白酒贮存过程中主要成分间氢键相互作用的量子化学计算

Quantum Chemistry Calculation of Hydrogen Bond Interactions between Major Compounds in Baijiu during Storage

用量子化学的方法研究乙醇-水、乙醇-风味成分、水-风味成分以及乙醇-水-风味成分之间的氢键相互作用,以期更深入地认识白酒的老熟机理。用密度泛函理论计算结果表明:在乙醇、水、风味成分的二元复合物和三元复合物中,结构稳定性由高到低的排序分别为乙醇/水-酸>乙醇/水-醇>乙醇/水-酯,以及乙醇-水-酸>乙醇-水-醇>乙醇-水-酯。酸类物质的羰基氧原子和羟基氢原子能分别与乙醇、水的羟基氢原子和氧原子生成氢键,使乙醇/水-酸和乙醇-水-酸复合物形成环状结构,故结构稳定性高。这应该是白酒在贮存过程中风味成分的质量浓度呈现"酸增酯减"的原因之一,同时也是贮存可以增强酒体中氢键相互作用、减少游离分子的原因。

In this work,the hydrogen bond interactions between ethanol and water,between ethanol and flavor compounds,between water and flavor compounds,and among ethanol,water and flavor compounds were investigated by quantum chemistry calculation to provide insights into the mechanism of Baijiu aging.The results density functional theory showed that the structural stability of the binary and ternary complexes was in the decreasing order of ethanol/water-acid>ethanol/water-alcohol>ethanol/water-ester,and ethanol-water-acid>ethanol-water-alcohol>ethanol-water-ester,respectively.The carbonyl oxygen atom and hydroxyl hydrogen atom in the organic acids could form hydrogen bonds with the hydrogen atom and oxygen atom in the hydroxyl group of ethanol or water,separately,causing the ethanol/water-acid and ethanol-wateracid complexes to form ring structures and consequently improving the structural stability.This may partially explain why the flavor components of Baijiu showed an increase in acids and a decrease in esters during storage and may also explain why storage could strengthen the hydrogen bond interactions and reduce free molecules in Baijiu.