The Effect of Hot-Air Drying Temperature on the Content of Major Bioactive Constituents and In Vitro Antioxidant Activity of Sanghuangporus vaninii

This study investigates the effect of hot-air drying temperature (45–70 °C) on the major bioactive constituents and in vitro antioxidant activity of artificially cultivated Sanghuangporus vaninii fruiting bodies. The contents of polyphenols and polysaccharides gradually rose with elevated temperature and peaked at 70 °C, whereas the flavonoid content reached the maximum at 55 °C and declined continuously afterwards. Among the tested bioactive substances, polyphenols exhibited the strongest antioxidant activity, with their DPPH and superoxide anion radical scavenging capacities peaking at 70 °C and hydroxyl radical scavenging capacity peaking at 55 °C. Correlation analysis revealed that the contents of polyphenol and polysaccharide possessed markedly positive correlations with DPPH and superoxide anion scavenging activities, yet no statistically relevant correlation was observed for flavonoids. Cluster analysis classified all tested temperatures into two clusters: low-temperature drying (45–50 °C) yielded inferior bioactive constituents and antioxidant activity, whereas medium-to-high-temperature drying (55–70 °C) delivered superior performance. From a practical perspective, drying at temperatures ≥55 °C is recommended to enhance product quality. Specifically, 70 °C is optimal to maximize overall antioxidant capacity, whereas 55 °C is preferable for flavonoid enrichment and color preservation. These findings provide an evidence-based strategy for the optimization of post-harvest drying processes of S. vaninii.