Uganda is one of the major cassava producing countries in the world. Currently, utilization of cassava is limited to semi-processed products through the informal sector. Cassava has technological potential as a raw material for agro-industrial products, such as flours for baked products, animal feeds and starch. The aim of this study was to investigate the chemical composition of five major cassava varieties grown in Nebbi distict (Uganda), to assess their potential as industrial raw materials. Analysis of the chemical composition of local (Nyamatia and Nyarukeca) and improved (NASE 3, NASE 14, and NASE 19) cassava varieties was carried out using standard methods. Results showed significant (p < 0.05) differences between the varieties indicating high levels of starch, calcium, magnesium, cyanonenic glucosides and phytates. The cassava varieties contain low levels of protein, lipids and minerals with respect to recommended daily intake of these nutrients. Moisture contents ranged from 5.43 for Nyamatia to 10.87 for NASE 19; ash from 1.05 for Nyamatia to 2.39 for NASE 14; crude fiber from 1.06 for Nyamatia to 1.18 for NASE 19; crude protein from 0.74 for Nyarukeca to 1.51 for NASE 14; crude lipid from 0.39 for Nyamatia to 0.63 for NASE 19; and starch contents from 66.72 for NASE 19 to 84.42 for NASE 3. The mineral contents (mg/kg): calcium ranged from 13.15 for Nyamatia to 16.56 for NASE 3; iron ranged from 0.002 for Nyarukeca to 0.01 for NASE 19; zinc ranged from 0.56 for Nyamatia to 0.87 for NASE 3; magnesium ranged from 3.58 for NASE 19 to 3.88 for Nyarukeca; and copper ranged from 0.002 for Nyamatia to 0.14 for NASE 3. The contents of anti-nutrients (mg/kg): cyanogenic glucosides ranged from 30 in NASE 3 and NASE 19 to 800 in Nyamatia; phytates ranged from 661.33 in Nyarukeca to 984.64 in NASE 3; oxalates ranged from 90.6 in Nyarukeca to 227.8 in NASE 3; and tannin ranged from 0.18 in Nyarukeca to 0.33 in NASE 3. Based on the chemical composition results, all the cassava varieties studied contain higher levels of cyanogenic glucosides than recommended by Ugandan and East African Standards, making them unsafe for direct utilization as food and food raw materials for industries at levels beyond 30% in food formulations. The high starch levels in all the cassava varieties make them valuable raw materials for starch and starch-related industries.

Textural hardness affects cooking time, processing, fuel used and the quality of cooked bananas. In this study, textural hardness of selected Ugandan cooking and juice banana cultivars at green maturity was determined using a Texture Analyzer in raw form and at 30, 50, 70, 90, 100 and 130 min in boiled, steamed, mashed and cooled forms.Raw juice bananas (JB) were significantly harder (36.17N to 42.43N) than raw cooking bananas (CB) (22.37N to 26.72N) (p&lt;0.05). On cooking, JB were harder than CB irrespective of cooking method and time. Boiling and steaming rapidly decreased hardness of the bananas in the first 30 min and decreased slowly thereafter. Boiling produced softer bananas than steaming while mashing resulted in intermediate hardness. Amongst JB, Kayinja was significantly harder than Ndiizi and Kisubi in boiled and steamed forms (p&lt;0.05). Hardness of CB was not significantly different (p&gt;0.05) for all cooking treatments, but Kibuzi was consistently softer while Kazirakwe and Nakabululu were harder than other CB cultivars.Cooling significantly increased (p&lt;0.05) hardness of bananas under all treatments with JB being harder in all cases. Mashed and steamed bananas were harder than boiled bananas when cooled. Bananas cooked longer had lower hardness regardless of cooking method.Overall, textural hardness decreases with cooking time regardless of cooking method. Boiled bananas are softer than mashed or steamed. Cooling increases hardness which follows first order kinetics. Therefore, bananas should either be boiled or steamed and mashed for softer texture and be eaten within 30 min of serving. Juice bananas should not be cooked because of the hard texture established in this study.

Uganda produces cassava, which has potential as a raw material for agro-industry. In this study, wheat flour was blended with high quality cassava flour in the ratios 100:0, 90:10; 80:20; 70:30; 60:40; 50:50 and 40:60 and the composite dough used to prepare bread. The doughs were subjected to rheological analysis using mixolab, consistograph and alveograph. Bread physical properties were measured and sensory qualities evaluated to correlate rheological characteristics of flour/dough with bread quality. Inclusion of cassava flour in the composite dough negatively affected the quality of the composite bread compared to the control. Bread volume (631.0 to 516.7 cm3) decreased, specific volume (2.065 to 1.574 cm3/g) decreased, bread density (0.49 to 0.63 g/cm3) increased. Mean scores for sensory quality parameters reduced: crust colour (6.88 to 4.63), taste (7.13 to 4.25), crumb texture (6.5 to 4.63) and overall acceptability (8.13 to 4.5). Bread quality was positively correlated with mixolab parameters protein weakening (C2), dough stability and dough development time (DDT); alveograph parameters tenacity (P) and deformation energy (W); and consistograph parameter maximum pressure (PrMax). Results showed that bread of acceptable quality can be processed using wheat composite containing 20 % cassava flour. Rheological properties can be used to assess suitability of flour for bread making.

Samples of three-leaved yam (TLY) tubers were subjected to different boiling times using different concentrations of trona solution. The effects of these conditions on the proximate composition and physico-chemical properties were analyzed. The fat and fibre contents were not affected by changes in trona concentration and boiling time. The moisture and ash content increased with increase in trona concentration and boiling time while protein showed a decreasing trend: The values for swelling index, water absorption capacity, blue value index and total soluble solids showed significant increases (P ≥ 0.05) with increase in trona concentration and boiling time.

Texture is an important quality attribute of fresh and processed foods. In plant foods, texture is closely related with the structural integrity of the primary cell walls and middle lamella that is mainly composed of pectic substances. Bananas mainly contain water, starch, pectin and fibre which influence texture. Cooking bananas soften on cooking but harden on cooling. Despite many studies on retrogradation of starch and its effects on texture, little is known about the effect of added starch and/or breakdown of pectin on hardness of bananas upon cooking and cooling. In this study, the effects of added pectin and starch and structural elimination of pectin on hardness of bananas during cooking and cooling were investigated. Hydrolysis of pectin resulted in significantly harder bananas during cooking and upon cooling (P&lt;0.05). Hardness of starch-treated bananas increased significantly with increasing starch concentration upon cooking and cooling relative to the control (P&lt;0.05). However, treatment of bananas with added pectin alone resulted in an insignificant increase in hardness relative to the control. Upon cooling, hardness of pectin-treated bananas decreased significantly with increasing pectin concentration (P&lt;0.05). Hardness of cooked bananas treated with a combination of starch and pectin increased but was not significantly different from the control. Upon cooling, hardness of the starch-pectin treated bananas decreased with increasing concentration similar to the effect of pectin when added alone. Current results showed that starch addition increases hardness of bananas upon cooking and cooling. However, pectin addition decreases hardness of cooked bananas upon cooling while structural elimination of pectin increases hardness upon cooking and cooling. These results imply that pectin contributes to a softer texture of bananas during cooking and cooling whereas starch increases hardness in cooked bananas. Pectin can therefore be added up to 5% to decrease hardness of cooked bananas.