Browsing by Author "Mongi, R. J."

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    Descriptive sensory analysis, consumer acceptability, and conjoint analysis of beef sausages prepared from a pigeon pea protein binder
    (Cell Press, 2022) Mongi, R. J.; Gomezulu, A. D.
    The objective of this study was to assess the sensory profile, consumer acceptance, and internal and extrinsic factors influencing the acceptability of beef sausages made at varying levels of pigeon pea protein (2, 4, and 6% w/w) as a binder. Sausages prepared without binders (CNB) and sausages made with a chemical phosphate binder served as controls (PoB). A panel of 12 trained panelists performed descriptive analysis using the quantitative descriptive analysis (QDA) approach on a 9-point line scale, while 70 consumers participated in a consumer test utilizing a 9-point hedonic scale. Preference mapping was done by linking descriptive sensory and hedonic data using partial least squares regression analysis (PLSR) and the conjoint analysis was conducted by 90 panelists using a 9-point scale. The 6% pea protein sausages had the significantly lowest (p < 0.05) mean hardness, aroma, and color intensity but statistically similar (p > 0.05) highest moistness intensity to the phosphate sausages. Phosphate sausages had the highest mean color and saltiness intensity (p < 0.05) compared to the lowest mean values in 6% pea protein sausages. The phosphate sausages were the most accepted by consumers (p < 0.05), followed by the 6% pea protein sausages, with aroma, saltiness, moistness, and firmness being the key drivers in consumer acceptability of sausages. Furthermore, formulation and price had a significant (p < 0.05) effect on consumer acceptability. In conclusion, employing pea protein as a binder in sausage formulations improves sensory profiles and increases consumer acceptance, making it a possible food industry alternative. Further studies to determine the optimal amount of pea protein binder that will perform better than phosphate binder are recommended.
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    Development and assessment of frying characteristics, chemical composition, descriptive sensory properties and preference mapping of wheat-orange fleshed sweet potato composite Swahili buns (Maandazi)
    (Sokoine University of Agriculture, 2015) Mongi, R. J.; Simbano, M.; Ruhembe, C.; Majaliwa, N.
    This study was carried out to investigate frying characteristics, chemical composition and sensory evaluation of whole-wheat buns (WWB) and Wheat-Orange fleshed sweet potatoes - composite buns (WPCB) at different levels of wheat flour substitutions. A whole-wheat buns (WWB) and OFSP-composite buns (WPCB 1, WPCB 2 and WPCB 3) were prepared in triplicate at 0, 10, 20 and 30% levels of wheat flour substitution respectively, and evaluated for weight, volume, specific volume, proximate composition, vitamin A, descriptive sensory profile, consumer liking and preference mapping. Completely randomized design was used to assess and compare frying characteristics, proximate and vitamin A contents between samples with bread types being the principal factor while Randomised complete Block design was used to assess sensory properties and consumer acceptability of the bread samples with panelists and bread types being the principal factors. The results showed that moisture content, crude fibre, and ash contents of the composite buns increased significantly (p<0.05) while the carbohydrate, crude fat and protein contents decreased significantly (p<0.05) with progressive increase in the OFSP flour. The WPCB3 had significantly (p<0.05) highest moisture, ash and fibre values of 17.13, 2.97 and 1.31 g/100g DM, respectively, compared to lowest values of 14.05, 2.17 and 0.48 g/100 g DM, respectively in WWB. However, significantly (p<0.05) higher fat, carbohydrate and protein values of 1.95, 70.68 and 8.06 g/100g DM compared to lowest values of 0.89, 54.13 and 6.56 g/100 g DM, respectively was observed in WPCB 3. Vitamin A content increased significantly (p<0.05) as OFSP flour increased with the highest value of 700 μg/100 g RE DM in WPCB3 and smallest value of 170 μg/100g RE DM in WWB. The mean intensity values of all sensory attributes between samples differed significantly as a wheat flour substitution increased except for taste and aroma between WWB and WPCB 1 which had statistically (p>0.05) similar mean intensity scores in taste, aroma, and texture acceptability as WWB. Similarly, consumers showed statistically similar scores in acceptability between WWB and WPCB 1. The Preference mapping results showed colour and taste were the main drivers for consumer preference. In conclusion, the study shows that the use of OFSP flour up to 10% of the flour into wheat flour produced nutrient enhance buns with similar and acceptable taste, texture, mouth feel and aroma comparable to 100% wheat buns.
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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 and mineral composition of cocoyam (Colocasia esculenta L. and Xanthosoma sagittifolium L.) grown along the Lake Victoria basin in Tanzania and Uganda
    (Academic Journals, 2011) Ndabikunze, B. K.; Talwana, H. A. L.; Mongi, R. J.; Issa-Zacharia, A.; Serem, A. K.; Palapala, V.; Nandi, J. O. M.
    The proximate and mineral compositions of cocoyam (Colossian esculenta L. and Xanthosoma sagittifolium L.) grown along Lake Victoria Basin in Tanzania and Uganda were analyzed. C. esculenta and X. sagittifolium samples were significantly (p < 0.05) different in terms of their proximate composition and mineral contents regardless of their country of origin. Proximate analyses included ash, crude protein, and crude fibre. Proximate composition of cocoyam results demonstrated that X. sagittifolium variety is nutritionally superior to that of C. esculenta. Minor nutrients measured were calcium, magnesium, copper, iron, sodium, zinc, manganese, and potassium. The results from these analyses demonstrate that the proximate composition of cocoyam produced in Uganda is substantially different from that produced in Kenya, regardless of the variety. Information obtained from this study can be used to develop cocoyam based food products with enhanced nutrition and potential to promote commercial scale production and utilization of cocoyam in East African countries.
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    Proximate composition, bread characteristics and sensory evaluation of cocoyam-wheat composite breads.
    (Rural Outreach Program, 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.