Structural characterization, functional properties, and antioxidant potential of a novel mannogalactoglucan from Boletus auripes peck

Polysaccharides from Boletus auripes Peck exhibit high nutritional value and bioactivity, but insufficient understanding of its detailed structural information, physicochemical, and functional properties severely limits its wide application in food industry. In this work, an antioxidant polysaccharide (BAHW-1) was prepared from B. auripses. This study further investigated its precise structure, physicochemical and functional properties, as well as the health-promoting potential in preventing reactive oxygen species (ROS). Structural analysis indicated that it is a highly branched heteropolysaccharide with the backbone consisting of →4)-α-Glcp-(1→, →3,4,6)-α-Glcp-(1→, →4,6)-α-Glcp-(1→, →6)-α-Galp-(1→, and →2,6)-α-Manp-(1→, and five branched chains. Additionally, this polysaccharide exhibits excellent functional properties, including water-holding, fat-binding, foaming, emulsion, rheological and thermal properties. The growth kinetics of probiotic strains revealed that the prebiotic potential of BAHW-1 was comparable to that of GOS-P and glucose. Importantly, BAHW-1 shows strong antioxidant activity and significantly reduces the calcium salt deposition in mouse kidneys by inhibiting ROS and the downstream TGF-β1-Smad2/3-Sox17 pathway, thereby providing effective renal protection. Therefore, this natural antioxidant polysaccharide could potentially be developed as a nutraceutical or functional food.