Investigation of kinetics of amla (Emblica officinalis) fruit drying process

Abstract

This study aims to investigate the kinetics of the amla fruit drying process using oven and sun drying methods. The experimental results indicate that the final moisture content dropped with increasing drying temperature and decreasing material size. Oven drying has a faster drying time than sun drying. The heat loss during oven drying is lower than during sun drying, so the drying rate constant (k) for the oven drying method is higher than for sun drying. Moisture ratios for each drying condition are evaluated using three thin-layer models: Handerson–Pabis, Page, and Newton. The coefficient determination (R2) was used as a statistical parameter to determine the best drying kinetics model. Among the drying models examined, the Page model had the highest accuracy. An increase in drying temperature and a decrease in material size caused the effective moisture diffusivity value (Deff) to increase. The Deff values ranged from 4.522×10−10 to 1.361×10−9 m2/s. Analysis using scanning electron microscopy showed that the microstructure of amla fruit was significantly affected by varied drying conditions.

Keywords

• Amla
• Moisture content
• Drying models
• Diffusivity
• Microstructure