Effect of dehulling/soaking on the chemical, functional and anti‐nutritional contents of three varieties of beans

Abstract

PurposeThe purpose of this paper is to evaluate the effect of dehulling/soaking on the chemical, functional and anti‐nutritional contents of three varieties of beans. This research work involved comparative study of the underutilized bean species with the commonly consumed beans in Nigeria.Design/methodology/approachThree species of legumes were used for this study. The cowpea seeds were divided into two parts. One part was milled and packaged for raw flour while the other part was dehulled and soaked for 30 min, dried in the oven, milled and packed. For the pigeon pea and African yam beans, the raw beans were milled and packaged while part of the seeds was steamed for 5 min and the coats were removed. The dehulled beans were soaked for 30 min, dried in the oven, milled and packaged. Chemical, functional and anti‐nutritional content were determined on the samples.FindingsFat content ranged from 0.95 to 1.98 per cent. Ash and crude fibre ranged from 1.98 to 6.13 and 2.41 to 7.90 per cent, respectively. Raw cowpea had the highest calcium content (3.86 per cent) while pigeon pea had higher value in magnesium content (2.01 per cent). Raw African yam beans had the highest iron content (23.44 per cent). Bulk density, swelling index and water‐absorption capacity ranged from 0.53 to 0.92 g/cm3, 2.3 to 5.9 and 0.9 to 2.8 ml H2O/g, respectively. African yam bean had higher values in oxalate, phytate and tannin contents while cowpea had higher saponin content. Raw flour of pigeon pea had higher value in trypsin inhibitor.Originality/valueThis work enables us to make use of the underutilized beans. These beans were higher in nutrients than the cowpea used. Processing of these beans will make them useful for human nutrition without imposing any health problem to the consumer. They could also be converted to flour and used in formulating food such as weaning food.