Aims The influence of bacterial species/strains in agitated culture was investigated on the morphology and structure characteristics of bacterial cellulose. Methods and Results Komagataeibacter nataicola Y19 and Gluconacetobacter entanii ACCC10215 were inoculated in Hestrin–Schramm (HS) medium and subjected to agitated cultivation. Different kinds of BCs were obtained including flocky asterisk‐like BC by G. entanii ACCC10215 and solid sphere‐like BC by K. nataicola Y19. The SEM results showed that the asterisk‐like BC had larger pores than the solid sphere‐like BC. The FT‐IR and X‐ray diffraction results showed the asterisk‐like BC had lower crystallinity (81·43%), higher cellulose Iα mass fraction (79·74%) and smaller crystallite size. Conclusions The different species/strains can influence the morphology and structure characteristics of BC in agitated culture. Significance and Impact of the Study We examined the influence of different species/strains on the morphology, macro‐ and microstructure of BCs produced in agitated culture for the first time, which suggest that different BCs with potential applications could be obtained by choosing different species or strains and fermentation method.
Free and bound phenolic fractions from six buckwheat varieties were investigated for their compositions, antioxidant activities, and inhibitory effects on α-glucosidase. The results showed that different buckwheat varieties have significant differences in phenolic/flavonoid contents, and these contents were found in higher quantities in free form than in bound form. HPLC results revealed that rutin, quercetin, and kaempferol-3-O-rutinoside were the most abundant components in free and bound forms, whereas dihydromyricetin was found only in the bound form. Free phenolics showed higher antioxidant activities of DPPH, ABTS+, OH•, and FRAP than those of bound phenolics. Strong inhibitory effects against α-glucosidase by the free/bound phenolic fractions were found in all buckwheat varieties, and free phenolics showed stronger α-glucosidase inhibition than that of the corresponding bound phenolics. More importantly, the main phenolic compounds observed in the buckwheat varieties were subjected to molecular docking analysis to provide insight into their interactions with α-glucosidase. The contributions by individual phenolics to the observed variation was analysed by Pearson correlation coefficient analysis and principal component analysis. The present study provides a comprehensive comparison for the phenolic fractions of buckwheat varieties and identify the main contributors to antioxidant and α-glucosidase inhibitory activity.