发酵型桑葚酒香气成分及澄清工艺的研究

发酵型桑葚酒香气成分及澄清工艺的研究

摘要

本试验以陕西“红果2号”桑葚为原料，通过筛选酿酒酵母，研究不同酵母（KD、RC212和K1）对桑葚酒香气成分的影响及KD酵母发酵桑葚酒在主发酵和后发酵结束后香气成分的变化；同时也研究了不同澄清剂对桑葚酒的澄清效果，以期为我国桑葚酒的工业化生产提供理论依据和技术支持。获得主要结论如下：

1. 在18℃～20℃条件下,对四种酵母（KD 、RC212、K1和Fermiblanc）进行发酵试验，通过测定发酵过程中发酵液的总糖量、相对密度和pH，以及原酒的酒精含量、总酸量、残糖量和挥发酸量，并对原酒风味进行感官评价，确定要选用的酵母。结果表明，KD酵母发酵速度快、产酸量低、产酒精率高、且原酒风味好，适合陕西“红果2号”桑葚酒的酿造。

2. 采用气相色谱-质谱联用技术（GC/MS）对三种发酵性能较好的酵母（KD 、RC212和K1）发酵所得桑葚酒的香气成分及KD酵母发酵桑葚酒在主发酵和后发酵结束后的香气成分进行分析。结果表明：

（1）酵母是影响桑葚酒香气形成的重要因素，不同酵母发酵所得桑葚酒的香气成分有很大差异。酵母KD发酵的桑葚酒中检测出28种香气成分，其主体成分为2，3-丁二醇、3-甲基-1-丁醇、苯乙醇，相对含量分别为38.23%、32.22%、2.87%；酵母RC212发酵的桑葚酒中检测出25种香气成分，其主体成分为1，2-苯甲酸，单（2-乙基己基）酯、3-甲基-1-丁醇、2，3-丁二醇，相对含量分别为81.70%、8.18%、4.77%；酵母K1发酵的桑葚酒中检测出23种香气成分，其主体成分为邻苯二甲酸二辛酯、3-甲基-1-丁醇、2，3-丁二醇，相对含量分别为28.27%、28.19%、22.89%。

（2）三种酵母发酵所得桑葚酒共检测出46种香气成分，其中有13种成分相同，它们是3-甲基-1-丁醇、2，3-丁二醇、3-甲基丁酸乙酯、苯乙醇等。这13种相同成分在KD、K1和RC212发酵所得桑葚酒的香气成分中的总相对含量分别为82%、62%、15%。

（3）KD酵母发酵所得桑葚酒的绝大部分香气成分在主发酵阶段产生，在后发酵阶段被平衡，同时在后发酵阶段也有新的香气成分产生。主发酵阶段检测出25种香气成分，其主体成分为3-甲基-1-丁醇、2，3-丁二醇、1，2-苯甲酸，单（2-乙基己基）酯，相对含量分别为42.55%、20.35%、8.07%；后发酵阶段检测出28种香气成分，其主体成分为2，3-丁二醇、3-甲基-1-丁醇、苯乙醇，相对含量分别为38.23%、32.22%、2.87%。其中有17种成分相同，总相对含量分别为81.55%和90.85%。桑葚酒在主发酵阶段产生的香气成分有8种在后发酵中消失，但同时又有11种新的香气成分产生。

3. 利用蛋清（OVO）、果胶酶（EX-V）、皂土（BGR）和聚乙烯聚吡咯烷酮（PVPP）四种单一澄清剂及三组复合澄清剂（PVPP+皂土、PVPP+蛋清、蛋清+皂土）对KD酵母发酵的桑葚酒进行澄清试验，通过对桑葚酒透光率的测定，比较其澄清效果。结果表明：

添加澄清剂澄清比自然澄清效果好。在室温条件下（20℃左右），单一澄清剂的最适添加量分别为：蛋清0.25g/L，果胶酶0.08g/L，皂土0.5g/L，PVPP0.15g/L。与其它三种单一澄清剂相比，PVPP的澄清效果最好，其最佳澄清条件为：PVPP为0.15g/L，pH3.3，温度20℃，处理24h以上。桑葚酒经PVPP处理后，透光率明显提高，酒体颜色发生显著变化，同时涩味减少，新鲜感及芳香味增强，而酒精度、残糖量和pH等理化指标均没有发生显著改变。复合澄清剂的最适添加量分别为：PVPP（0.14g/L）+皂土（0.10g/L），PVPP（0.12g/L）+蛋清（0.10g/L），蛋清（0.25g/L）+皂土（0.10g/L）。

本试验的创新点在于首次采用气相色谱-质谱联用技术（GC/MS）对桑葚酒的香气成分进行分析，较系统地研究了不同酵母对桑葚酒香气成分的影响及KD酵母发酵桑葚酒在主发酵和后发酵结束后香气成分的变化，明确了菌种是影响桑葚酒香气形成的重要因素，桑葚酒的绝大部分香气成分是在主发酵阶段产生；首次对桑葚酒澄清工艺进行研究，得出澄清剂PVPP澄清的最佳条件为：PVPP 0.15g/L，pH3.3，温度20℃，处理24h 以上。

关键词：桑葚酒；发酵；香气成分；澄清

THE STUDY ON AROMA COMPONENTS

AND CLARIFICATION TECHNOLOGY OF

FERMENTED MULBERRY WINE

ABSTRACT

In this paper ,influence to aroma components of mulberry wine fermented by different yeasts(KD、RC212、K1) through brewing yeasts selection, change of aroma components after primary fermentation and secondary fermentation of KD yeast, and effect of different clarifying agents on mulberry wine were studied with Shaan’xi red fruit No.2 as raw material. The aim is to give scientific support to industrial production of mulberry wine in our country. The following are the main results:

1.Fermentation experiments of four different active dry yeasts(KD、RC212、K1、fermiblanc) were undertaken at 18℃～20℃, according to sugar content ,relative density, pH of mulberry must during fermentation, and ethanol content, tartaric acid content,residual sugar content, volatile acid content of wine were determined ,and the flavor estimation of mulberry wine was carried out in order to select the suitable yeasts. The result indicated that KD yeast had the characteristics of rapid fermentation speed, low content of acid, high ratio of ethanol production and good flavor. KD was considered as suitable yeast for mulberry wine brewed by red fruit No.

2.

2. The analysis of gas chromatography / mass spectrometry (GC/MS) on aroma components of mulberry wine fermented by three yeasts (KD、RC212、K1) and aroma components of mulberry wine fermented by KD yeast after primary fermentation and secondary fermentation were undertaken, the results indicate:

(1) Yeasts play a very important role in aroma formation of fruit wine, there are different in aroma components of mulberry wines fermented by different yeasts. 28 aroma components of wine fermented by KD were detected, the main aroma components are 2,3-butanediol, 1-butanol,3-methyl, Phenylethylalcohol, their relative content are respectively 38.23%, 32.22%, 2.87%; 25 aroma components of RC212 were detected, the main components are 1,2-benzenedicarboxylicacid,mono(2-ethylhexyl)ester, 1-butanol,3-methyl, 2,3-butanediol, their relative content are respectively 81.70%, 8.18%, 4.77%; 23 aroma components of K1were detected, the main aroma components are di-n-octylphthalate, 1-butanol,3-methyl, 2, 3-butanediol, the relative content are respectively 28.27%, 28.19%, 22.89%.

(2) 13 similar aroma components among 46 aroma components were detected in three kinds of mulberry wine, they are 1-butanol,3-methyl, 2,3-butanediol, 1-butanol, 3-methyl-,acetate and so on. Total amount of similar components covered respectively