Mitigating Browning and Improving Texture Issues in Persimmons: The Impact of Freezing Pretreatment on Vacuum Microwave Drying

Xiaoxian Tang¹Min Zhao¹Aiqing Ren¹Zhenhua Duan¹Yan Liu¹Zhaokun Xian^2*

• ¹Hezhou University, Hezhou, China
• ²Guilin University of Technology, Guilin, China

Vacuum-microwave drying can induce browning, charring, and the formation of surface wrinkles and collapse in persimmons, thereby significantly diminishing product quality. To mitigate these issues, this study proposes a freezing pretreatment strategy with an optimized freezing temperature of -80°C. The effects of this pretreatment on persimmon slices were evaluated across multiple dimensions, including appearance, physical properties, processing and quality indicators, sensory texture characteristics, and pore structure. The results indicate that freezing pretreatment enhances the color uniformity of persimmon slices by 64.5% and reduces the browning index growth rate by 21.4%. Furthermore, the expansion rate and rehydration capacity increase by 15.7% and 21.5%, respectively, while hardness and chewiness decrease by 84.4% and 91.6%, and crispness is enhanced by 40.4%. This study integrates freezing pretreatment with VMD, effectively addressing the challenges of browning and texture degradation. These findings present a promising approach for producing high-quality persimmon crisps, and future research should investigate the optimal freezing duration and temperature, as well as extend this technique to other fruits and vegetables.