| Yellow rice wine is a kind of low-alcohol wine with full-bodied flavor and high nutritional value,which is made from rice as raw material by soaking rice,cooking,saccharification and fermentation,etc.It is one of the beverage wines with a long history in China.Setaria itatica is one of the ancient cultivated crops in China.Millet is the product of milling it,rich in all kinds of nutrients with appropriate proportion and high digestibility,which is a good source of nutrition.In addition to carbohydrates,the content of protein,fat,minerals and vitamins of millet are higher than that of rice and corn,which is the leader of similar food crops.Millet yellow pigment is a unique active ingredient of millet.It not only has the function of protecting vision and epithelial cells,but also can improve human immunity,quench excessive free radicals in the body,prevent and treat a variety of cancers.At the same time,it also has a good effect on oral ulcers,skin diseases,etc.Brewing rice wine with millet as raw material can not only improve the nutritional value and appearance of rice wine,but also increase millet added value by rational use of millet resources.This article use millet as raw material,to explore the nutrition ingredients and brewing characteristics of different varieties of millet,based on response surface methodology and sensory evaluation,to optimize raw materials soaking and saccharification conditions,to select millet rice wine fermentation strains and optimize fermentation process parameters.And the basic physical and chemical properties,volatile flavor components and ethyl carbamate content of millet wines brewed by different kinds of millet has been studied by comparative analysis,aiming at the development of a good quality,nutritional and healthy millet wine,providing theoretical basis and technical support for millet rice wine production.The main research conclusions are as follows:(1)Based on the comparative analysis of basic nutrition ingredients content and brewing characteristics of 10 varieties of millet,and the determination of millet yellow pigment content,it is concluded that Gold 1,Jingu 21,Red Millet,Xiaoxianggu and Dajinmiao are suitable for millet rice wine brewing,considering their composition and characteristics.While the millet yellow pigment content of Red Millet is too low to meet research expectations.And although the lipids content of Oriental Bright is relatively high,its millet yellow pigment content is significantly higher than other varieties.Therefore,based on the comprehensive analysis,we can select Gold 1,Jingu 21,Xiaoxianggu,Dajinmiao and Oriental Bright as the raw materials of millet wine for further fermentation experiment.(2)In order to solve the problem of millet's high fat and protein content as a raw material for rice wine brewing,the influence of milling degree of millet on the basic nutrients and yellow pigment content of millet was investigated by referring to the related research on sake of Japan.The results showed that appropriately increasing the milling degree of millet(DOM 15%)can significantly increase the proportion of starch in millet and improve the quality of millet as raw material for wine brewing,but at the same time will cause a large amount of loss of millet yellow pigment,which does not meet the research expectations.Therefore,this optimization method of millet raw material is not suitable for this study.(3)Research on the development and optimization of millet wine brewing technology according to the traditional rice wine brewing process.Based on the basic physical and chemical indexes and sensory evaluation results of millet wine,the optimal yeast,Angel highly active dry yeast,was selected as the fermentation strain.The optimal conditions for rice immersion were determined by single factor test: water addition proportion 150%,soaking temperature 20 ?,soaking time 36 h;koji addition proportion 0.6%,saccharifying temperature 30 ?,saccharifying time 60 h;yeast addition proportion 0.22%,fermentation temperature 32 ?,fermentation time 5 d,with 11.3%vol alcohol content.The corresponding indexes of each stage of millet wine brewed under the optimal technological conditions are basically consistent with the predicted results of response surface methodology,which provides a certain reference for obtaining high-quality millet rice wine and its industrial production.(4)The combination of HP-SPME and GC-MS was used for qualitative and quantitative analysis of volatile flavor components in different millet wine.A total of 222 flavor substances were detected in 5 varieties of millet rice wine,among which 56,92,98,81 and 74 kinds of flavor components were detected respectively in Gold 1,Xiaoxianggu,Dajinmiao,Jingu21 and Oriental Bright,with esters and alcohols as the main compound in millet wine.The flavor substances contained in different millet wine varied greatly,and only 5 flavor components were detected in all kinds of millet wine,which were ethyl octanoate,ethyl caproate,diethyl succinate,ethyl acetate and ethanol-a.Besides,the content of these flavor compounds varies in different millet wine.Except for ethyl caprylate,the contents of other components in different millet rice wine were significantly different.(5)Under the same fermentation conditions,the main physical and chemical indexes of millet wine brewed by different varieties millet are quite different.Among them,millet wine brewed by Xiaoxianggu has high alcohol content,reaching 12.73%vol,high yield of wine,and the highest sensory evaluation score.The content of millet yellow pigment in different millet wine is different,while the overall conversion rate was not high,with the highest content of Dongfangliang(51.73 ?g/L),followed by Jingu 21.At the same time,the content of the other three varieties was similar,between 32 and 36 ?g/L.There was a difference in EC content among millet wine brewed by different varieties,but the overall content was relatively high,among which the EC content of Jingu 21 was significantly higher than that of other varieties,reaching 269.88 ?g/L,and the EC content of Gold 1 was the lowest.Therefore,the comprehensive analysis shows that Xiaoxianggu is a superior millet rice wine product,which is produced with thorough fermentation,rich flavor components and relatively high millet yellow pigment content. |
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