【作者】 吴连军；

【导师】 杜金华；

【作者基本信息】 山东农业大学 ， 农业推广， 2007， 硕士

【摘要】 石榴品种资源丰富、分布广、营养价值高、保健功能强,开发石榴酒不仅利于石榴的消费、增加产业值,而且符合发展果酒的产业政策。目前对石榴酒的研究尚不完善,工艺参数上多参照葡萄酒、缺少专用酵母、缺乏对酸石榴酒的研究,本文从SO₂、酵母及有机酸三个方面对石榴酒发酵进行了研究。主要研究结果如下:1将活化好果酒干酵母接入甜、酸石榴汁中,研究了添加60mg/L SO₂对甜Ⅰ、Ⅱ、酸Ⅲ石榴酒发酵的影响。SO₂对发酵过程中pH值、滴定酸几乎没影响:添加60mg/LSO₂能促进石榴汁发酵进程,影响程度依石榴品种有所差异,石榴汁的发酵速度受石榴成分的影响。挥发酸含量低的石榴酒其酒精度高、干浸出物也高。研究证实,试验中使用的果酒酵母（Saccharomyces cerevisiae sp.）在高酸环境中具有良好的发酵性能。2石榴汁（酒）中有机酸高效液相测定的最佳色谱条件为:色谱柱,Waters Atlantis dC18柱（4.6×250mm,5μm）;流动相0.02mol/L K₂HPO₄缓冲液（H₃PO₄调节为pH2.80）;流速0.7ml/mim柱温为30℃;检测波长为215nm。此条件下,线性回归方程的相关系数在0.9954～0.9999之间,检出限在0.0030～0.83mg/L之间,定量限在0.01～2.78mg/L之间,回收率测定在86.88～100.78%之间,精密度试验变异系数在0.7～6.6%之间。3石榴汁中有机酸包括草酸、乳酸、柠檬酸、苹果酸、α-酮戊二酸、乙酸、琥珀酸、葡萄糖酸、酒石酸、富马酸;其中甜石榴以乳酸、草酸和柠檬酸为主,分别占总有机酸含量的51.2～53.9%、26.8～28.8%和11.8～16.8%;酸石榴以柠檬酸、乳酸为主,分别占总有机酸含量的84.4%、14.0%。4接种Saccharomyces cerevisiae sp.后,石榴汁中有机酸组成、含量均发生变化。来自石榴汁中的草酸、苹果酸、柠檬酸、乳酸、乙酸均参与了酵母的有机酸代谢反应,且代谢程度依石榴原汁的有机酸组成、含量不同而有很大差异;丙酮酸、酒石酸、富马酸、琥珀酸则主要为发酵过程中酵母的代谢副产物。5 3株酿酒酵母（WY-1、WY-2、WY-3）和1株拜耳结合酵母（WY-4）作为供试菌株研究了其对酸石榴发酵规律、风味的影响和其降酸性能。酵母活化、扩培后作为种子液接入酸石榴汁,结果WY-1、WY-2、WY-3有相似的发酵特性,起酵后发酵速度快而平稳;WY-4起酵慢、发酵时间长;相对于拜耳结合酵母,3株酿酒酵母更能很好的适应酸石榴汁的高酸、低pH值环境。成品酒理化指标显示,4株酵母所酿的酸石榴酒其滴定酸、总糖、还原糖、挥发酸含量几乎没有差别;酒精度差别较大,综合看酿酒酵母产酒率高于拜耳结合酵母。石榴酒中除WY-2的干浸出物较原汁降低外,其余均增大。结合感官分析,WY-1酵母适合发酵酸石榴汁,且石榴酒风味最佳。4株酵母代谢酸石榴汁中主要有机酸柠檬酸没有显著差异（P＞0.05）,与柠檬酸下降了8.7～13.3%相对应,总有机酸含量下降了8.1～12.8%。更多还原

【Abstract】 Megranate wine is one of the most nutritional low alcohol beverages which is fermentative and healthy.In this research,SO₂,wine yeasts and organic acids were studied to understand the rclatation between them and fermented megranate wine.The main research results were as follows:1 Effects of Sulfur dioxide（SO₂） on the brewing of megranate juices from three varieties were studied,respectively.The results showed that:adding 60mg/L SO₂ did not affect pH value and acidity significantly during fermentation.The SO₂ could promote the fermentation of megranate juices whose fermentation speeds were influenced by megranate components.The finished wines with lower volatile acid had higher alcohol content and dry extract.And the results also indicated that the wine yeast（Saccharomyces cerevisiae sp.） used in this research possessed good brewing performance in higher acid circumstances.2 A reverse phase HPLC method for simultaneous determination of organic acids in megranate juices and wines was developed.Chromatogram columniations:Waters Atlantis dC18（4.6mm×250mm,5μm）;mobile phase: 0.02mol/L K₂HPO₄（adjusted to pH2.80 with phosphoric acid）;UV detector at 215nm;column temperature:30℃;flow-velocity:0.7 mL/min;sample size:15μL.There was a linear relationship between the contents of the standards organic acids and the peak area of the chromatogram chart with the R² value 0.9954～0.9999.The lowest detection level was 0.0030～0.83mg/L and the lowest quantity level 0.01～2.78mg/L,recovery was 86.88～100.78%and coefficients of variation 0.7～6.6%under the condition above.3 Oxalic,lactic,citric,malic,ketoglutaric,acetic,succinic,fumaric,tartaric and glueonic acids were found in megranate juices.The main organic acids were lactic acid（about 51.2～53.9%）,oxalic acid（about 26.8～28.8%）,and citric acid（about 11.8～16.8%） in sweet megranate juices,while citric acid （about 84.4%） and lactic acid（about 14%） were the main organic acids in acid megranate juices. 4 The composition and content of organic acids changed after inoculation of activity dry yeast into megranate juices.Oxalic,lactic,citric,malic and acetic acid originating from megranate juices participated in yeast metabolism and the level of their metabolism was influenced by content of organic acids in juices. Pyruvic,tartaric,fumaric and succinic acid were mainly produced by yeast during the fermentation.5 3 Saccharomyces cerevisiae（WY-1,WY-2,WY-3） and 1 Zygosaccharomyces bailii（WY-4） were selected as fermentation strains to study their effect on the brewing of acid megranate juices and flavor and their ability in metabolism of organic acids.The results showed that wine yeast WY-1,WY-2,WY-3 had the similar fermentation performance and they had rapid and steady fermentation speed,while WY-4 had longer lag phase and slower fermentation speed.3 Saccharomyces cerevisiae possessed good brewing performance in higher acid circumstances comparing to 1 Zygosaccharomyces bailii.In finished wine fermented by 4 wine yeast, titration acid,total sugar,residual sugar and volatile acid content had almost no difference,while alcohol content had significantly difference,which is Saccharomyces cerevisiae had higher alcohol yield than Zygosaccharomyces bailii.Dry extract content increased in wine fermented by WY-1,WY-3,WY-4 and that decreased by WY-2.Sensory evaluations showed that finished acid megranate wine with 1# had best flavor characteristic.The ability of degrade citric acid,which is mainly component in sour megranate juice,for 4 wine yeast has no significant difference（P＞0.05）.The total organic acid content decreased by 8.1～12.8%coinciding with citric acid decreasing by 8.7～13.3%.更多还原