Abstract
STUDY OF DEHYDRATED CURVES OF RADISH AND PURSLANE LEAVES
Abdul Sabir*, Vellenki Bhaskar, Srinivas Maloo and Dr. Kavita Waghray
ABSTRACT
Dehydration of leafy vegetables project is a new product of value addition series where the shelf life is increased & space for storage is reduced along with easy transportation. If dehydrated leafy vegetables are managed efficiently, we can earn good revenue in the form of foreign exchange by exporting dehydrated vegetables which will indirectly improve the status of farming community. Drying time and drying conditions are important factors in dehydration of leafy vegetables. Thus the study of drying behaviour has been the subject of intense investigation as the mechanism of moisture transport are so varied with types, maturity, drying modes, pre-drying stages adopted. Moreover the mechanism of drying foods is not as simple as perceived and follows the constant rate and falling rate periods. In constant rate period of drying, the surface temperature of food remains near to the wet bulb temperature of surrounding air. Hence rate of drying can be easily worked out for this period. However during falling rate period due to additional resistance, which vary with the type of product, plays significant role in moisture transfer. This internal resistance to moisture transfer becomes limiting in selecting the process equipment as well as operating parameters. This of data for vegetables is not readily available. Hence the present study was undertaken to find out dehydration behaviour of selected vegetables. The dehydration kinetics revealed that the moisture content decreased very rapidly during the first hour of drying with sun drying requiring about eight hours and mechanical drying about four hours to reach the desired moisture level of 9-11 per cent. The dehydration processes not only affects the colour and other pigments but also the sensory attributes like colour, appearance, texture, aroma and overall quality to a varying degree. These variations depend not only on the type of vegetable but also on the method of processing.
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