Profile drying: A novel multistage convection drying method for indian dark red onion slices

Abstract

Drying increase shelf life and preserve nutritional value. Convection drying experiments are conducted at different novel multistage drying profiles and at constant 60°C temperature. Velocity varied in the range of 2, 3.6, 5.7, and 7.7 m/s for the dark Indian dark red onion. The objective is to analyse the multistage novel convection profile drying method for onion slices at high velocity. The constant 60°C air-drying process consumes 18.88% to 34.98% more energy than multistage drying profiles for the 360 minutes of convection drying. The arithmetic mean of effective moisture diffusivity lies between 1.002396 × 10-12 to 7.898936 × 10-11. A better drying rate is found for constant 60°C constant temperature, but higher activation energy (1.23710647 to 1.8186585 kJ/mol) is required than drying profiles. The rehydration ratio of the profile is observed to be higher and rises uniformly with time compared to a constant 60°C. In the proximate analysis, it was observed that crude FAT, Carbohydrate, total energy, Potassium, and Calcium contents are increased on the onion’s drying. Total ash content and total mineral content were detected to be decreased with drying.