Research Progress on the Profile of Trace Components in Baijiu

Baijiu is a traditional solid-state distilled liquor prepared from grain fermentation of China, with a more than 2,000 years of history. As the national liquor of China, Baijiu occupies an important position in China's food industry. In 2018, the total sales revenue of Baijiu industry reached 536.383 billion yuan and total annual profit was 147.645 billion yuan. Because of the complex raw materials, special technology and co-fermentation of multiple strains, the composition of Baijiu is complex. Of note, although the trace components only account for 2% of Baijiu, they contribute to the flavor and functional quality of Baijiu. As reported, these trace components mainly include alcohols, aldehydes, ketones, esters, acids, carbonyl compounds, nitrogen compounds, sulfur compounds, short peptides etc. Among them, volatiles play an important role on aroma profile and functional quality of Baijiu, while non-volatiles are the precursor of volatiles and the contents of them will influence the contents of volatiles in Baijiu, thereby affecting the flavor and functional quality of Baijiu as well. This perspective mainly introduces the technological process of Baijiu production, summarizes recent progress in the research on the trace components in Baijiu, especially for the influence of trace components on the flavor and functional quality of Baijiu.