest living sink of carbon on the planet.68. The new methodology is assessed according to.A. The Earth PartnersB. the Verified Carbon StandardC. Environmental Services, Inc.D. Applied Ecological Services, Inc.69. Carbon sequestration in soil can be strengthened by.A. selling carbon credits in the voluntary marketB. changing grazing practices and operating treatmentsC. reducing the variety and productivity of plant groupsD. decreasing farmlands in the Pacific Northwest70. Which of the following is true according to the passage?A. The VCS program proves to be successful in carbon offset projects.B. Many soil Carbon Methodologies have already been approved for use.C. The new methodology has been tested in many fields including soil.D. Soils seem to be the largest living sink of carbon on the planet.71. What is the attitude of SCS towards the new methodology?A. Opposed.B. Cautious.C. Doubtful.D. Approving.3Rainforest is home to around two-thirds of all plant and animal species found on land—in addition to millions of people who depend on them for survival—our remaining ancient forests are some of the most diverse ecosystems known to science. They are also vitally important to the health of our planet, especially when it comes to regulating the climate. But ancientforests around the world are under attack.Protecting rainforests is on the global agenda (议事日程) in a big way. Governments now recognize the importance of protecting tropical forests in order to avoid dangerous climate change, and there is now much debate. As governments try to thrash out the details of a new international agreement, expected to be signed at the end of 2009, they are discussing how best to include measures to save rainforests, and therefore address one of the major causes of climate change. Worldwide, forest destruction causes more greenhouse gas emissions (排放) each year than do all the trains, planes and cars on the planet. So if we are to deal with global warming, there is an urgent need to find ways to reduce the 20% of global greenhouse gas emissions caused by forest destruction each year, and to keep the remaining forests standing.We need to protect the planet’s remaining forests not only to stop climate change from getting worse, but to ensure that we can stand the impacts of global warming. Healthy forests absorb and store quantities of carbon, helping to regulate temperature and generate rain. When they are destroyed, this carbon is released into the atmosphere. Thus keeping forestsstanding is both a critical part of regulating climate change and of adapting to a warmer world.To date, most of the talk has focused on how to pay for reducing deforestation (滥伐森林), rather than on how to actually go about doing it. We believe governments need to support local people to protect their environment, as we have been showing for 20 years can be a very effective way of saving rainforests.1. The best title for the passage is.A. Rainforest and Climate ChangeB. Strategies on Protecting RainforestC. Serious Deforestation to RainforestD. Present Situation of Rainforest2. From the first paragraph we can infer that.A. we have little rainforest left until nowB. the ancient forests are being destroyedC. rainforest control the planet in many waysD. Rainforest is home to all plants and animals on earth3. The underlined part “thrash out” in the second paragraph means.A. try to understandB. come up withC. hide awayD. have a thorough discussion4. Greenhouse gas emissions caused by forest destruction.A. are the same amount by transport on earthB. take 20% of global greenhouse gas emissionsC. can be avoided by setting measures onlyD. have nothing to do with climate change5. From the text we can learn that healthy forest.A. can keep us healthy and happyB. can increase the effect from global warmingC. can be helpful in adjusting the temperatureD. can give out large amounts of carbon4Rivers may be a significant source of the greenhouse gas nitrous oxide (一氧化二氮), scientists now find.Their calculation suggests that across the globe the waterways contribute three times the amount of nitrous oxide to the atmosphere as had been estimated by the International Panel on Climate Change (IPCC), the United Nations scientific body charged with reviewing climate change research. They found that the amount of nitrous oxide produced in streams is related to human activities that release nitrogen (氮) into the environment, such as fertilizer use and sewage discharges. “Human activit ies, including fossil fuel combustion and intensive agriculture, have increased the availability of nitrogen in the environment,” said Jake Beaulieu of the University of Notre Dame and the U.S. Environmental Protection Agency in Cincinnati, Ohio, and lead author of the paper published this week in the journal Proceedings of the National Academy of Sciences.