Effect of Different Cooking Methods on Proximate, Vitamins, Minerals and Antinutrients Composition of African Yam Bean (Sphenostylis stenocarpa) Seeds

Abstract

Background: Food researchers are constantly looking for easier and faster methods to ensure optimum nutrient intake. Objectives: The study investigated the effect of cooking methods (boiling and toasting) on the chemical composition of African yam beans (AYB). Methodology: Flecked-brown African yam beans were divided into three portions, the first two portions were toasted and soaked boiled, the third was left raw to serve as control. The samples were evaluated for proximate, nutrients, and antinutrient composition using standard procedures. Data collected was analyzed with IBM Statistical Product for Service Solution (SPSS) software version 21 and presented with descriptive statistics (frequencies, percentages, means, standard deviation). Analysis of variance and Duncan multiple range test were used to compare and separate the means. Results: Toasting had 0.59%, 0.53%, 0.15%, and 0.11% reductions in moisture, crude protein, fat, and crude fiber content of AYB; and 0.15%, 1.23%, and 1.45Kcal increase in ash, carbohydrate, and energy respectively. Soaked boiling reduced all the proximate contents of AYB but had 2.05% increase in moisture. Toasting had no significant effect on AYB beta-carotene but had 0.04mg, 0.02mg, 0.11mg, and 1.59mg reductions on thiamin, riboflavin, niacin, and vitamin C contents respectively. Soaked boiling reduced the content of all the vitamins studied by 6.15µg, 0.09mg, 0.03mg, 0.22mg, and 3.11mg respectively. Toasting reduced AYB zinc (0.02%), and sodium (0.16%) contents but increased calcium (8.04%), magnesium (1.73%), iron (0.05%) and potassium (3.46%), while soaked boiling had significant reductions (0.21mg, 10.68mg, 3.87mg, 3.64mg, 1.42mg, and 296.54mg) in zinc, calcium, magnesium, sodium, iron, and potassium contents of AYB respectively. Toasting and soaked-boiling significantly reduced saponin, tannin, alkaloids, flavonoids, and phytate by 0.08mg, 0.3mg, 0.6mg, 0.12mg, 0.15mg; and 0.14mg, 0.09mg, 0.18mg, 0.26mg, 0.25mg respectively. Conclusion: Toasting and soaked boiling had significant effects on the chemical composition of AYB