Dehydration studies of sweet pepper (Capsicum annum. L)
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Date
2004-07
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Sweet Pepper (Capsicum annum. L, grossum group) is a non pungent variety of pepper (capsicum sp) locally known as simla mirch. It is also famous as bell pepper is vegetable in India. It is globally so popular because of its anti cancerous and antioxidant qualities. Sweet peeper is also good source vitamin C and vitamin E. Due to high moisture content at the time harvesting it is very difficult to store the sweet pepper. The experiments were conducted to develop dehydrated Sweet pepper. In the present investigation Sweet pepper slices were blanched with hot water at 95oC for 5 min. Pretreatment was carried out by dipping in 1% NaOH solution with 0.25% MgCO3 for 15 min at room temperature. The ratio of sweet pepper to pretreatment mixture was 1:5 and exposed to single thin layer drying with constant air velocity 1.5 m/s and temperature from 40 to 70oC with an increment of 50C. Experiments also conducted to study the effect of drying on quality, colour, chlorophyll, ascorbic acid, Rehydration and shrinkage characteristics. The selected drying models were attempted on experimental data to describe the phenomena of drying process using linearzed regression technique. Moisture content of the fresh sweet pepper was an average of 92 % w b and seed to flesh ratio of sweet pepper is 1.56. Drying of sweet pepper takes place in falling rate period. Drying rate linearly increases with temperature and effect of blanching was predominant. The drying curves could be mathematically described by the logarithmic model. The rehydration ratio increases with drying air temperature up to 600C; than it was found that decreasing with increase in temperature and effect of blanching on rehydration ratio was significant. Colour of the samples decreases as increase in temperature as blanched samples showed significantly in retaining colour. Chlorophyll content and ascorbic acid of the samples decreases as increase in temperature. Blanched samples showed significantly in retaining in Chlorophyll content and ascorbic acid. Shrinkage ratio increase with temperature as shrinkage reduces with temperature. Sweet pepper should not be dried more than 600C temperature, because of high temperature significant reduction in colour, chlorophyll and ascorbic acid was very high. Medium temperature (50-600) should be used for dehydration where as blanching will improve the quality of the sweet pepper.
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