饼干感官品质评价的研究现状

饼干感官品质评价的研究现状
摘要：饼干的感官品质是由于力学特性、几何特性等物理化学性质的共同作用得到的复合性质。

本文在已有的研究基础上，总结了饼干感官品质的评价方法以及影响因素，并展望了发展趋势，以期对以后饼干的品质改善提供参考。

关键词：饼干；品质；评价；质地
1.饼干及其分类
饼干是以小麦粉为主要原料，加入(或不加入)糖，油脂及其他原料，经调粉(或调浆)、成型、烘烤(或煎烤)等工艺制成的口感酥松或松脆的食品。

饼干属于西方食品，机制饼干生产线于1930年初引进我国。

近年来，随着技术发展及人民生活水平的提高，中国的饼干行业快速发展，并且其市场潜力不可低估。

根据加工工艺的不同将饼干分为13类，包括酥性饼干、韧性饼干、发酵饼干、压缩饼干、曲奇饼干、夹心饼干、威化饼干、蛋圆饼干、蛋卷、煎饼、装饰饼干、水泡饼干及其他饼干。

饼干制作过程一般包括配料、调粉、辊轧、成型和烘烤等工序。

2.饼干的品质评价
2.1 饼干品质评价的指标及测定
饼干品质评价指标包括直径(Width，W)、厚度(Thickness，T)以及延展因子(spread factor，W/T)。

饼干直径值越大、厚度值越小，表示饼干质量越好。

由于饼干直径与厚度呈高度负相关，因此，常以直径表示饼干品质的优劣。

有时也对反映饼干酥脆性的表面裂纹多少和深度(表面纹理)以及硬度进行评价。

饼干表面裂纹浅、少，则表明该面粉不适合饼干烘焙。

AACC方法要求饼干出炉冷却到室温，将6块(或2块)饼干边缘对边缘测量其直径，各饼干皆按一个方向转动900，重复4次，并计算平均值。

厚度的测量是将饼干叠起，测量其高度，随意变换饼干位置，重复测量，计算平均值。

2.2 饼干的质地评价
1963年，首先由Brandt提出了质地多面剖析法(Texture ProfileAnalysis，TPA)的概念。

这种方法把对质地的表现用语，即感官知觉与其力学性质、几何特性结合起来进行了定义，使得对质地的感官评价信息可以用客观的方法相互勾通或传
递。

TPA质构测试又被称为两次咀嚼测试，主要是通过模拟人口腔的咀嚼运动，对样品进行两次压缩，测试与微机连接，通过界面输出质构测试曲线。

目前测定饼干的质地主要使用质构仪。

质构仪主要包括测试主机、控制台、备用探头和通过附件以及与质构仪相配套的专用软件，它对距离、时间、作用力三者及其相互关系的处理，获得对饼干面团流变特性最大拉伸阻力、拉伸比、面团黏性、面团强度等参数的测试结果以及饼干的嫩度、硬度、脆性、黏性、弹性、咀嚼性、拉伸强度、抗压强度、穿透强度、内聚性、黏附性、松弛性、恢复度、破坏强度、张力、断裂强度、破裂点、剥离强度、铺展性等等。

饼干一般常用圆柱形探头，P50探头，测试前速率1.00mm/s，测试速率0.50mm/s，测试后的速率0.5mm/s，压缩程度90%，数据采集速率为200p/s；蛋糕，采用P25探头，
测试前的速率为5mm/s，测试时的速率为2mm/s，测试后速率下压距离为5mm，两次压缩间隔时间为2s。

3.影响饼干品质的因素
3.1饼干面团对饼干品质的影晌
饼干的品质主要受饼干面团的影响，饼干面团的成分及工艺过程共同影响着饼干的品质。

3.1.1饼干面团成分对饼干质地及流变学特性的影响
饼干面团的成分是影响饼干品质的内在重要因素。

目前市场上有很多种口味的饼干，其在饼干面团中添加的成分都是不同的，从而导致其质地也有很大区别。

马栋等人研究发现，在面粉中直接添加大豆粉不能使面粉白度增加，随着大豆粉添加量的增大，面粉白度降低；在面粉中添加大豆粉后其面糊色度也有所降低。

在面粉中添加脱脂豆粉后，在添加比例<3%的情况下，可明显提高面团的形成时间和稳定时间，使面粉的筋力增强，对面粉具有较好的改良作用。

当添加量>3%以后，大豆粉对面团有不良影响。

M.L.Sudha等人研究发现，随着脂肪含量的降低，饼干面团的硬度在增加。

同时通过RWAM方法，淀粉测定记录仪和质地分析仪分析，当脂肪含量从20%降低到6%时，面团挤压时间也从43s增加到167s，面团的黏度从180BU增加到540BU，面团的硬度从20.78N增加到44.08N。

