Sensory-Guided Characterization of Key Aroma Compounds in Five Five-Grain Strong-Flavor Baijiu Samples

Abstract

Five-grain strong-flavor Baijiu is characterized by its intense pit aroma and mellow, sweet, and clean taste, and it plays a pivotal role in the Chinese Baijiu market. Its production is based on key processes including solid-state fermentation in mud pits, continuous fermented grain supplementation, mixed steaming and distillation, and the use of medium- to high-temperature Daqu. In terms of aroma composition, ethyl hexanoate is the predominant compound and, together with ethyl lactate, ethyl acetate, ethyl butyrate, and other esters, forms a well-balanced and complex flavor system. In this study, the five-grain strong-flavor Baijiu samples were produced using sorghum as the primary raw material, supplemented with rice, glutinous rice, wheat, and corn through multigrain co-fermentation. Different sorghum varieties can influence microbial metabolism and flavor formation due to variations in physicochemical properties such as starch, protein, and tannin content. Therefore, a sensomics-based approach was employed in this study. Under the guidance of national-level Baijiu experts, an olfactory panel was selected and systematically trained. By integrating quantitative descriptive analysis (QDA), gas chromatography–olfactometry–mass spectrometry (GC-O-MS), and aroma extract dilution analysis (AEDA), the aroma profiles and key aroma compounds of five-grain strong-flavor Baijiu produced from five different sorghum varieties were comprehensively characterized.