Browsing by Author "Onyango Calvin"
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Publication Batter rheology and bread texture of sorghum‐based gluten‐free formulations modified with native or pregelatinised cassava starch and α‐amylase(Institute of food Science technology, 2010-05-26) Onyango Calvin; Mutungi Christopher; Ubehend Gunter; Lindhauer Meinolf G.Summary The influence of a-amylase (0–0.3 U g)1) on the crumb properties of gluten-free sorghum batter and bread, respectively, was investigated. The formulations were modified using native or pregelatinised cassava starch (i.e. batter A – 17% pregelatinised starch, 83% sorghum, 100% water fwb; batter B – 17% native starch, 83% sorghum, 100% water fwb; and batter C – 30% native starch, 70% sorghum, 80% water fwb). The batters had solid viscoelastic character with the storage modulus predominant over the loss modulus. Storage moduli of batter A decreased with increasing angular frequency, whereas the moduli of batters B and C were independent from the angular frequency. Increasing enzyme concentration did not affect the loss factors of the batters. Batters’ resistance to deformation, from highest to lowest, followed the order C > A > B. Increasing enzyme concentration decreased crumb firmness, cohesiveness, springiness, resilience and chewiness but increased adhesiveness. Overall, breads containing native starch had better crumb properties (i.e. springier and less firm, chewy and adhesive) than breads containing pregelatinised starch.Publication Creep-Recovery Parameters of Gluten-Free Batter and Crumb Properties of Bread Prepared from Pregelatinised Cassava Starch, Sorghum and Selected Proteins(International Journal of Food Science & Technology, 2009) Onyango Calvin; Muttungi Christopher; Unbehend Gunter; Lindhauer G. MeinolfThe effect of egg white, skim milk powder, soy protein isolate and soy protein concentrate on creep-recovery parameters of gluten-free batter made from sorghum and pregelatinised cassava starch was studied. Batter treated with egg white had the highest deformation and compliance parameters and lowest zero shear viscosities and differed significantly (P < 0.05) from the other treatments. However, this batter recovered its elasticity sufficiently and its elastic portion of maximum creep compliance did not differ significantly (P < 0.05) from the other treatments. Unlike the other treatments, egg white did not decrease bread volume and exhibited the lowest crumb firmness and staling rate. Optimisation of the amount of egg white with diacetyl tartaric acid esters of mono and diglycerides (DATEM) showed that creep-recovery parameters and crumb hardness were affected by the linear, quadratic and interaction effects of the input variables. Treatment with 6% and 0.1% w ⁄ w fwb egg white and DATEM, respectively, gave gluten-free batter with the least elastic portion of maximum creep compliance (Je ⁄ Jmax = 11.65%) which corresponded to the lowest crumb firmness (790.8 g).Publication Determination of Optimum Conditions for Enzymatic Debranching of Cassava Starch and Synthesis of Resistant Starch Type III using Central Composite Rotatable Design(WILEY ONLINE LIBRARY, 2009-07-13) Christopher Mutungi; Onyango Calvin; Jaros Doris; Henle Thomas; Rohm HaraldCassava starch was debranched by treatment with isoamylase and pullulanase and the yield of resistant starch type III (RS III) optimized with respect to starch solids concentration (7.5-15%, w/v), incubation time (8-24 h) and enzyme concentration using central composite rotatable design. Higher concentrations of pullulanase (10-35 U/g starch) compared to isoamylase (30–90 mU/g starch) were required to give a similar degree of starch hydrolysis within the experimental domain. A clear debranching end-point was identifiable by following the reducing value, blue value and β-hydrolysis limit of cassava starches debranched using isoamylase. It was difficult to define a debranching endpoint of pullulanase treatment by these parameters due to contaminating α-D-(1→4) activity. The yield of RS III was significantly higher in isoamylolysates and increased steadily with increasing degree of hydrolysis to peak at 57.3%. Purification of the debranched material further increased the RS III yield to 64.1%. Prolonged (24 h) hydrolysis of cassava starch with high concentration of pullulanase (35 U/g) gave lower RS III contents in the purified (34.2%) and unpurified (36.2%) hydrolysates compared to 49.5 and 62.4%, respectively, at moderate pullulanase concentration (22.5 U/g) and incubation time (16 h).Publication