Preparation, characterization, antioxidant activity evaluation and application of high-thickening instant Tremella...

Tremella fuciformis polysaccharides (TP), a natural polysaccharide with dual medicinal and edible values, possesses excellent gelling properties, water-holding capacity, and biological activities, rendering it a promising thickening agent for dysphagia-friendly foods. However, its poor solubility and tendency to agglomerate severely limit its practical applications. To overcome this limitation, the present study developed two optimized processing techniques: fluffy tablets prepared by heating at 95 °C (named TPS1, where S stands for fluffy tablets) and tablets treated with a single cycle of high-pressure homogenization at 3 MPa (TPHP1). Their dissolution times were 211.29 ± 4.32 s and 169.07 ± 7.55 s, respectively. Both methods significantly enhanced the instant solubility and thickening capacity of TP. Notably, this study is the first to classify instant TP products under the International Dysphagia Diet Standardization Initiative (IDDSI) framework. Structural characterization results indicate that high-pressure homogenization treatment significantly reduced the number-average molecular weight of TP from 5087.33 kDa to 1538.90 kDa, while broadening the molecular weight distribution range. Meanwhile, the porous structure formed by TPHP1 provided a structural basis for the enhanced instant solubility of TP. Antioxidant activity testing showed that the IC₅₀ values of TPHP1 for scavenging DPPH radicals, ABTS radicals, and hydroxyl radicals were 1.58 ± 0.279 mg/mL, 0.87 ± 0.079 mg/mL, and 1.02 ± 0.065 mg/mL, respectively, all superior to those of TPS1 (1.73 ± 0.045 mg/mL, 1.49 ± 0.064 mg/mL, and 1.41 ± 0.074 mg/mL, respectively). Rheological property analysis and application evaluations indicated that TPS1 could stably meet IDDSI Levels 1-3 at concentrations of 4-12 mg/mL. TPHP1 achieved the same stability at concentrations of 8-12 mg/mL. Sensory evaluation results indicate that TPS1 exhibits excellent oral cohesiveness, propulsive force, and lubrication adaptability in practical food matrices such as milk and turtle peptides. TPHP1, on the other hand, excels in lubrication and propulsive force, making it suitable for meeting the sensory requirements of low-viscosity beverages. Research indicates that TPS1 possesses high polysaccharide retention and structural stability, making it suitable for general-purpose medium-viscosity dysphagia foods. TPHP1 offers superior instant solubility, enhanced antioxidant activity, and outstanding shear stability, positioning it as ideal for low-viscosity functional beverages. This study provides theoretical foundations and practical support for the high-value application of TP in functional foods and dysphagia diets, offering new solutions for dietary management in special populations.