Pressure-controlled steam explosion as pretreatment for efficient extraction of Tremella fuciformis polysaccharide: Structure and bioactivity

Tremella fuciformis (TF) is a mushroom with rich nutritional and medicinal value. This study aimed to develop an efficient extraction technique for TF polysaccharide (TFP) to enhance its health benefits. TF was subjected to steam explosion (SE) pretreatment at 0.5, 1.0, and 1.5 MPa for 60 s, followed by polysaccharide extraction. The extraction yield of TFP increased from 15.42 % to 50.16 % at 1.0 MPa. SE disrupted the dense structure of TFP, significantly improving total sugar and uronic acid contents, monosaccharide molar percentages of mannose and glucose, specific surface area, and ζ potential by 0.16, 0.4, 0.01, 0.83, 0.19, and 0.26 times at 0.5 MPa (P < 0.05). With increasing SE pressure, the thermal stability of TFP was enhanced, while its elasticity, viscosity, molecular weight, and particle size were reduced. TFP at 0.5 MPa significantly extended the lifespan of Drosophila melanogaster, with T_max reaching 74 d for females and 60 d for males at a dosage of 0.015625 %, indicating a 0.32-fold enhancement. TFP enhanced climbing ability and antioxidant stress resistance, increased antioxidant enzyme activities and total antioxidant capacity, and reduced malondialdehyde levels, indicating its anti-aging effects. These findings provide theoretical and technical support for the high-value development and utilization of TFP.