Effect of Different Processing Methods on the Nutritional Value of Red and White Bean Cultivars (<i>Phaseolus vulgaris </i>L.)

Abstract

Among legumes, common bean plays significant role in the diet of Cameroonians. It is a good source of protein, fiber and micronutrients. However, bean contains substantial amount of antinutrients, which limit their utilization. This work evaluates the effect of different processing methods on the macronutrients, micronutrients and antinutrients contents in two bean cultivars (<i>Phaseolus vulgaris </i>L.). A survey was done in the city of Yaounde on the different processes applied on the cultivar before cooking. From the results of the survey, beans treatment were divided into six groups: raw, boiled, boiled with sodium bicarbonate, boiled with <i>Echinops giganteus</i> bark powder, soaked and boiled, soaked with sodium bicarbonate and boiled. The processed samples were analyzed for proximate and antinutrients composition using AOAC methods and minerals by atomic absorption spectrophotometry. The raw seed served as the control. The results of this study have shown that processing led to an increase significantly (p<0.05) in protein contents. The higher rate of protein were observed for soaked and boiled (25.82%) and boiled (24.23%) respectively for white and red bean. The fiber contents of soaked with sodium bicarbonate and boiled white bean were higher (8.39%) compare to fiber content values recorded for red bean cultivars samples. Fat contents are significantly (p<0.05) lower with all samples after processing. The carbohydrate content of the boiled with <i>Echinops giganteus </i>bark powder of red bean was the highest (59.26%) followed by boiled with sodium bicarbonate red bean 58.61%. Boiled with <i>Echinops giganteus</i> bark powder white bean cultivar had higher iron, zinc, potassium and magnesium while boiled red and white bean cultivar had higher copper levels. Soaked and boiled white bean cultivar had higher calcium while boiled with sodium bicarbonate red bean had higher sodium levels. Processing improved significantly (p<0.05) the nutritional value of the beans by reducing the antinutrient contents. Soaking with sodium bicarbonate and boiling were found to have the highest level of reduction effect on the tannin, oxalate and saponin particularly in the white bean cultivar. Red and white bean cultivars could be used as a food formulation material for infants and young children to prevent protein energy malnutrition.