Optimization Of Fermentation Technology Of Mulberry Rice Wine And Its Effect On Aroma Formation

Mulberry,which is abundant in China,is rich in anthocyanins,polysaccharides and other substances with high sugar content.Mulberry rice wine is an alcoholic drink fermented from mulberries and rice wine,which can improve the nutritional value of rice wine and the added value of mulberries and the rational utilization of mulberries resources was realized.In this paper,a kind of mulberry rice wine was developed based on the liquid fermentation process of rice wine,and the liquefaction process,saccharification process,fermentation process and clarification process of rice wine were studied.Then the headspace solid phase microextraction(HS-SPME)technique and GC-MS technique were used to analyze the effects of fermentation process and clarification treatment on the aroma formation of rice wine.The main results were as follows:(1)The liquefaction and saccharification process of rice was studied and the best liquefaction process was as follows:gelatinization treatment for 60 min,a-amylase addition amount 70 p/g,liquefaction time 60 min,liquefaction temperature 60 ?,and rice liquefaction DE value reached 18.5%.Further saccharification of liquefied mash was carried out to obtain the optimal saccharification process:saccharification temperature 60 ?,saccharification time 16 h,saccharification enzyme addition amount 80?/g,saccharification pH value 4.5,and the reducing sugar content of mash was 184.3 g/L.(2)Based on the single factor experiment,the fermentation process of mulberry rice wine was optimized by response surface experiment.The optimum fermentation technology was as follows:mulberry juice addition amount 20%,fermentation temperature 21.5 ?,yeast inoculum volume 3 ‰,fermentation time 20 d.On this basis,the mixed fermentation process of mulberry rice wine was further studied.The optimum mixed fermentation technology was as follows:Inoculation of Saccharomyces Cerevisiae for 7 days and then inoculation of active wine dry yeast.The finished rice wine has an alcohol content of 10.1%vol,total sugar 30.7 g/L,total acid 6.85 g/L,and sensory score of 89.6 points.The color of the rice wine was orange red,the taste was mellow and the aroma was rich.The aroma components in the fermented mulberry wines of different fermentation methods were analyzed.The results showed that the fermentation method of inoculation of Saccharomyces Cerevisiae for 7 days and then inoculation of active wine dry yeast can increase the relative content of alcohols in rice wine.The main component analysis of the main aroma components was carried out by combining the relative odor activity value(ROAV)of the aroma components in the mulberry rice wine.The results showed that the aroma components of the mulberry rice wine which was inoculated of Saccharomyces Cerevisiae for 7 d and then inoculation of active wine dry yeast were obviously gathered.The aroma of the rice wine was rich,fruity and milky.The relative content of P-phenylethyl alcohol in rice wine was 2.63-3.96 times higher than other fermentation methods.(3)In the experiment,bentonite and chitosan were used as composite clarifying agent to clarify rice wine.The best clarification process was as follows:composite ratio(saponin:chitosan)1:2.6,water bath temperature 39?,water bath time 41 min,Under this process condition,the light transmittance of mulberry rice wine reached 95.6%.Analysis of aroma substances of mulberry rice wines that have been clarified and unclarified.The results showed that 38 and 49 aromatic substances were detected in clarified mulberry rice wine and unclarified mulberry rice wine,respectively.However,the esters and alcohols in the rice wine after clarification are basically retained and the relative content was increased,the impurities such as hydrocarbons and phenols were reduced,the aroma components in the rice wine were more coordinated,and the aroma of the wine was more intense and heavy.