“Much of this nitrogen is transported into river and stream networks,” Beaulieu said. There, microbes (微生物) convert the nitrogen into nitrous oxide (also called laughing gas) andan inert gas called dinitrogen (二氮).The finding is important, the researchers say, because nitrous oxide is a powerful greenhouse gas that contributes to climate change and destruction of the stratosphere’s ozone layer, which protects us from the sun’s harmful ultraviolet (紫外线) radiation. Compared with carbon dioxide, nitrous oxide is 300-fold more powerful in terms of its warming potential, though carbon dioxide is a far more common greenhouse gas. Scientists estimate nitrous oxide accounts for about 6 percent of human-induced climate change.Beaulieu and colleagues measured nitrous oxide production rates in 72 streams. When summed across the globe, the results showed rivers and streams are the source of at least 10 percent of human-caused nitrous oxide emissions to the atmosphere. “Changes in agricultural and land-use practices that result in less nitrogen being delivered to streams would reduce nitrous oxide emissions from river networks,” Beaulieu said.1. From the second paragraph we can learn.A. actually rivers give off much more nitrous oxide thanexpectedB. scientists’ calculation is totally wrongC. human activities release nitrous oxide in to the riversD. there is no nitrogen in fertilizer2. Which of the following is NOT the source of nitrogen?A. Fertilizer use.B. Sewage discharges.C. Fossil fuel combustion.D. Climate change.3. Nitrous oxide is a powerful greenhouse gas because.A. it can protect us from the sun’s harmful ultraviolet radiationB. it is to blame for most of human-induced climate changeC. it is a far more common greenhouse gasD. it has much more warming potential than carbon dioxide4. What does the passage mainly tells us?A. Rivers may be a source of the greenhouse gas nitrous oxide.B. It’s human activities that release nitrogen into the environment.C. How to reduce nitrous oxide emissions from river networksD What to do with the climate change caused by nitrous oxide.5The Maldives faces the threat of extinction from rising sea levels, but the government said on Thursday it was looking to the future with plans to build homes and a golf course that float.An increase in sea levels of just 18 to 59 centimeters would make the Maldives—a nation of tiny coral islands in the Indian Ocean—virtually uninhabitable by 2100, the UN’s climate change panel has warned.President Mohamed Nasheed has vowed a fight for survival, and last month he signed a deal with a Dutch company to study proposals for a floating structure that could support a conference centre, homes and an 18-hole golf course.“It is still early stages and we are awaiting a report on the practicality,” a government official who declined to be named said.The company, Dutch Docklands, is currently building floating developments in the Netherlands and Dubai. There was no immediate comment from the firm but its website said it undertook projects that make “land from water by providing large-scale floating constructions to create similar conditions as on land”.The Maldives began to work on an artificial island known as the Hulhumale near the crowded capital island of Male in 1997 and more than 30,000 people have been settled there to ease congestion. The city, which has a population of 100,000, is already protected from rising sea levels by a 30-million-dollar sea wall, and the government is considering increasingly imaginative ways to combat climate change.Nasheed, who staged the world’s first underwater cabinet meeting in October to highlight his people’s serious and difficult situation, has even spoken of buying land elsewhere in the world to enable Maldivians to relocate if their homes arecompleted covered.He has also promised to turn his nation into a model for the rest of the world by becoming “carbon neutral” by 2020. His plan involves ending fossil fuel use and powering all vehicles and buildings from “green” sources such as burning coconut husks.1. Why do you think Mohamed Nasheed chose Dutch Docklands?A. Because it has experience in building floating structure.B. Because it has a good fame throughout the world.C. Because it charged much less than other companies.D. Because it supports building floating structures in the world.2. The Hulhumale was built with the purpose of.A. attracting more visitorsB. making it a new capitalC. making the capital less crowdedD. fighting against climate change3. According to the last two paragraphs, Nasheed is a person who.A. has succeeded in buying land abroadB. is more than well-knownC. has thought more for his nationD. has stopped using fossil fuel4. The underlined word “vowed” in paragraph 3 can be replaced by.A. endedB. promisedC. failedD. weighed6PLAYA GRANDE, COSTA RICA? This resort town was long known for Leatherback Sea Turtle (棱皮龟) national Park, nightly turtle beach tours and even a sea turtle museum. However, on a beach where dozens of turtles used to nest on a given night, scientists spied only 32 leatherbacks all of last year.With leatherbacks threatened with extinction (灭绝), Playa Grande’s turtle museum was abandoned three years ago andnow sits among a sea of weeds. And the beachside ticket office for turtle tours was washed away by a high tide in September. “We do not promote that as a turtle tourism destination any more because we realize there are far too few turtles to please,” said Alvaro Fonseca, a park ranger (管理员).Even before scientists found temperatures going up over the past decade, sea turtles were threatened by beach development, drift net fishing and Costa Ricans interest in eating turtle eggs. But climate change may cause the most serious harm to an animal that has lived in the Pacific for 150 million years.Sea turtles are sensitive to numerous effects of warming. They feed on reefs, which are dying in hotter seas. They lay eggs on beaches that are being covered by rising seas and more violent waves.More uniquely their gender (性别) is determined, not by genes but by the egg’s temperature during development. Small rises in beach temperatures can result in ail-female populations, obviously problematic for survival. If the sand around the eggs hits 30 degrees Celsius, the gender balance shits to females: at about 32 degrees they are all female. Above 