QDA and GC-IMS Analysis of Different Grades of Stir-fried Flavor Characteristics of Pixian Douban

Abstract:

The changes in the flavor characteristics of different grades of Pixian Douban after stir-frying were evaluated using a quantitative sensory descriptive method (QDA) and gas chromatography-ion mobility spectrometry (GC-IMS). The QDA analysis revealed that premium Douban possesses a low moisture content and a fruity, winey, malty, and burnt aroma after stir-frying. The higher water content of the first and second grade Douban led to greater differences in sensory scores compared with extra-grade Douban, but exerted less influence on the main sauce flavor. The GC-IMS detected 45 compounds, comprising 11 alcohols, 9 aldehydes, 8 esters, 6 ketones, 5 alkenes, 2 acids, 2 heptane, 1 pyridine, and 1 furan; however, many compounds remain unidentified. After stir-frying, the proportion of alcohols in the Douban increased from 14% to 37%, and the proportion of esters substantially increased from 2% to 11%. This indicates that stir-frying converts and concentrates the alcohols in the dal in a Maillard reaction. The resulting aroma is fruity, alcoholic, malty, and sour. High-temperature stir-frying results in the conversion of certain aldehydes into esters and ketones, altering the soy sauce flavor of the Douban to a burnt, fatty aroma. This study reveals the remarkable influence of the moisture content of different grades of Pixian bean paste on the flavor characteristics of stir-fried bean paste, providing crucial technical support and guidance for the advanced processing and innovative development of Douban.