Tomato juice was fermented by Lactobacillus plantarum and Lactobacillus casei to produce an innovative high-bioactivity probiotic beverage. The levels of lycopene, total carotenoids, ascorbic acid, total phenolic and volatile compounds, 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzotiazo-line-6-sulfonic acid (ABTS) radical scavenging capacities, ferric reducing antioxidant power (FRAP), and Escherichia coli flora, as well as the inhibition of copper-induced human low-density lipoproteins (LDL)-cholesterol oxidation assays, were measured. The results revealed that the ABTS and DPPH inhibition values, as well as the FRAP and total phenolic content, were significantly increased. LDL-cholesterol oxidation was markedly delayed after the addition of the fermented juice. The in vitro inhibitory effects of Escherichia coli flora were substantially increased after being fermented with Lactobacillus plantarum and Lactobacillus casei. The results associated with the volatile compounds indicated that fermentation with Lactobacillus plantarum and Lactobacillus casei is a meaningful strategy for modifying flavors.
Keywords: Escherichia coli flora; Lactobacillus casei; Lactobacillus plantarum; antioxidant activity; tomato juice; volatile compounds.