34, you get boiledeggs.On some nesting beaches, scientists are artificially cooling nests with shade or irrigation and trying to protect broader areas of coastal property from development to ensure that turtles have a place to nest as the seas rise.5. Why does the resort town stop promoting it’s turtle tourism?A. It decide s not to disturb the turtles’ normal life.B. Tourists have lost interest in watching turtles.C. There are only very few turtles now.D. The turtle museum was destroyed by a high tide.6. Which of the following is the major factor in the turtles endangerment?A. The locals eating habit.B. Drift net fishing.C. Beach development.D. Global warming.7. We learn from the last paragraph that scientists.A. are doing research on the sea riseB. are moving turtles to new homesC. are protecting turtle s’ nestsD. are getting rid of sea weeds8. The passage intends to.A. introduce a special kind of sea turtleB. explain the mystery of turtles’ eggsC. show the dangers a certain kind of turtle is facingD. attract more visitors to a sea turtle museum7Sometimes, the simplest ideas are the best. For example, to absorb heat from the sun to heat water, you need large, flat, black surfaces. One way to do that is to build those surfaces specially, on the roofs of buildings. But why go to all that trouble when cities are full of black surfaces already, in the form of asphalt(柏油) roads?Ten years ago, this thought came into the mind of Arian de Bondt, a Dutch engineer. He finally persuaded his boss to follow it up. The result is that their building is now heated in winter and cooled in summer by a system that relies on the surface of the road outside.The heat-collector is a system of connected water pipes. Most of them run from one side of the street to the other, just under the asphalt road. Some, however, dive deep into the ground. When the street surface gets hot in summer, water pumped through the pipes picks up this heat and takes it underground through one of the diving pipes. At a depth of 100 metres lies a natural aquifer(蓄水层) into which several heat exchangers(交换器) have been built. The hot water from the street runs through these exchangers, warming the ground-water, before returning to the surface through another pipe. The aquifer is thus used as a heat store.In winter, the working system is changed slightly. Water is pumped through the heat exchangers to pick up the heat stored during summer. This water goes into the building and is used to warm the place up. After performing that task, it is pumpedunder the asphalt and its remaining heat keeps the road free of snow and ice.1. Which of the following is true according to the first two paragraphs?A. Arian de Bondt got his idea from his boss.B. Large, flat, black surfaces need to be built in cities.C. The Dutch engineer’s system has been wide ly used.D. Heat can also be collected from asphalt roads.2. For what purpose are the diving pipes used?A. To absorb heat from the sun.B. To store heat for future use.C. To turn solar energy into heat energy.D. To carry heat down below the surface.3. From the last paragraph we can learn that.A. some pipes have to be re-arranged in winterB. the system can do more than warming up the buildingC. the exchangers will pick up heat from the street surfaceD. less heat may be collected in winter than in summer4. What is most likely to be discussed in the paragraph that follows?A. What we shall do if the system goes wrong.B. What we shall do if there are no asphalt roads.C. How the system cools the building in summer.D. How the system collects heat in spring and autumn.8We already know the fastest, least expensive way to slow climate change:Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets.Not long ago, my wife, PJ, and I tried a new diet—not to lose a little weight but to answer an annoying question about climate change. Scientists have reported recently that the world is heating up even faster than predicted only a few years ago, andthat the consequences could be severe if we don’t keep reducing emissions(排放) of carbon dioxide(CO2) and other greenhouse gases that are trapping heat in our atmosphere. We decided to try an experiment. For one month we recorded our personal emissions of CO2. We wanted to see how much we could cut back, so we went on a strict diet. The average US household(家庭) produces about 150 pounds of CO2 a day by doing common-place things like turning on air-conditioning or driving cars. That’s more than twice the European average and almost five times the global average, mostly because Americans drive more and have bigger houses. But how much should we try to reduce?For an answer, I checked with Tim Flannery, author of The Weather Makers: How Man Is Changing the Climate and What It Means for Life on Earth. In his book, he had challenged readers to make deep cuts in personal emissions to keep the world from reaching extremely important tipping points, such as the melting(融化) of the ice sheets in Greenland or West Antarctica. “To stay below that point, we need to reduce CO2 emissions by 80 percent, “ he said.Good advice, I thought. I’d opened our bedroom windows to let in the wind. We’d gotten so used to keeping our air-conditioning going around the clock. I’d almost forgotten the windows even opened. We should not let this happen again. It’s time for us to change our habits if necessary.1. Why did the author and his wife try a new diet?A. To take special kinds of food.B. To respond to climate change.C. To lose weight.D. To improve their health.2. The underlined words “tipping points” most probably refer