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%.

Keywords:

• Kiwifruit
• pulsed vacuum drying
• color
• vitamin C
• artificial neural network
• comprehensive evaluation method
• SEM
• heat map

Additional information

Funding

This research is supported by the National Key Research and Development Program of China (No.2017YFD0400905) and the basic scientific research program for public welfare scientific research institutes in Xinjiang Uygur Autonomous Region (KY2019027). Moreover, Dr. Zi-Liang Liu thanks the China Scholarship Council (No. 201906350100) for supporting his oversea research at University of California, Davis.