Evaluation of wheat-sorghum-chickpea composite bread for physical, nutritional and sensory quality

Abstract

The incorporation of whole chickpea (Kabuli) flour into sorghum (Sorghum bicolor L. Moench) wheat composite flour could improve nutritional quality of wheat (Triticum aestivum L.) bread. The aim of the study was to produce bread using sorghum genotype EUS130 and chickpea, compare physical and baking properties, nutrient levels, in vitro protein digestibility, shelf life and sensory acceptability. Randomized Complete Block Design was used to compare different breads. Sorghum-wheat composite bread was prepared in proportions wheat: sorghum; 100:0 (control), 96:4, 92:8, 88:12and 84:16. Results showed that specific loaf volume (SLV) was low in composite loaves, protein content was highest (p<0.05) in 8% sorghum bread, ash and fibre were high in composite loaves compared to control. The shelf life were also higher in sorghum composite bread (9 days) than control (6.3 days) while in vitro protein digestibility was not significantly (p>0.05) different among the loaves. Sorghum composite flour was further enriched with chickpea in proportions wheat: sorghum: chickpea was 100:0:0 (control), 96:0:4, 92:0:8, 88:0:12 and 84:0:16 (0%). Sorghum 4% bread blended in proportion 92:4:4, 88:4:8, 84:4:12 and 80:4:16 (4%); 8% bread proportion 88:8:4, 84:8:8, 80:8:12 and 76:8:16 (8%). The 12% bread proportion 84:12:4, 80:12:8, 76:12:12 and 72:12:16 (12%) while 16% was mixed in proportion of 80:16:4, 76:16:8, 72:16:12 and 68:16:16 (16%). The composite bread had similar dough length, height, area under curve and energy (W) with control, values decreased with increase in wheat substitution. Fibre, oil and protein contents were significantly (p<0.05) high in chickpea enriched bread compared to control, values increased with increase in wheat substitution. Carbohydrate content was low (p<0.05) in enriched bread, values decreased with increase in substitution level. In addition, the In vitro protein digestibility was low (p<0.05) in wheat-sorghum-chickpea. Sensory scores; texture, taste, chewiness and general acceptability were highly rated in control and bread from 92% wheat:4% sorghum:4% chickpea proportion. Microbial counts (cfu/g) were lowest (p<0.05) in 12% chickpea enriched sorghum bread while shelf life was significantly (p<0.05) high in sorghum and chickpea containing bread compared to control. In conclusion, bread from proportion 92% wheat:4% sorghum:4% chickpea was most acceptable. It is recommended that, as a policy in Kenya, this composite flour be used for production of bread and other confectionaries to further improve nutritional and sensory quality of wheat based products.