基于理化、酶活力和不挥发化合物解析不同等级高温大曲异质性OA

The quality of high-temperature Daqu significantly impacts the yield and quality of Jiangxiangxing Baijiu.This study char-acterized the heterogeneity of high-temperature Daqu at different grades using physicochemical indicators,enzymatic activity analysis,and derivatization-GC-MS technology to detect non-volatile compounds.Results indicated that the premium-grade Daqu exhibited significantly higher acidity,protease activity,and amino acid nitrogen content than the normal-grade Daqu.Conversely,the normal grade Daqu had higher moisture,starch content,protein content,and saccharification enzyme activity.105 non-volatile compounds were identified by qual-itative and quantitative analysis.The total non-volatile compound content was highest in the premium-grade Daqu,primarily consisting of amino acids(19％-28％),sugars(25％-41％),and sugar alcohols(20％).Amino acid content increased with Daqu quality,while sugar content decreased.Seventeen key non-volatile compounds(variable importance in the projection＞1,|log2fold change|≥1,P＜0.05)were identified by partial least squares-discriminant analysis(PLS-DA).The premium-grade Daqu was enriched in 11 key com-pounds,including pyroglutamic acid and mannitol,whereas the normal-grade Daqu showed significant accumulation of ribitol,xylose,glucose,glutamic acid,and lactic acid.These results provide a theoretical basis for analyzing quality differences between high-temperature Daqu of different grades and offer insights for controlling and enhancing quality.