然而在生产低脂饼干中用于取代脂肪的麦芽糊精和聚葡萄糖却能在一定程度上增加饼干面团的硬度和黏度。

此外甘油单硬脂肪酸和瓜尔豆胶也对面团的黏度和硬
度产生了积极影响。

研究还发现当用麦芽糊精取代脂肪的时候，饼干的质地会有明显的改善。

当甘油单硬脂酸或瓜尔豆胶与麦芽糊精一起使用时，饼干的质地会进一步的提高。

P.Fustie等人研究发现，在面团的流变学参数和饼干的质地之间存在着必然的联系，而通过定量面团中可溶性和不可溶性的蛋白质、戊聚糖、来测定面团的黏稠度、伸长黏度、硬度、半松弛时间、连续松弛的速率、黏结性和弹性，从而来控制饼干空间上和组织上的特性。

结果显示，面团中蛋白质和戊聚搪含量越高，烘烤出的饼干越坚硬，越不易碎。

加入合适的乳化剂可增强面团的弹性，韧性和持水性。

王显伦等人在面粉中添加乳化剂试验中发现，在面粉中加入SSL离子乳化剂，可提高面团吸水量，有效降低饼干面皮的黏度，提高饼干的膨松度及感官品质。

而添加酶也会对面团的流变性有重要的影响。

周素梅等人研究了戊聚糖酶(Pentopan)、葡萄糖氧化酶(Gox)以及脂肪氧合酶(活性大豆粉，SF)对普通粉和专用粉面团流变性质的影响。

结果表明:酶对不同品种面粉的面团吸水量的影响不同，对普通粉影响最大的是Gox；对专用粉影响最大的是Pentopan，Pentopan降低了面团中的弹性成分，Gox使弹性成分增加，SF则对专用粉的影响较大。

3.1.2饼干面团的工艺过程对饼干质地及流变学特性的影响
在饼干的制作工艺中，面团的处理是最关键的一步。

对面团不同的处理方式，都会对面团的流变性和饼干的质地产生很大的影响。

R.Sai Manohar等人研究发现，当面团的混合时间达到180s时，烤制出的饼干质地最佳。

因为面团的流变性跟蛋白质的含量有很大关系，如果加入二硫键裂解剂、半胱氨酸、二硫赤鲜糖醇等改善面团蛋白质的添加剂，能够减少揉面团的时间，增加面团的黏结性。

而在由小麦面粉中制成的面团中加入半胱氨酸和二硫赤鲜糖醇，烘烤出的饼干会更脆。

M.C.Peck等人研究了滚揉的条件对饼干面团流变性和饼干的质地的影响，确定了滚揉面团的最佳工艺。

3.2饼干的成分对饼干品质的影晌
近年来，人们对饼干的要求已经不限于滋味与口感，更注重吃出健康，所以无糖、低卡路里、高纤维的饼干越来越受欢迎。

M.LSudha等人研究发现，在饼干制作中添加小麦糠、燕麦糠、大麦糠可以有效改善饼干的断裂强度，饼干硬度增加，不易碎，虽然色泽变暗，表面光滑程度有所降低，但是增加了饼干中的食
用纤维，从而促进人体吸收。

结果表明，添加的最佳比例是小麦糠20%、燕麦糠30%、大麦糠20%，这种饼干是最能得到消费者认可的。

饼干中的脂肪对饼干的品质也有很大影响。

Jissy Jacob等人研究了在饼干制作过程中，添加4种不同类型的脂类对饼干品质的影响。

他分别选用了有乳化效应的酥油、有乳化效应的人造黄油、没有乳化效应的蔬菜氢化油脂和葵花籽油。

结果发现，添加葵花籽油后，饼干会有更高的延展性，更大的断裂强度；而添加入造黄油和酥油，饼干的延展性和断裂强度相似；而添加氢化油脂后，饼干的延展性显著降低，断裂强度也不如葵花籽油的效果。

