Changes in functional components and biological activity of Lycium barbarum after fermentation with Kombucha SCOBY

Abstract

Kombucha, fermented via symbiotic colony of bacteria and yeast (SCOBY) with black tea, is applied as a nova microbial method for processing traditional Chinese medicine (TCM). In this study, Lycium barbarum was used as the substrate combined with Kombucha SCOBY to enhance its antioxidant activities and flavor composition. The result indicated that the antioxidant activities of L. barbarum fermentation broth (LBF) was increased and 16.51% higher compared to the infusion. Besides, the inhibition zone of LBF on the 10th day against Escherichia coli and Staphylococcus aureus reached the maximum of 18.80 and 21.85 mm. Three typical L. barbarum polysaccharides, including LBP1, LBP2, and LBP3, were extracted and their compositions were identified. Among them, the DPPH scavenging rate and reducing power of LBP2 were 67.36% and 0.612 which were both higher than others. Furthermore, SOD enzyme and cellulase activity of LBF on 10th day were improved by 92.41% and 2.27 times, respectively. Thirty-one aroma compounds were determined in Lycium barbarum Kombucha ferment via GC–MS. The strongest flavor of the LBF was sourness while the weakest flavor was saltiness which was analyzed through the electronic tongue. Our research provides a theoretical basis for the development of functional L. barbarum Kombucha product and explores the application of Kombucha SCOBY in processing TCM. Novelty impact statement The fermentation of Kombucha combined with Lycium barbarum with respect to antioxidant and bacteriostatic activities was enhanced prominently. L. barbarum polysaccharides, including LBP1, LBP2, and LBP3, were first identified with nine monosaccharides closely related to biological activity. Aroma compounds of organic acids with sourness flavor made a biggest contribution to L. barbarum Kombucha ferment.