Abstract: In this research, we aimed to investigate the differences in physicochemical properties including total acid, amino acid nitrogen, reducing sugar, moisture content, color value and pungency degree as well as volatile flavor composition among Pixian broad-bean pastes prepared with ‘Erjingtiao hot peppers from different growing areas in China during fermentation. Solid phase micro-extraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS) and an electronic nose (EN) were used to evaluate the volatile components and discriminate flavor characteristics among Pixian broad-bean pastes. The results showed that Pixian broad-bean paste made with hot peppers from Bijie had the highest total acid content and color value. In contrast, the lowest values of the two indicators were observed in Pixian broad-bean paste made with hot peppers from Chaotian. In addition, Pixian broad-bean paste made with hot peppers from Luzhou contained the highest reducing sugar and moisture content, but lowest amino nitrogen content. Pixian broad-bean paste made with hot peppers from Jianyang had the highest amino nitrogen content and pungency degree. Pixian broad-bean paste made with hot peppers from Zitong had the lowest levels of pungency degree, reducing sugar and moisture content. A total of 176 volatile compounds were identified in the five samples, 41 of which were common to these samples. Aldehydes were the main volatile compounds found in Pixian broad-bean pastes made with hot peppers from Bijie and Luzhou, while esters were predominant in the remaining three samples. In principal component analysis (PCA) and linear discriminant analysis (LDA), the cumulative contribution of the first 2 principal components accounted for 99.81% and 99.35% of the total variance, respectively, suggesting that the sensors had high recognition performance and allowed excellent discrimination among the samples. These findings support the combined use of SPME-GC-MS and electronic nose to evaluate and discriminate flavor characteristics among Pixian broad-bean pastes prepared with hot peppers from different geographical origins, providing a guidance for the development of Pixian broad-bean paste products that can meet different demands.

Key words: hot pepper, Pixian broad-bean paste, solid phase micro-extraction combined with gas chromatography-mass spectrometry, electronic nose, volatile components