在饼干制作过程中，由于适口性需要，用糖类做甜味剂。

而糖类对饼干的品质也有很大的影响。

适量的糖可以使饼干具有酥脆的口感，同时糖也影响饼干的扩展程度。

周翠英研究了低聚木糖在饼千生产过程中的应用。

试验证明，随着低聚木糖添加量的增加，饼干的颜色加深，硬度增强。

综合各方面因素考虑，当低聚木糖的添加量在 2.5%的时候，饼干层次分明，表面平滑光亮，香味浓郁，口感松脆适当，品质最佳。

4.对饼干品质研究的展望
饼干品质分析是测量关于饼干口感的属性的方法，其测定评价方法有感官评定和仪器分析。

饼干品质的感官评价，不仅需要具有一定判断能力的评审员，而且这种评价鉴定往往费时费力。

其结果也常受多种因素影响，很不稳定。

因此，能够正确表现饼干品质的客观评价方法在这些方面具有较大的优势。

但对于饼干品质的评价(比如TPA测试)来说，它却很难通过感官评定来表现饼干品质的综合力学性质。

例如柔软度等。

很难用某一种单纯的力学性质表达。

因此，饼干品质的测定仪器多属于半经验或模拟测定。

所以感官评定作为品质测试方法仍然是不可或缺的方法。

所以应该建立一套行之有效的客观评价质地的方法，开发出一系列适合于不同类型饼干的综合评价的测试参数的评价指标是摆在我们而前急待解决的问题。

随着物性测试仪的推广应用，随着人们对感官评价进行客观评价分析的认识的深人，越来越多的物性测试仪参数和感官指标将会建立起来。

这对于改善饼干品质，提高饼干质量安全具有很重要的意义。

参考文献：
1.AACC.(2002).Approved methods of the AACC (10th ed).St.Paul,MN:American Association of Cereal Chemisits (Methods 08-01,30-25,44-15A,46-10,54-21).
2.吴洪华,姜松. 食品质地及其TPA测试[J]. 食品研究与开发,2005,26:128~129.
3.孙彩玲. TPA质构分析模式在食品研究中的应用[J].试验科学与技术，2007(2):1~3.
4.马栋,郑学玲. 大豆粉对面粉理化品质影响研究[J].面粉通讯，2006 (l):32~37.
5.M.C.Peck, S.L.Rough. Roller extrusion of biscuit doughs[J]. Journal of Food Engineering,2006(74):431~450.
6.王显伦,李葱娟. SSL对饼干生产影响研究[J].食品科技，2006，(4):38~40.
7.周素梅,王球,许时耍. 戊聚糖酶与氧化酶对面团流变性质影响的研究[J].研究与探讨,2002,23(8):16~18.
8.周翠英.低聚木搪在饼干生产中的应用研究[J]. 食品科技,2006,(11):149~151.
9.Shogren R L, Mohamed A A, Carriere C J. Sensory analysis of whole wheat/soy flour blends[J]. Journal of Food Science, 2003,68:2141~2145.
10.Gaines,C.S.,Kassuba,A.,Finney P.L.1992a.Instrumental measurement of cookie hardness.I.assessment of methods[J].Cereal Chemistry,69:115~119.
11.Jissy Jacob,K.Leelavathi. Effect of fat-type on cookie dough and cookie quality[J]. Food Chemistry,2007(79):299~305.
12.Zheng Tie-song. Studies on Application of Texture Analyzer to the quality Evaluation of Dough and Bread [J].Food Science,2004,25(10):37~40.
附件
5.M.C.Peck, S.L.Rough. Roller extrusion of biscuit doughs[J]. Journal of Food Engineering,2006(74):431~450.
Abstract: Biscuit doughs are dense solid–liquid pastes which exhibit complex rheological behaviour. The rolling behaviour of sheets of commercial short and hard biscuit doughs was investigated using an instrumented counter-rotating roll mill, which allowed the roll torque, separating force and surface pressure to be monitored. The rheological characteristics of the two doughs were quantified by analysing data from ram extrusion experiments in terms of a
quasi-plastic model (following the Benbow–Bridgwater approach) and a power law fluid model. The results indicated that the doughs were not ideally suited to the quasi-plastic analysis. The power law parameters varied noticeably between the doughs but both were strongly shear-thinning (power law shear indices of 0.25 and 0.5), with large extensional viscosities. These rheological model parameters were subsequently used to generate predictions of dough behaviour during rolling. A standard sheet metal plasticity model was modified to include strain rate dependency but neither dough’s behaviour could be adequately described by this model. The power law fluid approach based on the lubrication assumption reported by Levine tended to underpredict the work requirement owing to the significant contribution from extensional deformation. Interestingly, the system could be modelled in terms of an apparent power law rheology by fitting data to Levine’s model. Better agreement was obtained for some parameters but not consistently so, indicating that the power law approach is not adequate for these soft-solid materials.
Keywords: Dough; Plasticity model; Power law fluid; Rolling
9.Shogren R L, Mohamed A A, Carriere C J. Sensory analysis of whole wheat/soy flour blends[J]. Journal of Food Science, 2003,68:2141~2145.
Abstract: Breads containing 0% to 40% defatted soy flour, 35% to 100% whole wheat flour, and 0% to 35% white bread flour were prepared. Beany or bitter flavor ratings for the yeast-leavened breads containing up to 30% soy flour were not significantly different from the control whole wheat bread. A high-quality yeast was the most important factor in reducing the beany taste of the bread. Addition of ascorbic acid significantly increased yeasty flavor, and there was a strong inverse correlation between beany and sweet flavors. These studies suggest that an appealing, nutritious bread containing up to 30% to 40% soy flour can be prepared in an easy and economical manner using equipment available in home or institutional kitchens.
