Microbial and flavor modulation of Jinhua ham at the fermentation stage by a synthetic mold and yeast community.

This study investigated the effect of individual inoculation with Penicillium (Penicillium aethiopicum & Penicillium chrysogenum, PP), yeast (Candida parapsilosis & Rhodotorula mucilaginosa, CM) and their co-inoculation (MI) on the microbial ecology and flavor of Jinhua ham. Inoculation established target fungal populations (>6.0 log CFU/g) successfully increased lipase activity (peak in MI) and inhibited lipid oxidation, peroxide values and Aspergillus community to <10% compared to the control. PP accelerated the release of free fatty acid, especially unsaturated fatty acids, driving total volatile aldehyde concentrations by 5.0-, 1.5-, and 2.2-fold in PP, CM, and MI, respectively, compared to the control. Consequently, hams in the PP group exhibited stronger green and meaty odor scores, lower off-odor scores, and enhanced W1S, W2S and W3S sensor responses. In contrast, CM and MI increased monounsaturated fatty acids, alcohols, aldehydes, carboxylic acids, esters and pyrazines contents with stronger mellow, green & meaty odor scores, as verified by robust W1W, W1S, W3S and W5S sensor responses than the control. These findings indicate that targeted Penicillium or yeast multi-species combination strategies promoted the formation of desirable aldehydes, ketones, esters and pyrazines contents and produced green, meaty and mellow flavor profile of Jinhua ham.