Drying kinetics and quality of Cissus quadrangularis Linn. dried by convective hot air

Abstract

This research aimed to develop a suitable drying model of convective hot air drying of Cissus quadrangularis Linn. (CQ), determine the effective moisture diffusivity of the drying process and the activation energy of CQ, and investigate the effects of different drying temperatures (40, 60, 80, and 100°C) on energy consumption and quality of dried CQ. The generalized linear-plus-exponential-type model proposed in this study could be used to describe the moisture data of hot air drying of CQ satisfactorily with an R² of 0.9957. The effective moisture diffusivity was in the range of 0.7302-9.1281 ×10^-9 m²/s. a positive relationship was observed between this parameter and drying temperature. The activation energy of CQ was 39.78 kJ/mol. The lowest energy consumption of 3.40 kWh was required when the highest drying temperature of 100°C was applied. The quality was well preserved when CQ was dried at a lower drying temperature. Drying at 60°C produced dried CQ with the lowest total color difference (16.76), shrinkage percentage (88.47%), and bulk density (0.1817 g/cm³) as well as the highest total phenolic (1062 mg GAE/100 g dry matter) and quercetin contents (0.955 mg/100 g dry matter).