Abstract:In this study, yellow water, a by-product of Luzhou-flavor liquor, was used as the research material to investigate the influence of processing conditions including the amount of edible alcohol (95%, V/V) for addition, reaction temperature and the amount of Candida antarctica Lipase B (CALB) on the esterification of yellow water. The product refining process was also discussed. The results of single factor experiment and response surface optimization showed that the increases in ester content and aroma were the greatest under the optimum conditions (amount of edible alcohol, 52.5% (V/V); amount of CALB enzyme, 5.32% (W/V); 31.5 ℃ for 48 h), with the contents of ethyl acetate, ethyl lactate, ethyl hexanoate and total ester being 1.81 g/L, 6.09 g/L, 14.49 g/L and 22.39 g/L, respectively, and the concentration of liquor flavor increased by 31.9 times. The conversion rate of the CALB enzyme remained unchanged after it was used repeatedly (10 times). A mixture of liquor aroma-active substances were obtained after distillation and extraction of the esterification reaction product of yellow water, with the total ester recovery rate being 76.56%. This study has shown that yellow water can be used to produce functional esterification liquids such as natural equivalent flavors and liquor-blending liquid. The optimized process required mild conditions and a short reaction cycle and is industrial scalable, leading to a significantly increased ester content. This study is of great significance for the recycling of liquor yellow water resources.
