Exploring the effects of Lactobacillus acidophilus GIM1.208 on browning and flavor quality of Paojiao based on nontargeted metabolomics and GC-MS

This study utilized nontargeted metabolomics in combination with GC-MS technology to investigate the impact of Lactobacillus acidophilus GIM1.208 (LA) fermentation on the browning and flavor quality of Paojiao. The findings revealed that LA not only suppressed the activity of key browning enzymes (Peroxidase, Polyphenol oxidase, Phenylalamine ammonia lyase) and the accumulation of malondialdehyde (MDA) but also decreased the consumption rate of crucial substances involved in the browning process, such as phenols and ascorbic acid. A total of 1004 metabolites were identified in naturally fermented Paojiao (CK) and LA-fermented Paojiao (AF), with 64 differential metabolites, mainly comprising amino acids and fatty acids. The differential metabolites enrichment primarily occurred in four main metabolic pathways: arachidonic acid metabolism, pyrimidine metabolism, biosynthesis of valine, leucine, and isoleucine, and phenylpropane biosynthesis. Overall, 179 flavor compounds were detected in CK and AF, including 43 differential volatile flavor compounds. AF exhibited a more diverse range of volatile flavor compounds (140) compared to CK (118), particularly esters and alcohols, contributing to a richer flavor profile in AF's Paojiao. In summary, LA effectively inhibited the browning process of Paojiao and enhanced its flavor quality, offering valuable reference for quality control and flavor research of Paojiao products. •Fermentation of Paojiao by Lactobacillus acidophilus GIM1.208 can improve its color.•Non targeted metabolomics was used to evaluate the metabolites in Paojiao.•Fermentation of Paojiao by Lactobacillus acidophilus GIM1.208 can improve its flavor.•This provided experimental basis for the development of biological browning control.•Esters are the main volatile flavor compounds in Paojiao.