浓香型白酒发酵过程中高级醇与游离氨基酸合成规律OA

Using 20-year-old fermentation pits(JC20)and 40-year-old fermentation pits(JC40)as the research objects,the contents of higher alcohols(isobutanol and isopentanol)and 17 common free amino acids in different layers of Zaopei in these samples were determined using gas chromatography-mass spectrometry and high performance liquid chromatography.The correlation was calculated based on the Pearson method.The results showed that the main synthesis periods of isobutanol and isopentanol in the Zaopei was in the early stage of fermentation,and the contents of isobutanol and isopentanol in the Zaopei of JC40 were lower than those in JC20.At the end of fermentation,the content of isopentanol was higher than isobutanol,with the maximum concentrations of 46.42 and 14.98 mg/kg,respectively.The determination results of free amino acids indicated that 16 amino acids increased gradually during the fermentation,and the content of arginine decreased in the middle layer of JC20 and the middle and lower layers of JC40.The correlation analysis results showed that proline and lysine in each layer of Zaopei from JC20 had a highly significant positive positive correlation with isobutanol(P≤0.01),and alanine,cysteine,glycine,leucine,and proline had highly significant positive correlation with isopentanol(P≤0.01).The types of amino acids that significantly correlated were much higher in JC20 than those in JC40.However,in JC40 pit mud,there was a highly significantly positive correlation between proline and isobutanol in each layer of Zaopei(P≤0.01).It was concluded that during the fermentation process of strong-flavor(Nongxiangxing)Baijiu,the higher alcohols were mainly synthesized through sugar metabolism in the early stage,and free amino acids were produced in large quantities with the fermentation,and gradually turned to amino acid metabolism.