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

Abstract

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 50C 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) method followed 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.