Macronutrients and Micronutrients Profile of Some Underutilized Beans in South Western Nigeria

Beans are a rich source of nutrients in human diet. However a number of edible bean varieties are largely underutilized in developing countries due to little or no information on their nutritional composition. The present study investigated the nutritional content of mung beans, African yam beans, soybeans, black eyed peas and pigeon peas from parts of South Western Nigeria. Samples were collected randomly in duplicates across the six South-western states of Nigeria. Common beans was included as a reference for comparison. Standard methods were used to determine the proximate composition of all bean samples. Mineral nutrients and phaseolin protein fractions (albumin, globulin and prolamine) of bean samples (excluding pigeon pea varieties) was also determined. The proximate, mineral and phaseolin protein contents differed significantly (P<.05) between bean types. Highest protein, fat, carbohydrate, crude fibre and ash content was in African yam bean (24.96%), mung beans (6.60%), soybean (62.81%), mung beans (15.24%) and African yam beans (4.30%), respectively. The beans compared fairly with common beans in proximate composition. Mineral nutrients differed significantly (P<.05) between bean types. Calcium, magnesium, phosphorus and potassium (particularly in Mung beans) were in high amounts. Black eyed peas had the lowest total of mineral content while mung beans had the highest. The phaseolin protein fractions were significantly different (P<.05) among bean types. African yam bean had the highest albumin and globulin content (%/mg protein) of 41.89 and 35.70 respectively, while prolamine was highest in soybeans. These results indicated that these underutilized beans compares favourably in terms of nutritional composition with widely consumed common beans in Nigeria. In addition, African yam beans and Mung beans are equally suitable alternatives from a protein-rich standpoint.