to “”.A. freezing pointsB. burning pointsC. melting pointsD. boiling points3. It can be inferred from the passage that.A. it is necessary to keep the air-conditioning on all the timeB. it seems possible for every household to cut emissions ofCO2C. the average US household produces about 3, 000 pounds of CO2 a monthD. the average European household produces about 1, 000 pounds of CO2 a month4. Which of the following would be the best title for this passage?A. Saving Energy Starts at HomeB. Changing Our Habits Begins at WorkC. Changing Climate Sounds ReasonableD. Reducing Emissions of CO2 Proves Difficult9The need to feed a growing population is putting much pressure on the world’s supply of water. With 97% of the world’s w ater too salty to be drunk or used in agriculture, the worldwide supply of water needs careful management, especially in agriculture. Although the idea of a water shortage (短缺) seems strange to someone fortunate enough to live in ahigh rainfall country, many of the world’s agricultural industries experience constant water shortages.Although dams can be built to store water for agricultural use in dry areas and dry seasons, the costs of water redistribution (重新分配) are very high. Not only is there the cost of the engineering itself, but there is also an environmental cost to be considered. Where valleys (山谷) are flooded to create dams, houses are lost and wildlife homes destroyed. Besides, water may flow easily through pipes to fields, but it cannot be transported from one side of the world to the other. Each country must therefore rely on the management of its own water to supply its farming requirements.This is particularly troubling for countries with agricultural industries in areas dependent on irrigation (灌溉). In Texas, farmers’ overuse of irrgation water has resulted in a 25% reduction of the water stores. In the Central Valley area of southwestern USA, a huge water engineering project provided water for farming in dry valleys, but much of the water use has been poorly managed.Saudi Arabia’s attempts to grow wheat in desert areas haveseen the pumping of huge quantities of irrigation water from underground reserves. Because there is no rainfall in these areas, such reserves can only decrease, and it is believed that fifty years of pumping will see them run dry.1. From the first two paragraphs we learn that.A. much of the world’s water is availa ble for useB. people in high rainfall countries feel luckyC. the costs of water redistribution should be consideredD. water can be easily carried through pipes across the world2. Which of the following is true?A. The water stores in Texas have been reduced by 75%.B. Most industries in the world suffer from water shortages.C. The underground water in Saudi Arabia might run out in 50 years.D. Good management of water use resulted from the project in the Central Valley.3. What is most likely to be discussed in the paragraph thatfollows?A. Steps to improving water use management.B. Ways to reduce the costs of building dams.C. Measures to deal with worldwide water shortages.D. Approaches to handling the pressure on water supply.4. The text is mainly about.A. water supply and increasing populationB. water use management and agricultureC. water redistribution and wildlife protectionD. water shortages and environmental protection10Businesses are witnessing a difficult time, which has in turn produced influence on consumers’ desire to go green. However, shoppers are still laying stress on environmental concerns.Two thirds of customers say that environmental considerationsinform their purchases to the same degree as they did a year ago, while more than a quarter say that they are now even better aware of the environmental effect on what they buy. This may help to influence how shops store goods on their shelves. And the companies should still make efforts to become more environmentally friendly. Two out of three people think it is important to buy from environmentally responsible companies, with about one in seven saying that they had even decided to take their custom elsewhere if they felt a company’s environmental reputation was not good enough.Harry Morrison, chief executive (主管) of the Carbon Trust, sympathizes:“I understand this situation where survival is very important now. But from environmental considerations, the clock is ticking—we don’t have much time. In addition, cutting carbon has an immediate effect as costs drop and a medium-term benefit for the brand.”Larger companies have an extra motivation to look at reducing their carbon footprint, as new rules next year will require businesses to buy carbon allowances to make up for theiremissions (排放). Those that have taken early action will have a head start. More than two thirds of consumers are not clear about which companies are environmentally responsible. This suggests that firms that are able to relay clearly their message to the public will be in a pole position to attract shoppers.The Carbon Trust believes that it can help by informing customers about the good work companies are doing. “When companies are granted (授予) the standard, they can use a logo (标识) in all their marketing which makes it clear that they are working towards cutting emissions,” Mr. Morrison said.1. What’s the main idea of the passage?A. Businesses are finding ways to send their message to the shoppers.B. Companies will soon get information about cutting carbon emissions.C. Firms are making efforts to encourage customers to keep goods at home.D. Firms are urged to cut carbon emissions by shoppers’ environmental awareness.。