Effects of banana peel-ash-extract on cooking time and acceptability of hard-to-cook beans (<i>Phaseolus vulgaris</i> l.)

Abstract

Beans are among the most important crops that contribute substantially to the agricultural sector and household food security in Uganda. Kawanda (K) 132 (Nambale) is presently a major bean (Phaseolus vulgaris L.) variety of high nutritional value. However, the hard-to-cook (HTC) defect limits its utilization, requiring appropriate processing to preserve the nutrients. Banana peel ash-extract, widely used in indigenous processing of dry beans, was evaluated for chemical composition and potential in reducing cooking time of beans with HTC defect. The peel ash-extract was found to contain substantial amounts of sodium (0.36 g/ml), chloride (0.07 g/ml) and magnesium (0.04g/ml) ions. Calcium, iron, copper, zinc, sodium and phosphorus were also found in detectable amounts. Generally, addition of the peel-ash-extract was found to reduce the cooking time of K132 beans. The cooking time of K132 beans, processed in ash-extract (0.31 g/ml), reduced by 52.3%. Reduction in cooking time was also found to correlate strongly (R2=0.89) with the pH of the ash-solution. Processing of K132 beans in ash-solution of pH G 11 reduced the cooking time by nearly 50%. Sensory attributes of dry beans cooked in banana peel ash-extract were preferred to that cooked in ordinary water. Beans cooked in peel ash-extract at a concentration of 0.23 g/ml were the most preferred (5.81±0.59) to that boiled in ordinary water (4.71±0.26). The taste, flavor and acceptance scores were, in general, higher in beans processed in ash-extract than that of ordinary water. The appearance, consistency and texture of cooked beans were not significantly different (p