Comparative studies of sun and solar drying of peeled and unpeeled ginger

Abstract

Fresh ginger rhizomes were washed, sorted and cut into desired sizes using a knife. Some were peeled to remove the cork skin while others were left unpeeled with the cork skin. The samples were dried in a solar dryer and the open air for two weeks and designated; solar peeled and unpeeled, and open-air peeled and unpeeled Some physico-chemical and organoleptic analyses were carried out on the samples before, during and after drying. The results obtained showed that open-air dried products retained its colour and aroma more than the solar dried samples. Drying was faster with the solar dryer than with the open air method. While the Total variable count (TVC) on the dried ginger was reduced to 66.7% for peeled and 57.6% for unpeeled ginger in the samples subjected to open-air drying, it was reduced to only 47.6%for peeled and 9.63% for unpeeled with solar drying method. The moisture content of the solar dried unpeeled ginger was reduced to 7.0% which is within the standard of 6-9% acceptable to the international market unlike that of open air drying which could only attain about 17.0% moisture content in the study area. Although there was no defined trend in changes of crude protein content of samples with drying time, solar dried ginger appeared to contain less protein than air-dried ones. Keyword: Solar drying, Agricultural product, ginger, preservation