Antioxidant activities and volatile compounds of Chinese cabbage sauce prepared by the combination of Lactobacillus plantarum and functional oligosaccharides

The effects of Lactobacillus plantarum fermentation and addition of fructooligosaccharide (FOS), galactooligosaccharide (GOS) or isomaltooligosaccharide (IMO) on the antioxidant activities and volatile compounds of Chinese cabbage sauces prepared with salt or chilli powder were investigated. Lactobacillus plantarum exhibited excellent growth ability in cabbage sauces and the colony counts remained above 7.70 log CFU/mL throughout the fermentation process. Addition of FOS and GOS significantly promoted Lactobacillus plantarum proliferation remaining above 8.13 log CFU/mL at the end of fermentation. In addition, contents of total phenolic and flavonoid were significantly increased at the end of fermentation, especially for spicy cabbage sauce with oligosaccharides addition. Quercetin content was increased by 88.51% in cabbage sauce after Lactobacillus plantarum fermentation. DPPH radical scavenging activity and FRAP of cabbage sauces were improved by Lactobacillus plantarum fermentation. Contents of gallic acid, caffeic acid, and p-coumaric were positively correlated with antioxidant activities (p < 0.05). Furthermore, a total of 81 volatile compounds were detected in cabbage sauce before and after fermentation, including 22 alcohols, 15 esters, 14 terpenes, 10 ketones, nine hydrocarbons, six aldehydes, three nitriles, and two acids. Total contents of alcohols, esters and ketones were increased by Lactobacillus plantarum fermentation. Terpenes, as new compounds, appeared in fermented cabbage sauce, especially for the fermented spicy cabbage sauces in the range of 1179.98–2428.27 μg/L. Hierarchical cluster analysis indicated that Lactobacillus plantarum fermentation and oligosaccharides addition exhibited positive effects on the formation of volatile substances in Chinese cabbage sauce.