Study On Brewing Technology Of Shanlan Rice Wine And Shanlan Rice Vinegar

Shanlan rice is a unique upland rice of Li nationality in Hainan Province.It contains iron,zinc and other trace elements suitable for human body absorption.In this study,Shanlan rice was used as raw material to make composite qiuqu suitable for the fermentation of Shanlan rice wine.Response surface experiment was used to optimize the brewing process of Shanlan rice wine.Meanwhile,pasteurization and intense pulsed light sterilization were carried out on Shanlan rice wine products to study the changes in physicochemical properties,free amino acids and flavor substances before and after sterilization.The change of physicochemical properties and flavor metabolites of Shanlan rice vinegar was studied by adding acetic acid bacteria to fermented Shanlan rice vinegar based on lees of filtered wine solution.The results are as follows:1.Rhizopus oryzae and Saccharomyces cerevisiae were selected to produce complex qiuqu.The effects of qiuqu cultivation ratio,bran proportion and water content on the saccharifying enzyme activity of qiuqu were analyzed by response surface experiment.When the water content was 73%,the bran proportion was 96%,and the add of qiuqu preparation was 3.5d,the activity of the saccharifying enzyme was 482.23± 3.45 U/g,which was close to the predicted value.2.Shanlan rice wine was brewed with compound qiuqu.The effects of fermentation time,qiuqu addition and water addition on the quality of Shanlan rice wine were analyzed by single factor experiment and response surface experiment.At the same time,sensory evaluation was used as the main index to optimize the experiment,and the optimal fermentation process of Shanlan rice wine was determined as: the fermentation temperature was 24.5 ℃,the content of koji was 0.78%,the content of water was 119%,and the sensory score was 79.6.3.The optimized conditions were pasteurized and intense pulsed light sterilized.The physicochemical properties,free amino acids and flavoring substances of Shanlan rice wine were compared before and after sterilization,and suitable sterilization conditions were selected.The experimental results showed that compared with the control group,the physicochemical properties of Shanlan rice wine treated by the two sterilization methods were slightly affected.The 60 s pulse treatment reduced the content of bitter amino acids.It maintained the content of sweet amino acids and umami amino acids,so as to balance the taste of Shanlan rice wine.After pasteurization,the content of the ester substance in wine was reduced by 90%,and the content of the alcohol substance was reduced to different degrees.Intense pulsed light sterilization had little effect on the content of esters and increased the content of alcohols.Further analysis of the main flavor metabolites showed that 60 s pulse treatment enhanced the important flavor substances of Shanlan rice wine,which was suitable for sterilization conditions of this wine.4.The physical and chemical indexes of Shanlan rice vinegar were analyzed by adding acetic acid bacteria to fermented Shanlan rice vinegar.The free amino acids,organic acids and flavor metabolites in the fermentation process of Shanlan rice vinegar were determined by high-performance liquid chromatography and headspace solid-phase microextraction,and the changes in the fermentation process were analyzed.The results showed that the physicochemical properties of the vinegar changed greatly during fermentation.The total acid content increased gradually during fermentation,while the p H value showed a slow decline.The contents of lactic acid and acetic acid were higher in the fermentation process of Shanlan rice vinegar.The total content of free amino acids was higher in the middle stage of fermentation,and the flavor mechanism of finished rice vinegar was mainly sweet amino acids.By analyzing the relative contents of differential metabolites,it was found that with the extension of fermentation time,the relative contents of most of the differential metabolites increased significantly.According to the analysis of metabolic pathways of differential metabolites,17 key metabolic pathways were selected,and the enrichment degree of microbial metabolic pathways in different environments was the most significant.