Triacylglycerols hydrolysis and hydroxy- and epoxy-fatty acids release during lactic fermentation of plant matrices: An extensive study showing inter- and intra-species capabilities of lactic acid bacteria

This study aims to show that lactic fermentation by selected starters can enrich plant matrices with hydroxy- and oxo-fatty acids. The behavior of 31 lactic acid bacteria strains was investigated during the fermentation of Persian walnut, which was selected as a model growth substrate due to its inherent lipids content. The content of the following free fatty acids increased in the majority of the fermented walnut samples: linoleic, alpha-linolenic, palmitic, and oleic acids. The increase of diacylglycerols and, especially, monoacylglycerols levels in fermented walnuts confirmed that strain-specific bacterial lipolytic activities hydrolyzed triacylglycerols during walnut fermentation. Twelve hydroxylated or epoxidized derivatives arising from oleic, linoleic, and linolenic fatty acids, in five groups of isomeric compounds, were also identified. In addition to the better-known lactobacilli, certain strains of Weissella cibaria, Leuconostoc mesenteroides, and Enterococcus faecalis emerged for their lipolytic activities and ability to release hydroxy- and epoxy-fatty acids during walnut fermentation.

Automated summary

This study demonstrates that lactic fermentation using selected starters can increase the presence of hydroxy- and oxo-fatty acids in plant matrices. The behavior of 31 strains of lactic acid bacteria during the fermentation of Persian walnuts was investigated, with a focus on the increase of certain fatty acids and the release of hydroxy- and epoxy-fatty acids. The study identified various bacteria strains, including Weissella cibaria, Leuconostoc mesenteroides, and Enterococcus faecalis, with notable lipolytic activities and the ability to produce hydroxy- and epoxy-fatty acids during walnut fermentation.