Abstract:In order to analyze the changes in volatile compound profiles of Pixian broad bean-chili paste (BCP) during koji making, moromi fermentation and post fermentation as well as to reveal the predominant volatile compounds in BCP and their origins, a systematic analysis of volatile compounds were carried out in BCP, its ingredients (broad bean cotyledon BBC, and fresh chili FCL) and semi-finished products (broad bean koji BKJ, pickled chili PCL, and broad bean moromi BMR). Through HS-SPME-GC-MS method, there were altogether 73 volatile compounds from all the studied samples(such as 6 hydrocarbons, 11 alcohols, 8 carbonyls, 8 heterocycles, 13 terpenoids, 18 esters, 6 acids, and 3 miscellaneous compounds). Total volatile contents of the ingredients were relatively low, showing (19.64±3.84) μg/g and (7.84±1.30) μg/g (an equivalent of 4-methyl-2- pentanol as an internal standard) in BBC and FCL, respectively. Many volatiles in BBC, FCL and BKJ were not found in BCP, indicating that their volatile profiles were not strongly related to those in the final products. Total volatile contents in broad bean moromi (BMR) and pickled chili (PCL) increased evidently to (82.42±17.63) μg/g and (49.71±8.06) μg/g after fermentation. Larger proportion of terpenoids and alcohols were found in PCL, indicating linalool, phenyl-ethanol, 2-methoxy-3- isobutyl pyrazine etc. as the key flavor compounds. More heterocyclic compounds, carbonyls and acids were detected in BMR, indicating phenylethanol, 1-octene-3-ol, phenylacetaldehyde etc. as the key flavor compounds. Total volatile contents in BCP were further increased (exceeded 100 μg/g) with esters as the most abundant compounds. Key flavor compounds of BCP included ethyl laurate, phenyl-ethanol, linalool etc. With the extension of post fermentation, changes in total volatile compounds, volatile composition and key flavor compounds in BCP were relatively low, indicating that they tended to be stable at this stage. Moreover, FCL was the main origin of terpenoids in BCP. Heterocyclic compounds and 4-ethyl-guaiacol were contributed mostly by BMR, while esters were formed in the post-fermentation stage.
