Hot air drying of horseradish: empirical drying kinetic modeling and physical quality characteristics of dried horseradish

Abstract

The main objectives of this study were to dry horseradish at 50, 70 & 85˚C using hot air convective dryer for characterizing the drying kinetics and to observe the effects of blanching and drying temperatures by comparing the physical properties (moisture content, color, water activity, piece density and rehydration capacity) of dried horseradish. The drying kinetic data were fitted in 8 empirical models to characterize the drying rate of horseradish. Blanching and drying temperature significantly affected (P<0.05) the quality of the dried horseradish. Brightness value of the dehydrated horseradish was inversely proportional to the drying temperature and unblanched samples exhibited higher brightness as compared to blanched samples. Minimum color difference was found in the unblanched samples dried at 70˚C. There was no significant difference in the piece density for controlled samples dried at different temperatures. Blanched sample dried at 50˚C exhibited significantly higher rehydration capacity. Water activity decreased with increased drying temperature. Page model and Diffusion approach model were the best fitted models to characterize the dehydration of horseradish at different drying conditions. The findings of this research are expected to be significantly important for the scientists and engineers who are interested to design the drying process of horseradish.