Effects of sorghum nutritional quality on the brewing quality of strong-flavor Baijiu

Using 8 different varieties of sorghum (numbered as JZG, JZ12, CZ5, JZB, LZ1, JZ218, JZ109, LZ2) as the research objects, their physicochemical indexes were detected, and their effects on the physicochemical indexes of fermented grains of strong-flavor (Nongxiangxing) Baijiu and the volatile flavor components of the Baijiu were investigated. Based on the detection results, partial least squares-discriminant analysis (PLS-DA) and correlation analysis were carried out. The results showed that the moisture of different varieties of sorghum had little difference, while the contents of tannin, amylopectin, crude protein and crude fat had great differences. There were certain differences in the acidity, moisture, starch content and alcohol content of the fermented grains for Baijiu brewed from different varieties of sorghum. A total of 38 volatile flavor components were detected in strong-flavor Baijiu brewed from different varieties of sorghum, including 12 esters, 12 alcohols, 10 acids, and 4 aldehydes. The contents of ester substances were the highest (1 636.75-5 677.69 mg/L). According to variable importance in the projection (VIP) value and odor activity value (OAV), 14 different volatile flavor components (VIP value≥1) such as ethyl caproate and acetal, and 23 key volatile flavor components (OAV>1), such as ethyl acetate and isoamyl acetate, were screened. Correlation analysis showed that the amylopectin in sorghum was beneficial to alcohol production, and the contents of crude fat and tannin in sorghum were negatively correlated with the contents of main volatile flavor substances such as ethyl butyrate, ethyl caproate and caproic acid.