Effects of Hydrocolloids Coating Pretreatment on the Drying Kinetics and Quality Attributes of Heat Pump Dried Scallop Adductors

In order to improve the heat pump drying efficiency of scallop adductors and improve the quality of dried products, the effects of low methoxy pectin (LMP) and chitosan (CTS) on drying kinetics and quality characteristics (texture, rehydration rate, shrinkage rate, color) of scallop adductors were investigated. The results showed that moisture content of scallop adductors was decreased with increasing drying time. The drying process of scallop adductors was in the falling rate stage, and the drying process was controlled by internal water diffusion. The drying rate was increased by LMP and CTS treatments. Compared with CK, LMP and CTS pretreatment could increase the effective water diffusion coefficient by 11.08% and 26.73%, respectively. Compared with CK, LMP treatment reduced the shrinkage rare, total color difference, hardness and toughness of scallop adductors, and improved the rehydration rate of dried products. CTS treatment decreased shrinkage rate, and enhanced the rehydration rate, toughness and hardness, but showed no effect on total color difference. Eight mathematical models were used to fit the drying kinetics data. The Midilli et al. was the most suitable model to describe the drying process of scallop adductors. Hydrocolloid’s coating pretreatment has a significant effect on improving the drying efficiency of scallop adductors during heat pump drying and enhancing the quality of dried products. The findings provide theoretical basis and practical reference for heat pump drying of aquatic products.