Effect of Lactobacillus plantarum on olive and olive oil quality during fermentation process

The olive fruits were fermented with Lactobacillus plantarum ATCC 8014 and then some physicochemical properties of the extracted oil including chemical indices, fatty acid composition, functional groups, total phenol content, antioxidant activity and thermal properties were investigated. Some fruit quality indices such as color and texture also were determined. Results showed the concentration of unsaturated free fatty acids in treated samples increased after the fermentation process. The results of 2,2-diphenyl-1-picrylhydrozyl (DPPH) test demonstrated that L. plantarum can improve antiradicalactivity of olive oil. According to Pearson's test, phenolic compounds had a strong involvement in the antioxidant activity. FT-IR analysis demonstrated that the oxidation occurred during the brining process of the control sample. Peroxide value and 1H NMR analysis also showed extracted oil from olives treated with L. plantarum had more oxidation stability compared to untreated samples. In control sample, DSC analysis showed that the oxidation of oil sample increased during the storage period. Results also indicated that fermentation had positive effects on texture and color of olives. Therefore, fermentation can preserve quality of olive and olive oil during storage.