Preparation, characterization and activity verification of xylooligosaccharides from plantain straw

Currently, the utilization value of plantain straw is low. To increase its value, plantain straw was utilized in this study to produce xylooligosaccharides (XOS). XOS were obtained from plantain straw through xylanase hydrolysis. The antioxidant and probiotic properties of XOS were also investigated. UV-Visible scanning showed no notable absorption peaks at 260 and 280 nm, indicating that the protein and nucleic acid in hemicellulose B were removed by the Sevag method. High-performance liquid chromatography revealed that hemicellulose B consists of L-guluronic acid, D-mannuronic acid, D-mannose, D-glucosamine, L-rhamnose, D-glucuronic acid, D-galacturonic acid, D-galactosamine, D-glucose, D-galactose, D-xylose, L-arabinose, and L-fucose. Xylose, galacturonic acid, arabinose, glucose, and rhamnose accounted for 35.04 %, 14.50 %, 13.63 %, 11.87 %, and 10.29 %, respectively. Scanning electron microscopy revealed that XOS displayed cross-linking and a rough surface. Fourier transform infrared spectroscopy analysis indicated that the oligosaccharides contained β-glycosidic bonds. Nuclear magnetic resonance analysis revealed that XOS contain methyl and methoxy groups and are linked by 1-4 glycosidic bonds. In addition, compared to hemicellulose B, XOS showed superior DPPH scavenging ability and higher reducibility. Antimicrobial activity analysis demonstrated that XOS from plantain straw exhibited beneficial probiotic effects on <i>Lactobacillus acidophilus</i> and <i>Bifidobacterium animalis</i>.