Deciphering flavor profile and metabolic pathways in black chokeberry co-fermented by Lactiplantibacillus plantarum and Hansenula sp. via integrated volatilomics and metabolomics.

Aronia melanocarpa, renowned as the "king of anthocyanins", exhibits pronounced acidity, astringency, and amygdalin-derived bitterness in its berries, severely restricting its food applications. Currently, fermentation of A. melanocarpa is limited by a lack of suitable lactic acid bacteria (LABs), resulting in insufficient aroma and not delicious taste in the fermentation products. To address these, we isolated 139 LABs from fermented vegetables and screened three optimal strains of L. plantarum through acclimatization in Aronia juice and sensory evaluation. Using HS-SPME-GC-MS and GC-IMS, 143 volatile organic compounds (VOCs) were detected, among which 51 key aroma-active compounds with odor activity values (OAVs) >1 were identified. Thirty differential VOCs were screened via OPLS-DA with variable importance in projection (VIP) >1. Ten characteristic key aroma-active compounds were confirmed with the random forest algorithm. 1-butanol-3-methyl acetate, which has a fruity and sweet flavor, was a prominent marker aroma produced during fermentation. Fermentate 8-2 had the highest scores in sweet, sour, fruity, rose, whiskey and fatty. 244 non-volatile metabolites were detected by UHPLC-Q-TOF/MS, of which 50 differential metabolites were identified as markers to distinguish variations of black chokeberry fermentates. Pathway enrichment analyses revealed that phenylalanine, tyrosine, and tryptophan biosynthesis and linoleic acid metabolism, play pivotal roles in regulating volatile flavor compound formation. Syringin was first identified in black chokeberry and its LAB-fermented juices. Fermentation greatly improved the flavor and taste of the chokeberry juice. These findings provide critical theoretical support and practical guidance for the commercial production and processing of aronia and its fermentates.