LAUSR

Soaking is an important process in Chinese rice wine brewing. In this study, the influence of vacuum soaking on Chinese rice wine production was investigated. Rice subjected to a 1-h vacuum soaking process or a traditional 2-days soaking process was steamed and fermented. Our results showed that vacuum soaking led to similar absorbed water but less leached solids compared with traditional soaking and showed limited influence on the physiochemical characteristics of steamed rice. Monitoring of the fermentation process suggested that the content of amino acid nitrogen in the vacuum-soaked group was significantly higher than that of the traditional-soaked group, while the other indexes were similar. The detection of flavor substances in the rice wine indicated that the contents of organic acids and free amino acids were higher in the vacuum-soaked group, and the main kinds of volatile flavor compounds from the two groups were similar. Additionally, sensory evaluation reflected that the rice wine brewed with rice subjected to either of the two different soaking treatments had similar sensory performances. Our research indicated that vacuum soaking could effectively shorten the soaking time of rice in Chinese rice wine production, thus shortening the brewing cycle without sacrificing the quality of the rice wine.