Research Of γ-of Aminobutyricacid In Guangdong Hakka Rice Wine

Guangdong hakka rice wine is a kind of nutritional health wine with low alcohol, whichcontain a variety of nutrients and functional ingredients. The gamma-aminobutyric acid(GABA) of hakka rice wine has anti-anxiety, fall blood pressure, strengthen memory, improvebrain function, lose weight and improve the function of liver, kidney and other physiologicalactivity, the research on GABA of hakka rice wine with great significance. This researchmainly on microbes and their ability to produce GABA, including GABA hakka rice wineprocess optimization and GABA and its related substances in hakka rice wine fermentation,explores the dynamic change, the research results were as follow:(1) Red kojic rice, wheat koji and Chinese yeast are as starter culture of guangdonghakka rice wine, and microorganisms were separated from those starters.2strains wereisolated from red koji, including monascus and yeast;7strains were isolated from wheat koji,including1strain of rhizopus,1strain of mucor,4strains of aspergillus and1strain of yeast;6strains were isolated from Chinese yeast, including1strains of rhizopus,4strains ofaspergillus and1strain of yeast. Those microorganisms were fermented by2%of glutinousrice medium, and the content of GABA in the fermented liquid were determined, and toexplored the microbial ability to produce GABA. Found that thoese microorganisms separatedfrom the red koji, wheat koji and Chinese yeast had capacity to produce GABA, differentmicrobial ability of GABA produce was different, rhizopus, mucor and several strains ofaspergillus fermented liquid of GABA content was higher, to more than40mg/L.(2)2k factorial experimental was used to optimized production of GABA hakkaprocess, six factors were selected to the optimization experiment, The results showed thatsoak rice time and bottling volume were significant influence on GABA content in wine;through the CCD response surface experiment to optimization those two factor, the modelequation was obtained: y=355.52979-0.10208*E-0.001*E2-0.013774*F2(y standed forGABA content, E standed for soak rice time, F standed for bottling volume), the optimumparameter of hakka rice wine making was Chinese yeast0.5%, wheat koji0.5%, red kojic rice5%, water content5%, bottling volume200g/L and soak rice time30h, and the hakka ricewine with295.79mg/L GABA, the taste and flavor of hakka rice wine was cahived superior standard.(3) In the earlier stage of primary fermentation and secondary fermentation of hakkarice wine making, the content of GABA was stable, later stage the GABA content wassignificant increased maintained at230mg/L and300mg/L; the key enzyme of GABAsynthesis is glutamic acid decarboxylase (GAD), in the early and later stage of fermentationthe GAD enzyme activity showed obvious rising trend, rice wine was added in thefermentation could lower the activity of GAD enzyme; due to the effect of alcohol after24days, GAD enzyme activity decreased gradually. Correlation analysised GABA and aminoacid, found that GABA had significant correlation with aspartic acid, glutamic acid, serine,histidine, alanine, isoleucine and lysine, extremely significant with glycine and methionine.Multivariate linear regression analysised GABA with amino acids, the result showed thefollowing relationship: y=-19.041+5.672X1+0.564X2-0.262X3+0.284X4(y standed forGABA, X1-X4respectively standed for alanine, tyrosine, valine and benzene acid content), theadjusted R2was0.990; Multivariate linear regression analysised GABA with total sugar, totalacid and amino acid nitrogen, the result showed the following relationship: y=-15.932+709.659X1-142.166X2+0.473X3(y standed for GABA, X1standed for amino acid nitrogencontent, X2standed for total acid content, X3standed for total sugar content), the adjusted R2was0.646.