Fermentation of olive pulp by Limosilactobacillus fermentum NCU001464: physicochemical properties, biological activity and bioactive phenols

Olives, which are rich in bioactive compounds, are processed into beverages in China. We investigated the effect of fermentation by Limosilactobacillus fermentum NCU001464 on the physicochemical characteristics, biological activities and phenolic compounds of olive pulp. After fermentation for 48 h, pH and individual sugar content of olive pulp decreased. Lm. fermentum NCU001464 fermentation enhanced the hydroxyl radical scavenging activity and the inhibitory effect against xanthine oxidase (XO) of olive pulp. Total phenol content was not significantly different between olive pulp fermented for 0 and 48 h. However, the fermented olive phenol extract had a lower IC50 value than the unfermented phenol extract. Fluorescence spectroscopy results revealed that the olive phenol extract had a stronger XO inhibitory effect after fermentation. The dominant binding forces between olive phenols and XO were hydrogen bonds and van der Waals forces. There were 31 different phenolic compounds between the unfermented and fermented extracts.