Effect Of Exogenous Amino Acids On The Fermentation In Chinese Rice Wine

The content of amino acids in Chinese rice wine is not only the important nutrients and flavor substances, but also the precursors of higher alcohols, biogenic amines and some volatile aroma components. In the process of Chinese rice wine brewing, the protein in the raw glutinous rice was degraded by microbial enzymes, which were converted into free amino acids mostly. The small amounts of the amino acids were converted into higher alcohols and biogenic amines. In the fermentation of Chinese rice wine, the relationship between the proteins of raw material and amino acids or their metabolites is not clear. The changes of amino acid composition in the fermentation process of Chinese rice wine were studied in this paper.(1) A reversed-phase high performance liquid chromatogrphic(RP-HPLC) method has been presented for the simultaneous determination of 17 free amino acids and 7biogenic amines in Chinese rice wine. Samples were pre-column derivatised with phenylisothiocyanate(PITC), separated using Inertsil ODS-SP C18 chromatography column(250mm×4.6mm, 5μm), eluted with a mobile phase composed of sodium acetate,acetonitrile and ultra-pure water, and detected at 254 nm wavelength..The calibration curves of 17 amino acids and 7 bogenic amines all exhibited good linearity over the range from 2.0 to 500mg/L and 0.5 to 125mg/L.Mean recoveries for amino acids and biogenic amines were between 86.44% and 99.75%, and the RSD were 0.31%~3.53%. the limit of detection for 17 free amino acids and 7 biogenic amines is 0.02~0.25mg/L, and the limit of quantification is 0.25~4.50mg/L. The method is sensitive, accurate, and reliable for the determination of amino acids and biogenic amines in Chinese rice wine.(2) The free amino acids, biogenic amines and aroma components in different fermentation stages of Chinese rice wine were identified using high performance liquid chromatography(HPLC) and the gas phase mass spectrometry(GC/MS). The results showed that with the fermentation process of Chinese rice wine, the free amino acid composition, histamine and tyramine component continue to increase, but tryptamine,phenylethylamine, putrescine, cadaverine components will continue to reduce; The fermentation conditions had significant effects on the species composition and content of aroma components. Alcohol aroma components are generated are mainly produced during the period of pre fermentation and during the fermentation period. Ester aroma components are mainly produced in the post fermentation period.(3) The effect of the adding arginine and glutamic acid on the fermentation of Chinese rice wine was studied. The results showed that the treatment of addition arginine lead toalcohol production decreased 12.41%, while the total amount of biogenic amines increased by 15.82%. Adding glutamate treatment had no significant effect on alcohol production;while the content of biogenic amines reduced of 4.57%.(4) The effect of glutamic acid addition and adding time on the fermentation of rice wine was studied. The results showed that with the increase of the added amount of glutamic acid, The content of ethyl acetate have increasing, reaching the highest content when glutamate was added to 400mg/L. And when glutamate was added 800mg/L, the content of urea decreased by 38.65%.