MODIFICATION AND EVALUATION OF AN ELECTRIC DRYER FOR HIGH MOISTURE VEGETABLES

Year 2018, Volume: 13 Issue: 1, 70 - 84, 19.01.2018

Mohammed Gana Yisa Adeshina Fadeyibi

Abstract

Food wastage resulting from
lack of facilities for drying and the unhygienic methods of processing are
major causes of food shortage in supply chain. Thus, to address these issues,
an existing electric dryer was modified for drying high moisture vegetables.
The machine was evaluated for drying tomatoes with an initial moisture content
of 63% (wb). A heating element was attached below the fan of the dryer to allow
a through air circulation instead of the cross air flow pattern of the previous
design. Four trays, with each having a capacity of 0.092m³, were
loaded with 30.4kg of slice tomatoes at a rate of 7.6kg per tray and dried for
5h. Thermostat was used to regulate temperature and relative humidity in the
drying compartment at 42^oC and 11% RH. Control experiment was set up
to determine the quality loss upon drying under sun for 5 h. Nutritional
quality parameters of the dried products were determined using standard known
methods. The results showed that actual volume of heated air delivered to the
drying chambers, thickness of polyurethane used as lagging and power requirement
for heating were 8.96m³, 38mm and 3000W, respectively. The
nutritional quality loss in the sun dried samples was lower than the
corresponding loss in the dryer. The modified dryer has 73% drying efficiency,
which higher than the efficiency of the existing dryer. 

Keywords

Design, Dryer, Performance, Tomatoes, Vitamin C, Vitamin C

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