The effect of sun and shade drying on chemical composition of Vitex doniana, Ipomoea aquatica and Cohcorus and their soups

This study investigated the effect of sun and shade drying on chemical composition of African black plum “Uchakoro” (Vitex doniana) Bush okro leaf “Ewedu” (Corchorus) and wild lettuce “yaririn” (Ipomoea aquatica) vegetables and their soap meals. These vegetables were bought in bulk from Ibaji Local market in Kogi State, Nigeria. The foods were washed with clean water, plucked from the stalk, sun and shade dried to mimic the traditional food processing techniques. The fresh vegetables served as the controls. A portion of each processed vegetable was pulverized, sieved, packaged in name labeled polythene bags and kept in cool dry place until used for various chemical analysis. The other portions as well as the fresh vegetables were used to prepare various traditional indigenous soup meals using similar consistency traditional recipes for each soup. The chemical composition of both the vegetables and their soups were determined using standard assay methods on dry matter basis. Means, standard deviation and least significant difference (LSD) were adopted to separate and compare means from data generated. The protein, ash, fat and fibre values for both the sun and the shade dried vegetables were higher than those of fresh samples (P<0.05). The fresh vegetables had higher calcium, iron and zinc than the sun and the shade dried vegetables. On the other hand, sun and shade drying decreased beta carotene and ascorbate as against those of the fresh samples. The protein, ash, fat and carbohydrate values for soups prepared with dried vegetables were much higher than those of their controls. The soups prepared with dried vegetables had lower iron, calcium, zinc and iodine than those prepared with fresh vegetables (P<0.05). The higher, iodine, zinc, beta carotene and ascorbate values for shade dried samples regardless of the types of vegetables indicated that shade drying had an edge over sun drying as traditional food processing technique to preserve nutrients in these vegetables.