Characterization of flavor profiles and microbial communities in Ciba chili fermentation using metagenomics, untargeted metabolomics, and flavoromics

Abstract

Ciba chili are a distinctive chili condiment from southwestern China, those produced using single rehydration methods encounter challenges related to monotonous flavor and inconsistent quality. This study investigated the quality changes in Ciba chili over 0–28 days of natural fermentation. The physicochemical analysis revealed a significant decrease in pH, while total acidity and amino nitrogen content increased markedly. This indicates that fermentation effectively promoted acidification and increased the production of nitrogen compounds. Through untargeted metabolomics, 2106 metabolites were identified and annotated. KEGG pathway analysis of the differential metabolites revealed that 2-oxoglutarate, a key intermediate in the tricarboxylic acid (TCA) cycle, serves as a crucial metabolic hub for the synthesis of flavor compounds. Moreover, gas chromatography-ion mobility spectrometry identified 52 Volatile organic compounds (VOCs), with substantial increases observed in alcohols, ketones, alkanes, pyrazines, and furans following fermentation, all contributing to the enhanced aroma of Ciba chili. Dominant microbial genera, including Lactiplantibacillus, Weissella, and Leuconostoc, were strongly associated with VOCs and metabolites, playing a pivotal role in flavor development. The results suggest that fermentation is an effective method for improving the quality and flavor of Ciba chili, demonstrating substantial potential for practical applications.