ABSTRACT

This study was carried out to determine the effect of different processing methods on the nutrient and anti-nutrient content of Dioscorea bulbifera. The Dioscorea bulbifera was purchased from local female farmers in Aguata local Government Area of Anambra State. A questionnaire was used to obtain information on the demographic characteristics of the women, as well as their methods of preparing Dioscorea bulbifera. Two processing methods (roasting and boiling) were identified and used in processing of D. bulbifera. The Dioscorea bulbifera tubers were divided into three portions, the first portion was boiled, the second portion was roasted and the third portion was left untreated. All samples were analysed for proximate, minerals, vitamins and antinutrients.  Means were separated using ANOVA. From the result, moisture content (51.87%), crude protein (6.96%), crude fibre (2.82%), and crude lipid (1.28%) were significantly lowered in the boiled and roasted samples (p<0.05). The roasted sample had the highest ash content (2.98%), carbohydrate (83.49%) and energy (364.02 kcal) content (p<0.05). Higher calcium (104.18mg/100g), sodium (122.81mg/100g), potassium (1201.13mg/100g), and  iron (4.91mg/100g) content were obtained from the raw sample, while higher content of magnesium (83.12mg/100g), manganese (6.88mg/100g) and zinc (6.51mg/100g) were recorded in the roasted  sample (p<0.05). The raw sample had the highest content of beta-carotene and vitamin C (301.12 and 2.42mg/100g respectively). The antinutritional levels of the boiled and roasted samples were reduced, but were generally lower in the boiled samples. This study showed that boiling and roasting had both positive and negative effect on Dioscorea bulbifera. The positive effect was derived from the reduction of the anti-nutritional factors, while the negative effect was a reduction in some nutrients found in Dioscorea bulbifera. However, the nutrient content of the yam can be further enhanced by combining with other foods like legumes and pulses in other to improve the nutritional value.