Improvement of Antioxidant Activities in Red Cabbage Sprouts by Lactic Acid Bacterial Fermentation

In the present study, the influence of three types of lactic acid bacteria (Lactobacillus plantarum ATCC 8014, Lactobacillus acidophilus NCFM, Danisco, and Lactobacillus rhamnosus GG E522 (ATCC 53103)) on antioxidant activities of fermented red cabbage sprouts was determined and compared with those of their unfermented/control counterparts. The fermentation resulted in a significant increase (p < 0.05) of antioxidant functionalities as measured by four assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging, Trolox equivalent antioxidant capacity (TEAC), superoxide dismutase (SOD)-like, and -carotene/linoleic bleaching. The most considerable shift in the antioxidant activities was observed after 24 h of fermentation. These increases were followed by a decrease in total phenolic compounds, anthocyanins, and L-ascorbic acid and by an increase in flavonoids, flavonols, and several phenolic acids (gallic, chlorogenic, caffeic, syringic, p-coumaric, trans-3-hydroxy-4-methoxycinnamic, and trans-o-hydroxycinnamic acid) content. The relationship between the antioxidant activities and the compositional changes in antioxidant compounds due to LAB fermentation was observed. Fermented red cabbage sprouts inoculated with L. plantarum had the highest antioxidant activities (DPPH scavenging: 70.92%; TEAC: 1.94 mM Trolox equivalent; SOD-like activity: 63.40%, and -carotene/linoleic bleaching: 44.33%), which was almost two-fold higher than those of unfermented treatments. These results indicated that LAB fermentation could be applied as a method to improve the potent antioxidant activities of red cabbage sprouts.