Effects of processing methods on nutritive values of Ekuru from two cultivars of beans (Vigna unguiculata and Vigna angustifoliata)

Abstract

Beans contain substantial amount of protein, dietary fibre, B-vitamins, minerals, and anti-nutrients which limit their utilisation. Processing reduce the level of antinutrients in plant products but little information exist on effects of processing methods on nutrient and antinutrient composition of bean products. This study was undertaken to determine the effects of processing methods on nutrient and antinutrient composition, and micronutrient potential of bean paste (Ekuru) from two cultivars of beans, white (Vigna unguiculata) and red (Vigna angustifoliata) species of beans which were processed into white and brown Ekuru using standardised traditional methods. 100 g of raw V. unguiculata and V. angustifoliata contained 22.83 and 23.94 g protein, 1.94 and 2.11 g crude lipid, 30 and 29 mg sodium, 1.110 and 1.124 mg potassium, 390 and 130 mg phosphorus, 10.65 and 10.95 mg iron and 5.87 and 5.95 mg zinc, respectively. Ekuru products contained between 18.76 and 21.90 g protein, 0.81 and 1.38 g crude lipid, 20.00 and 90.00 mg sodium, 870 and 1124 mg potassium, 8.16 and 8.36 mg iron and 4.87 and 5.21 mg zinc, respectively. Processing decreased the nutrient content of the products compared with raw samples, the red bean product was higher in crude protein, crude lipid and ash; while the white bean product was higher in crude fibre and moisture content. The bean products were very low in antinutrients, with no trypsin inhibitors. Ekuru samples can be good sources of plant protein, nonhaeme iron and zinc, and their consumption should be encouraged.

Key words: Processing methods, nutritive value, antinutrients, Ekuru, Vigna unguiculata, Vigna angustifoliata.