PERFORMANCE EVALUATION OF LOW COST MULTIPURPOSE GREENHOUSE FOR DRYING OF TOMATO
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Date
2019
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Publisher
Birsa Agricultural University, Ranchi, Jharkhand-6
Abstract
Tomato (Lycopersicon esculentum Mill.) is a highly seasonal, perishable and available
in large quantities during peak season of production. It is an important vegetable for
human consumption because of its vitamins and minerals content that provide the basic
human nutritional requirements. There are various techniques of extending shelf life of
tomato and dehydration is one of the important process by which tomatoes are
preserved. The greenhouse is an enclosed structure and inside temperature is more than
open field and can be used as direct solar dryer.
The low cost multipurpose greenhouse (MGH) was used for drying of without
blanched & blanched tomato under full and half ventilation condition. The construction
cost of low cost MGH was around Rs 290/m2. The environmental parameters
temperature & RH under full ventilation and temperature, RH & air velocity under half
ventilation was recorded during drying of tomato. All the environmental parameters
were measured at 1 h interval. The initial moisture content of fresh tomato was found to
be 93.3% - 94.4 % (w. b.) and the blanching was done by dipping the cut tomato in
sodium metabisulphite solution (6%) for blanching time of 5 minutes.
The temperature & RH measured at full ventilation under MGH was found to be
3°C to 8.5°C more than open field condition and RH was found to be 5% to 7% lower
than open field. The temperature variation at different location measured at along the
length, width & height inside the MGH and the highest temperature was found to along
the height at the 2.7 m. The final moisture content of dried tomato samples was around
11% (w. b) and the drying time of tomato at full ventilation for without blanched &
blanched under open field condition is 29 h & 20 h whereas under MGH condition for
without blanched & blanched tomato is 28.5 h & 19.5 h.
The shrinkage ratio, rehydration ratio & dehydration ratio of dehydrated tomato
under full ventilation were varied between 13.5 to 14.48, 1.7 to 1.8 & 12.68 to 13.3
respectively. The sensory evaluation was performed using Hedonic-rating test of 5-
point scale and the blanched tomato dried under MGH was found to be best in
comparison to open field. The MGH is used for drying of tomato apart from cultivation
& cost efficient than stand alone greenhouse solar dryer constructed only for drying
purpose.
Description
PERFORMANCE EVALUATION OF LOW COST MULTIPURPOSE GREENHOUSE FOR DRYING OF TOMATO
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