雪梨枇杷果酒主发酵工艺优化及挥发性成分分析

采用雪梨和枇杷作为原材料,探讨雪梨枇杷复合果酒主发酵的最佳工艺条件。以酒精度、pH、总酸、透光率、还原糖和感官评价为指标,通过单因素实验和正交试验确定雪梨与枇杷体积比、酵母接种量、SO₂添加量,对成品进行微生物指标的测定,并且利用顶空固相微萃取结合GC-MS分析雪梨枇杷果酒中挥发性成分种类以及相对含量。结果表明,以雪梨和枇杷为原料进行发酵,雪梨枇杷体积比为6:4,发酵原浆初始pH为3.5,SO₂添加量为80 mg/L,酵母接种量为0.4 g/L,5 d发酵结束后,得到果酒酒精度为9.51%vol,透光率达到91.5%,总酸为7.60 g/L,pH为3.56,还原糖为8.32 g/L,在此工艺条件下发酵果酒感官评价得分为91分,各因素对果酒酒精度影响次序为:初始pH > 酵母接种量 > 雪梨枇杷体积比 > SO₂添加量。并且测得该雪梨枇杷复合果酒的菌群总数为11 CFU/mL以及大肠菌群数小于10-9MPN/mL,均符合标准。通过分析其挥发性成分,雪梨枇杷果酒共检测出30种挥发性化合物,相对含量较高的为醇类和酯类,占总挥发性成分的87.82%,对果酒的香味起着积极作用。

Optimization of Main Fermentation Technology and Volatile Components Analysis of Snow Pear Loquat Wine

Using pear and loquat fruit as raw materials,the optimum conditions for the main fermentation of snow pear and loquat fruit wine were discussed in this study.Based on alcohol,pH,total acid,light transmittance,reducing sugar and sensory evaluation,the ratio of snow pear and loquat fruit,the addition of yeast inoculum and SO₂ were optimized by single factor experiment and orthogonal experiment. And the microbiological index of the finished product was determined.Further,the volatile components of snow pear and loquat fruit wine were analyzed by headspace solid phase microextraction combined with GC-MS analysis. The results showed that when the main fermentation was carried out with snow pear and loquat fruit as raw materials,the optimization resultsfor the volume ratio of snow pear and loquat fruit was 6∶4,the initial pH of the fermentation broth was 3.5,the addition amount of SO₂ was 80 mg/L,and the inoculation amount of yeast was 0.4 g/L. After 5days of fermentation,the alcohol content of the wine was 9.51%vol,the light transmittance was 91.5%,the total acid was 7.60 g/L,the pH value was 3.56,and the reducing sugar was 8.32 g/L. The fermented wine sensory evaluation score was 91 points under the optimal condition.The influence of various factors on the alcohol degree of fruit wine was:the initial pH>yeast inoculation amount>snow pear and loquat fruit volume ratio>SO₂ addition amount. The total bacterial flora of snow pear and loquat fruit wine was 11 CFU/mL and the coliform flora was less than 10-9 MPN/mL,which were all in line with the standard. By analyzing its volatile components,30 volatile compounds were detected in snow pear and loquat fruit wine,with alcohol and esters accounting for 87.82% of the total volatile components,which played a positive role in the flavor of fruit wine.