Kinetic studies for the preparation of probiotic cabbage juice: Impact on phytochemicals and bioactivity

A kinetic study for the production of probiotic cabbage juice was carried out under controlled pH and dissolved oxygen using several strains of lactic acid bacteria (LAB). Furthermore, effect of probiotic fermentation on polyphenolic content and antioxidant capacity was investigated. Results showed significant growth in Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus rhamnosus corresponding to 9.19, 9.47 and 10.6 log CFU/ml after 24 h of fermentation, which is satisfying criteria for a food product to be characterized as probiotic. Lactic acid (LA) was the major end product of the fermented cabbage juice attaining the concentrations of 6.97, 9.69 and 12.2 g/l LA for L. plantarum, L. rhamnosus and L. brevis, respectively. LAB fermentation retains more than 75% of total phenolic content (TPC) and total flavonoid content (TFC) of the initial raw material, and similar set of results were observed for antioxidant capacity. First-order kinetics model fitted well with the experimental data with R2 value ranging from 0.92 to 0.96, 0.96 to 0.98 and 82.2 to 97.2 for TPC, TFC and antioxidant capacity, respectively. During refrigerated storage (4 °C), all the probiotic cultures met the criterion of maintaining counts greater than 8 log CFU/ml; in addition to maintaining bioactive components and antioxidant capacity.