Study On The Brewing Technology Of Coix Seed And Pueraria Lobata Chinese Rice Wine

This paper aims at screening out the strain with saccharification function from mold strains, which is suitable for brewing chinese rice wine. Then using the strain to make pure breed fermentation for making liquid qu as zymin for producing chinese wine. The liquid fermentation conditions of coix seed and pueraria lobata chinese rice wine were studied and analyzed. The parameters of fermentation process were optimized. GC and GC-MS were applied to analyze characteristic components and flavor substances in order to compare the differences in styles and qualities between these two types of chinese wine: one made by fermentations of traditional wine cube and wheat koji, the other made by pure liquid fermentation methods.Which is in order to improve the technological conditions of producting chinese rice wine by liquid fermentation and enhancing the taste quality of the chinese rice wine.Twelve strains were isolated from chinese rice wine distiller’s yeast and malt. Then eight strains were selected preliminarily by Transparent circle screening method,and through determined the liquefaction power,saccharifying power and protease activity of the bran koji that was made by the eight strains pure cultivation,a strain M-16 with excellent saccharification function was finally screened out.The experimental results revealed that the liquefaction power of M-16 was 192.0U/g,the saccharifying power reached 3102.6U/g,the protease activity reached 1072.2U/g. After making observation of the physiological and biochemical of the strains,It was initially identified as Mould.The strain M-16 belongs to Aspergillus after 18 S fungal identification by Sangson Biotech(Shanghai)Co.,Ltd.The experiments showed that the strain can be suitable as saccharifying strains for producing chinese rice wine.Firstly, the liquid fermentation to produce saccharifying enzyme medium of saccharifying strains, M-16 was studied by single factor experiment. The optimized carbon source, organic nitrogen source, inorganic nitrogen source, mineral salt were corn flour, mora meal,(NH4)2HPO4 and CaCO3 respectively. Orthogonal optimization results showed that optimum compositions were 5% corn steep liquor, 4% corn flour, 1%(NH4)2HPO4, 7% bran. The highest enzymatic activity reached to 3237.32U/mL. Secondly, the culture conditions of liquid saccharifying enzyme of M-16 were studied. The orthogonal tests with four factors and three levels were applied to optimize the culture conditions of saccharifying enzyme. The results showed that the optimized conditions were as follows: fermentation time was 6d, inoculum age was 24 h, loaded liquid was 30 m L/250 m L, inoculation quantity was 10%, temperature was 30℃, initial pH was 5. The highest activity reached to 5666.32U/m L.The raw material ratio(coix seed/pueraria lobata/ sticky rice), ratio of water to material, additive amount of the strain M-16 liquid qu, pre-fermentation temperature and time, post-fermentation temperature and time of the fermentation process of coix seed and pueraria lobata chinese rice wine were studied by single factor experiment. The variance analysis results showed that ratio of water to material, additive amount of yeast, pre-fermentation temperature and time influenced sensory quality of coix seed and pueraria lobata chinese rice wine obviously. Moreover, these four factors were studied by L9(34) orthogonal tests. The tests demonstrated that the best zymotechnique was as follows: ratio of water to material was 2.5, additive amount of yeast was 0.15%, pre-fermentation temperature and time were 29℃and 7d respectively. The ratio of water to material, pre-fermentation temperature and time, additive amount of yeast in sequence had important influence. Under the optimal fermentation conditions, coix seed and pueraria lobata chinese rice wine presents orange yellow with amber, transparent and shiny, mellow rich with slight fragrance of Pueraria lobata, which tastes mellow, soft and refreshing. It has coordinating components with unique style of coix seed and pueraria lobata chinese rice wine.Finally,GC/MS was applied to analyze flavor substances of coix seed and pueraria lobata chinese rice wine by traditional fermentation and pure breed fermentation. 45 flavor substances were detected, which mainly contained alcohols, esters, aldehydes, hydrocarbons, alkenes, furans and pyrazines. 32 flavor substances were detected in traditional fermented chinese rice wine, 41 flavor substances were detected in pure breed fermented chinese rice wine. Ethyl acetate, isobutanol, 3-methyl-1-butanol, acetic acid- 3-methylbutyl ester, phenethyl alcohol(relative amount>2%) were both detected in the two samples. Gas chromatography showed that there were 13 microconstituents both in pure liquid fermented chinese rice wine and traditional chinese rice wine, of which 13 in the former and 11 in latter. What’ s more, two unknown compounds were found in both samples. Valeric acid and acetic acid were found in pure liquid fermented chinese wine but not in traditional chinese rice wine. Of higher alcohols, isobutanol, n-butyl alcohol, isoamyl alcohol, β-phenethyl alcohol were all detected in both samples. In summary, there are more higher alcohols in traditional fermented chinese wine than those in pure fermented chinese rice wine.