Title : Solid-state fermentation for Chinese liquor production
Abstract:
Chinese liquor (Baijiu) is the world’s largest consumed spirit (over 4 billion litres annually, total output values 40% of fermentation industry and 68% of brewing industry in China with Profit/Tax: $80 billion/$10.5 billion, 2016). Typically, with Jiuqu (as ort of Koji) as starter, Chinese liquor is fermented and distilled under solid-state conditions. The traditional manufacture process consists of an aerobic part (with Aspergillus) for starter and an anaerobic part (with Saccharomyces cerevisiae and Lactobacillus, etc.) for liquor. Despite a certain degree of stable production, the traditional manufacture process is artisanal and unpredictable, leading to quality defects even safety concerns. Better understanding and control of the solid-state fermentation process will help to get an optimized environment for liquor flavour formation, the ultimate criterion of liquor quality. First, we use a model system to simulate and study the basic principles under starter (aerobic) fermentation focusing on water change. Then for liquor (aerobic) fermentation, we use online and offline methods to detect key process parameters and modelling. The hidden knowledge behind the traditional Chinese liquor production is rich in useful principles including flavour chemistry, microbial growth, solidstate fermentation, enzyme production, bioconversion, microbial community evolution and metabolism, and process engineering. Therefore, to get insight into the hidden knowledge behind the complicated and somehow empirical solidstate fermentation process of Chinese liquor can enrich the food sector to improve our quality of life and benefit other industrial sectors in the modern biomass-based technology, economy and society. Here we used mathematical modelling to study dynamics under traditional solid-state fermentation using Chinese liquor production system as a model. This work can be used to define most important factors, guide the scale-up and process control of traditional solid-state fermentation.
