ABSTRACT

The study evaluated the effect of drying; methods on nutrients and chemical composition of Spinacia oleracea (spinach) and Brassica oleracea L. (cabbage). The two vegetables were purchased from local market in Ahia-Eke, Local Government Area, Abia state, Nigeria in bulk. These two vegetables were washed, cleaned, plucked from the stalk and processed to mimic traditional methods of preserving vegetables. The vegetables were divided into three equal portions. The first portion served as the control (Fresh), the second and third portions were sun and oven dried. The dried samples were packaged in a cellophane bag for analyses of proximate, mineral, vitamin, and sensory qualities using standard methods. The chemical composition of the vegetables was determined using current standard methods. Results obtained showed that sun and oven drying drastically reduced moisture content of the vegetables when compared to the controls (84.73-16.23, 6.46 and 88.19-10.39, 7.38%). The protein for the sun and the oven dried samples were higher than those of the controls (1.88 and 1.79 vs 4.76, 4.54 and 3.60 and 3.33%, respectively) (p<0.05). Ash, fat and fibre content of the dried samples were also higher. Carbohydrate values for the two vegetables were extremely high and comparable (295.12 and 320.84%) than those of the controls. Drying comparably increased energy from 47.98- 295 and 337 kcal, each. Sodium, potassium, calcium, magnesium and phosphorus of the fresh samples were higher than those of the dried samples. The vitamin content showed significant difference (p < 0.05) in the level of vitamin A and C. Fresh vegetables had higher vitamin A and vitamin C than that of the oven and sun-dried samples. Drying equally decreased oxalate and tannins relative to their controls. The result of this study suggests that sun drying method was a better processing method in terms of nutrient retention and anti-nutrient reduction than oven drying method.  Going by the nutrient quality on both plants, it can be used as a supplement in human and animal meals for improved nutrition.