Keywords: bread; soy flour; whole wheat; sensory; taste
10.Gaines,C.S.,Kassuba,A.,Finney P.L.1992a.Instrumental measurement of cookie hardness.I.assessment of methods[J].Cereal Chem.69:115~119.
Abstract: Probing and a three-point bread technique for instrumental measurement of cookie hardness were appraised. Both techniques were used to evaluate the hardness of cookies produced by there laboratory formulations:the AACC micromethod and macromethod for sugar-snap cookies and a new commercial for wire-cut cookies. The
three formulas differ in their ratios of sugar, shortening, and water. Both instrumental and sensory measurements indicated that wire-cut formula cookies were the least hard of the three formulation. The three-point break technique measured both hardness and brittleness, but the probe technique required less product. Probing was used to assess differeces among four wheat cultivars and effects of postbake age on cookies hardness. Least significant differences and variances for probing data(as a percentage of the range of hardness observed with the four cultivars) were usually smallest for the wire-cut formula cookies.
11.Jissy Jacob,K.Leelavathi. Effect of fat-type on cookie dough and cookie quality[J]. Food Chemistry,2007(79):299~305.
Abstract: Effect of four different fat types on the rheology of the cookie dough and subsequently their effect on the quality of cookies were studied. The dough containing sunflower oil had the least initial farinograph consistency while that containing the bakery fat (‘marvo’) had the most consistency. Observation of the response of the above two cookies doughs to farinograph mixing showed that the one containing the oil showed more resistance to mixing while the other containing the bakery fat decreased in its consistency denoting the softer nature of the later. The cookies containing the oil had relatively higher spread value than the others. While the cookies containing the non-emulsified hydrogenated fat (‘dalda’) had the least spread. Studies also showed that the cookies containing the oil started to spread earlier and continued to spread for a longer time. Cookies containing oil had relatively harder texture and probably so because of the poor entrapment of air during creaming. However, the quality of these cookies was significantly improved by including 0.5% sodium steroyl lactylate in the formulation.
Keywords:Cookies; Shortening; Fat; Set-time; Cookie spread; Farinograph consistency
12.Zheng Tie-song. Studies on Application of Texture Analyzer to the quality Evaluation of Dough and Bread [J].Food Science,2004,25(10):37~40.
Abstract: Nine quality indexes of dough based on eight kinds of wheat flour have been measured with the Texture Analyzer in this paper. The nine indexes of dough were elasticity, adhesive force, adhesiveness, fracture force 1, 1st fracture work done, 1st fracture deformation, recoverable work done 1, and recoverable deformation 1. These quality indexes of dough with
bread quality (volume and elasticity change rate) and wheat flour characteristic were also studied by correlation analysis. The results showed that correlations between hardness, adhesive force with the volume of bread were significant. Their correlation coefficients were 0.546, 0.568, respectively. The correlation between elasticity and the volume of bread was negative, and the correlation coefficient was-0.606. The correlation between adhesive force and elasticity change rate of bread keeping at room temperature in 24 hours was significant, and the correlation coefficient was 0.707.The texture of dough and wheat flour characteristic had obvious correlation. Keywords: texture analyzer; dough bread; flour quality。