Relation of ethanol δ¹³C, hexanoic acid δ¹³C and ethyl hexanoate δ¹³C in Baijiu

To explore the correlation among the stable carbon isotope ratio (δ¹³C) of ethanol, hexanoic acid δ¹³C and ethyl hexanoate δ¹³C in Baijiu with hexanoic acid and ethyl hexanoate as the main flavor components, based on the dynamic equilibrium reaction: ethanol+hexanoic acid $\rightleftharpoons$ethyl hexanoate+water in Baijiu, the correlations among ethanol δ¹³C, hexanoic acid δ¹³C and ethyl hexanoate δ¹³C in both Baijiu simulants and actual Baijiu samples were examined. The results showed that there was a multivariate linear relationship among the three components in the Baijiu simulants, and the linear relationship formula (1) was: ethyl hexanoate δ¹³C=ethanol δ¹³C×0.260+hexanoic acid δ¹³C×0.700-0.755, but it was not suitable for analyzing the correlation of the three components in Baijiu. There also existed a multiple linear relationship in the three components in Baijiu, the linear relationship formula (2) was: ethyl hexanoate δ¹³C=ethanol δ¹³C×0.109+hexanoic acid δ¹³C×0.205-15.658. Compared with formula (1), this formula had a smaller standard deviation and could better demonstrate the relationship among ethanol δ¹³C, hexanoic acid δ¹³C and ethyl hexanoate δ¹³C in Baijiu. It had certain applicability in Baijiu, providing technical support for the application of stable isotope technology in the exogenous addition of Baijiu.