Effect of Malted Mung Bean and Watermelon Rind Flour on Wheat Bread Quality

Abstract

This study was carried out to evaluate the nutrient composition, microbiological, physical and sensory properties of bread produced from wheat, malted mung bean and watermelon rind composite flours. The wheat, mung bean and watermelon rind flours were blended in the ratios of 90:5:5, 80:10:10, 70:15:15, 60:20:20 and 50:25:25, respectively, for the production of bread, while the bread made from 100% wheat flour was used as control. The proximate, mineral, vitamin, microbiological, physical and sensory properties of the bread samples were determined using standard methods. The proximate composition of the bread loaves showed that the samples had a range of 8.11 to 8.61% moisture, 2.18 to 2.69% ash, 3.37 to 4.19% crude fibre, 3.60 to 4.43% fat, 9.18 to 18.42% protein, 61.67 to 73.57% carbohydrate and 350.21 to 363.98 kJ /100g energy. The moisture, ash, crude fibre, fat and protein contents of the samples increased significantly (p< 0.05) with increase in the addition of malted mung bean and watermelon rind flours, while the carbohydrate and energy contents decreased. The mineral composition of the bread loaves were 77.01 to 97.77mg/100g calcium, 48.89 to 114.74mg/100g magnesium, 41.11 to 97.76mg/100g phosphorus, 62.67 to 94.21mg/100g potassium, 2.18 to 2.78mg/100g iron and 1.62 to 2.25mg/100g sodium. The result showed that the mineral contents of the bread loaves produced from composite flours increased with increased substitution of malted mung bean and watermelon rind flours. The thiamine, niacin, riboflavin, vitamin A, ascorbic acid and folic acid contents of the bread samples ranged from 3.36 to 4.57mg/100g, 2.45 to 3.36mg/100g, 3.51 to 4.60mg/100g, 2.23 to 4.27mg/ 100g, 1.55 to 3.22mg/100g and 1.02 to 1.81mg/100g, respectively. These vitamins increased with increased substitution of malted mung bean and watermelon rind flours. The total viable count of the samples ranged between 0.62 to 1.80cfu/g, while the coliform and fungi counts were nil. The physical properties of the bread samples showed that the loaf volume, specific loaf volume, height, and oven spring decreased, while the weight increased (p<0.05) significantly with increased substitution of malted mung bean and watermelon rind flours.  The sensory properties also revealed that the bread loaves produced from 100% wheat flour were most acceptable to the panellists and also differed significantly (p<0.05) in colour, taste, texture and aroma from the composite flour bread samples. However, the composite bread loaves were also acceptable by the judges because they were relatively rated high in all the sensory attributes evaluated. The study, therefore, showed that the addition of malted mung bean and watermelon rind flours to wheat flour at different stated levels in the production of bread samples relatively enhanced the nutritional quality of composite bread loaves compared to the control.