Influence of Drying Temperature on Quality Characteristics and Drying Kinetics of Siraitia grosvenorii Fruit

Siraitia grosvenorii fruit, a traditional medicinal and edible plant, undergoes significant alterations in quality and bioactive composition during the dehydration process. This study investigated the effects of hot-air drying at various temperatures on the physicochemical properties, antioxidant activity, and drying kinetics of S. grosvenorii fruit. The drying process was terminated when fruit moisture content reached 15%, with corresponding drying durations of 420, 225, 144, 96, and 51 h at 40 °C, 50 °C, 60 °C, 70 °C and 80 °C, respectively. Among the ten mathematical models evaluated, the Midilli-Kucuk model provided the most accurate description of the drying kinetics of S. grosvenorii fruit. Quality analysis revealed that drying reduced the sugar/acid ratio, contents of mogrosides and ascorbic acid, while increasing total phenolic and flavonoid levels. Microstructural analysis revealed that higher temperatures increased drying rates by expanding the porosity of the pulp. Based on the retention of bioactive components and antioxidant capacity, 70 °C was identified as the optimal drying temperature. Overall, these findings suggest that oven-drying optimizes drying efficiency and ensures the retention of essential bioactive constituents in S. grosvenorii.