Browsing by Author "Mongi, R. J."

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    Effect of cooking on tannin and phytate content in different bean (Phaseolus vulgaris) varieties grown in Tanzania
    (Academic Journals, 2017) Mamiro, P. S.; Mwanri, A. W.; Mongi, R. J.; Chivaghula, T. J.; Nyagaya, M.; Ntwenya, J.
    Phytates and tannins are present in varying proportions in legume based foods. Investigation on the effect of cooking on tannins and phytates was carried out on thirty eight raw and cooked bean (Phaseolus vulgaris) varieties. Tannins were assayed by vanillin-hydrochloric acid method, while phytates were determined by a method developed by Haugh and Lantzsch. There was a very high significant difference (P≤0.00001) in the tannin concentrations between the raw and cooked bean samples. The mean tannin content for the raw and cooked samples was 1.168±0.81 and 0.563±0.503%CE, respectively. Reduction of tannins after cooking ranged from 20%CE in M’mafutala to 81%CE in GLP 2 with an average reduction of 56.3%CE. Equally, there was a very high significant difference (P≤0.0001) in the phytate concentrations between the raw and cooked bean samples. The mean phytate content for the raw and cooked samples were 0.0219±002 and 0.0122±003 μg/mL, respectively. Cooking reduced the anti-nutritional factors significantly (p≤0.0001). The extent of antinutritional factors reduction varied between bean varieties. Cooking is therefore important for mineral absorption during digestion process in humans as it makes the minerals less bound and hence physiologically available.
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    Proximate composition, bread characteristics and sensory evaluation of Cocoyam-Wheat composite breads
    (Ajfand, 2011) Mongi, R. J.; Ndabikunze, B. K.; Chove, B. E.; Mamiro, P.; Ruhembe, C. C.; Ntwenya, J. G.
    This study was carried out to investigate proximate composition, bread characteristics and sensory evaluation of cocoyam-wheat composite breads at different levels of cocoyam flour substitution for human consumption.A whole wheat bread (WWB) and cocoyam-composite breads (CCB1,CCB 2 and CCB 3) were prepared in triplicate at 0, 10, 20 and 30% levels of cocoyam flours substitution respectively and assessed for proximatecomposition, bread characteristics and sensory attributes.The results indicate that carbohydrate, crude fiber, and ash contents of the cocoyam-composite breads increased significantly (p<0.05) while the moisture and protein contents decreased significantly with progressive increase in the cocoyam flour substitution. The significant (p<0.05) highest ash, fibre and carbohydrate values of 1.61, 1.54 and 70.40 g/100g dm respectively were observed in 30% cocoyam-wheat composite bread compared to lowest values of1.15, 0.29 and 63.25 g/100g dm, respectively in 100% wheat bread. The significant (p<0.05) higher moisture and protein values of 20.99 and 12.54 g/100g dm were observed in 100% wheat bread compared to lowest values of 17.31 and 9.04 g/100g dm, respectively in 30% cocoyam-wheat composite bread. Bread characteristics showed that, the loaf weight of cocoyam composite breads increased significantly (p<0.05) while loaf volume and specific loaf volume decreased significantly (p<0.05) with increasing cocoyam flour substitution The significant (p<0.05) highest loaf weight of 229.33 g was observed in 30% cocoyam-wheat composite bread compared to 208.33, 221.67 and 225 g observed in 100% wheat bread, 10 and 20% cocoyam-wheat composite breads respectively. The highest loaf volume and specific loaf volume of 800 and 3.49 cc were observed in 100% wheat bread compared lowest values of 580 and 2.78 cc respectively observed in 30% cocoyam-wheat composite bread. The sensory evaluation showed no significant (p>0.05) differences in sensory attributes of taste, aroma and acceptability between the 100% wheat and 10% cocoyam-wheat composite breads (p<0.05). In conclusion, this study has shown that the use of cocoyam flour in bread making is feasible and that incorporation of up to 10% of the flour into wheat flour produced acceptable bread with similar taste and aroma comparable to 100% wheat bread. Nevertheless, it is important to consume this bread with other protein rich diet in order to supplement the reduction resulted from substitution.