Changes in nutritional composition, volatile organic compounds and antioxidant activity of peach pulp fermented by lactobacillus

Fermentation with lactobacillus offers a natural means to modify nutritional and flavor properties of foods, and strains have crucial effects on it. In this study, peach pulp was fermented by five commercial probiotics (L. plantarum 21802, L. brevis 6239, L. pentosus 21798, L. alimentarius 21852 and L. pentosus 21832) to screen out a strain with higher adaptability ability and polyphenol bio-transformation capacity. Then, dynamics changes in microbial properties, nutritional composition, volatile organic compounds and DPPH radical-scavenging activity of peach pulp fermented by selected strain were studied and compared with the control sample. HPLC, LC-ESI-MS/MS and GC-MS were used for identification and quantification of phytochemistry. Results showed that the most efficient strain was L. plantaurm 21802 caused a significant (P < 0.05) increase in microbial population and total phenol content of peach pulp, which leads to an obvious decrease in fructose and glucose and a great increase in lactic acid content after 60 h fermentation. The malolactic conversion was completed within 12 h. Moreover, it caused an increase in β-carotene (14.82%), as well as chlorogenic acid (154.00%), vanillic acid (95.44%), epicatechin (27.99%), quercetin-3-O-glucoside (124.19%) and isorhamnetin (438.29%). Furthermore, lactobacillus fermentation resulting in the improvements of alcohols and aldehydes production, and the contents of four key aroma compounds (OVA>1), namely linalool, benzaldehyde, damascenone and eugenol, increased significantly (P < 0.05). These findings evidenced the potential use of L.plantarum 21802 in peach pulp fermentation for improving the nutritional and functional properties, and proved a possibility of peach fruit as a novel material for functional plant-based fermentation beverages.