Pulsed vacuum drying of kiwifruit slices and drying process optimization based on artificial neural network

Abstract

In current work, the effects of drying temperature (60, 65, 70, and 75 °C), vacuum pressure duration (VPD; 6, 9, 12, and 15 min), and ambient pressure duration (APD; 2, 3, and 4 min) on drying kinetics and quality attributes of kiwifruit slices during pulsed vacuum drying (PVD) were explored. An artificial neural network (ANN) model combined with a comprehensive method was applied to evaluate the optimal drying condition. Results showed that drying parameters significantly affected the drying kinetics, color, and vitamin C content of kiwifruit slices except for rehydration ratio. The shortest drying time, i.e., 432 min, was obtained at a drying temperature of 75 °C, VPD of 12 min, and APD of 3 min. The lowest total color change (ΔE) occurred to dried products at 65 °C, VPD of 12 min, and APD of 4 min. The vitamin C content of dried product decreased with the increase of APD. The optimal condition predicted by ANN was 65 °C, VPD of 12 min, and APD of 2 min, which obtained the highest comprehensive score of dried kiwifruit slice. The relative error percentage between the predicted and experimental compressive score at optimal condition was 2.92%.