LAB effective in formation of dairy flavor inducing δ-lactones from grapeseed oil.
Sub-lethal heat stress significantly improved the δ-lactone production by LAB.
Higher lactone yield was observed in early stationary phase.
Pre-fermentation step positively influence lactone generation.
Insight into the development and optimization of a novel fermentation for δ-lactones.
Agroscope Culture Collection was screened to identify bacterial strains effective in production of dairy flavor inducing lactones using grapeseed oil as a substrate. Lentilactobacillus parafarraginis FAM-1079, Lactococcus lactis subsp. lactis FAM-17918, and L. lactis subsp. lactis biovar diacetylactis FAM-22003 showed the most efficient formation of targeted δ-lactones. The application of sublethal heat stress significantly increased target lactone production. The most profound improvement was for L. lactis subsp. lactis biovar diacetylactis where δ-octadecalactone generation was improved by factor of 9. The pre-fermentation step as well as growth phase in which bacteria are harvested did not have a significant impact on lactones yield. The lactone production process from vegetable oil developed in this study offers a new way of developing a natural flavor ingredient for incorporation into plant-based products.