Experimental research on the drying process of pear and mango slices in hot air and supper heated steam agents ☆

Drying is an area that consumes a lot of energy and degrades the nutritional components of dried products if the right drying mode is not chosen. The drying process in different drying agent environments is being studied to find the right drying mode to increase product quality, reduce drying time, and reduce energy consumption. In this study, the drying processes of common agricultural products, namely pear slice and mango slice are conducted in a lab-scale dryer using hot air and superheated steam. Experimental calculation models are established, and product quality will be studied in several aspects including color change and shrinkage to comprehensively evaluate the applicability and suitable drying conditions for pears. The empirical models are built based on the Newton model which give the good agreement results in compared with the experimental model. For both fruit kinds, color of products obtained from superheated steam drying is darker than that from hot air-drying exception of at 110oC, while the porosity of dried product in superheated steam is higher than dried product in hot air. The research results are the basis for expanding the application ability of modulated gas and superheated steam for post-harvest processing technology.