Ratio limitation of burnt-bitter-aroma compounds in strong-aroma Baijiu

Burnt-bitter-aroma (BBA), an off-odor reminiscent of burnt grains, is associated with aroma deterioration in strong-aroma Baijiu. The key burnt-bitter-aroma compounds (BBAC) and their limitations relative to ethyl hexanoate remain unclear. GC-MS and HPLC quantified 89 compounds in normal and burnt-bitter-aroma Baijiu. OPLS-DA identified 13 VIP > 1 compounds, among which furfuryl alcohol, 1-butanol, 1-hexanol were unpleasant and more abundant in normal Baijiu but exhibit lower ratios relative to ethyl hexanoate. Therefore, an innovative BBAC analysis method was developed by calculating pairwise compound ratios, correlating them with BBA scores, followed by logical deduction and flavor analysis, which selected twenty candidate compounds. After recombination and omission experiments, seven key contributors including furfuryl alcohol, 1-butanol, 2-butanol, 1-hexanol, 2,4-di-tert-butylphenol, p-cresol and ethyl furfuryl ether were confirmed. Their recommended ratios to ethyl hexanoate were below 0.2862, 0.1559, 0.0443, 0.0943, 0, 0.000084, and 0.0018, respectively. This study provides a theoretical basis for off-odor control through blending.