Comparative evaluation of sun, solar cabinet and electric cabinet drying methods for drying of lesser known leafy vegetables in Jharkhand

Leafy vegetables are the most important diet component of different tribal and local communities of Jharkhand as they are rich source of nutrients and micronutrients. Most of the leafy vegetables are highly perishable. Drying reduces the moisture content to a safety level and allows storage over a long period. In the present study, performance of thee drying methods viz. conventional sun drying (SD), solar cabinet dryer (SCD) and electric cabinet dryer (ECD) were evaluated in drying of six lesser known leafy vegetables viz., Moringa oleifera, Polygonum plebeium, Centella asiatica, Limnophila conferta, Bauhinia variegata and Amaranthus viridis. Study revealed that in SCD the average temperature was 5°C higher over SD method which allowed faster removal of moisture from the vegetable leaves. Among the three drying methods, ECD was the fastest (drying time 2.2–3.0 hr) methodfollowed by SCD and SD(3.4–10.0 hr) methods. Initially, moisture content decreased at faster rate which was slowed down gradually with time. Drying rate constant was higher for SD (0.12–0.50 hr⁻¹) followed by SCD (0.03 0.20 hr⁻¹) and ECD (0.0002–0.014 hr⁻¹) methods. The rate of drying efficiency was recorded highest in ECD method followed by SCD and SD methods irrespective of all the leafy vegetables. Keeping in view the erratic power supply, drying time, hygiene and safety, SCD can be better alternative to sun drying. On the basis of portability and cost effectiveness, the solar cabinet dryer is recommended for small farmers of the Jharkhand.