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The present study evaluated the effect of fermentation with Lactiplantibacillus plantarum B7 and Bacillus subtilis natto on phenolic compound levels and enzyme activity, as well as antioxidant capacity of the rose residue. Results showed that the polyphenol content of rose residue was significantly increased from 16.37 ± 1.51 mg/100 mL to 41.02 ± 1.68 mg/100 mL by fermentation at 37 °C and 2.0% (v/v) inoculum size for 40 h. The flavone, soluble dietary, and protein contents were also enhanced by almost 1-fold, 3-fold, and 1-fold, respectively. Fifteen phenolic compounds were quantified in the fermented broth, among which the concentration of gallic acid, quercetin, and p -coumaric acid increased by 5-fold, 4-fold, and almost 8-fold, respectively. Chlorogenic acid was a new phenolic compound produced during fermentation. Moreover, the fermented rose residue presented higher superoxide dismutase, α-amylase, and protease activity. ABTS•+, hydroxylradical, and DPPH• scavenging activity increased by 60.93%, 57.70%, and 37.00%, respectively. This provides an effective means of transforming rose residue into a highly bioactive value-added substance. [Display omitted] [ABSTRACT FROM AUTHOR]

Diospyros lotus , a member of the Ebenaceae family, has long been used as a traditional sedative in China. In this study, the antioxidant and hypoglycemic effects of non-fermented and microorganism-fermented D . lotus were explored. The total phenolic and vitamin C contents of microorganism-fermented D . lotus for 24–72 h were less than those of non-fermented. High-performance liquid chromatography showed that the tannic, catechinic, and ellagic acid contents increased significantly upon fermentation for 24 h. D . lotus fermented with Microbacterium flavum for 24 h exhibited the highest DPPH radical scavenging activity (IC 50 = 4.18 μg mL −1 ), and the highest ABTS radical scavenging activity was exhibited at 72 h of fermentation (IC 50 = 29.18 μg mL −1 ). The anti-α-glucosidase activity of fermented D . lotus was higher (2.06–4.73-fold) than that of non-fermented one. Thus, fermented D . lotus is a useful source of natural antioxidants, and a valuable food, exhibiting antioxidant and hypoglycemic properties. [ABSTRACT FROM AUTHOR]