Bacterial-driven lipid remodeling in avocado fermentation via hydroxylation and oxidation routes

We investigated the lipid metabolism of three lactic acid bacteria in fermenting two avocado cultivars. Using Liquid Chromatography-High-Resolution Mass Spectrometry, we tracked the fermentation-induced modifications in native lipid profiles. These modifications unveiled an increase in free fatty acids (FA) but also the generation of their oxidized derivatives associated with 14 different m/z ratios. Mono-, di-, and tri-hydroxylated derivatives originating from major unsaturated FA (18:1, 18:2, 18:3), along with oxidized forms of 16:0 and 18:0 FA, were recognized through the interpretation of tandem mass spectrometry data. Tandem mass spectrometry also suggested oxidized derivatives from minor FA (16,1, 16:2). In certain cases, bacterial-driven hydroxylation processes were confirmed on oleic acid in synthetic media. Overall, bacterial-driven hydroxylation and oxidation enriched avocado with potentially bioactive lipids, offering opportunities for nutraceutical and food applications, with minimal undesirable sensory effects specifically affected by microbial species and avocado cultivar.