Digestibility and Antinutrient Properties of Acidified and Extruded Maize–Finger Millet Blend in the Production of Uji(ScienceDirect, 2004) Onyango Calvin; Noetzold Horst; Ziems Annette; Hofmann Thea; Bley Thomas; Henle ThomasLactic and citric acids were used as alternatives to backslop fermentation in the manufacture of extruded uji (a thin porridge from eastern Africa). Acidity of the blends was reduced by fermentation or progressively lowered with 0.1, 0.5 and 1.0 mol/l lactic or citric acids before extrusion. The absence of ethanol soluble starch in the extrudates indicated that extrusion solubilizes starch without formation of maltodextrins. In vitro starch digestibility increased from 20 mg maltose/g starch in the raw blend to about 200 mg/g after extrusion. Extrusion reduced total dietary fibre by 39–68%, redistributed soluble to insoluble fibre ratios and had a negligible effect on the formation of resistant starch (less than 1 g/100 g). In vitro protein digestibility increased after fermentation or acid treatment followed by extrusion. Nitrogen solubility index decreased by 40–50% when the unfermented, lactic or citric acid treated blends were extruded, but increased by 20% when the blend was fermented before extrusion. Amino acid analysis showed that histidine, lysine and arginine contents were lowest in the fermented-extruded blends. Tannin content decreased from 1677 mg/100 g in the raw blend to between 551 and 1093 mg/100 g in the extrudates whereas phytate content remained unaffected by extrusion (248–286 )Publication Effect Of Cellulose-Derivatives and Emulsifiers on Creep-Recovery and Crumb Properties of Gluten-Free Bread Prepared from Sorghum and Gelatinised Cassava Starch(Food Research International, 2009) Onyango Calvin; Ubehend Gunter; Lindhauer G. MeinolfThe effect of cellulose-derivatives and emulsifiers on the creep-recovery behaviour of glutenfree dough prepared from gelatinised cassava starch and sorghum was studied. Cellulose treated doughs, except the treatment with 2.4% w/w fwb CMC, had lower resistances to deformation (range 10–33%) than emulsifier-treated doughs (range 3–13%). The higher elastic recovery of emulsifier-treated doughs corresponded to lower compliances and higher zero shear viscosities than for doughs treated with cellulose-derivatives. Addition of egg white powder (6.7% w/w fwb) eliminated several textural defects associated with gluten-free bread. Cellulose-derivatives did not decrease crumb firmness or staling rate when compared to the control. Though increasing emulsifier concentration (from 0.4% to 2.4% w/w fwb) decreased crumb firmness, crumbs treated with 2.4% w/w fwb emulsifiers, except diacetyl tartaric acid esters of mono- and diglycerides, were weak and difficult to handle after slicing. Nevertheless, all gluten-free breads treated with 2.4% w/w fwb emulsifiers staled at a slower rate than the control.Publication Effect of Extrusion Variables on Fermented Maize–Finger Millet Blend in the Production Of Uji(ScienceDirect, 2004) Onyango Calvin; Henle Thomas; Ziems Anette; Thea Hofmann; Thomas BleyThe effects of screw speed, feed moisture, glucose, fructose, sucrose and maltose on extrusion of lactic fermented and dried maize–finger millet blend was investigated. Fermentation caused a reduction in sectional expansion index, flour bulk density and water absorption index (WAI) but increased specific volume, water solubility index and darkened the extrudates. Increase in feed moisture (13–25%) reduced sectional expansion index, specific volume and yellowness but increased extrudate moisture content, bulk density and darkness of the extrudates. Increasing screw speed (158–242 rpm) had a negative correlation only with specific volume and lightness (P<0.05). An increase in the content of any of the sugars reduced extrudate moisture content, sectional expansion index, WAI and specific volume but increased bulk density and water solubility index. Extrudates treated with monosaccharides were darker than extrudates treated with disaccharides.Publication Flavour Compounds in Backslop Fermented Uji (An East African Sour Porridge)(ResearchGate, 2000-12) Onyango Calvin; Heike Raddatz; Bley ThomasThe potential of Lactobacillus plantarum, Pediococcus acidilactici, Pediococcus pentocaceus, Lactobacillus cellobiosus, different mixtures of these lactic acid bacteria and backslop starter cultures to acidify and form flavour compounds in uji was investigated. The bacteria chosen are the most prevalent species in fermented uji. Flavour compounds were analysed using GC-MS and GC-FID with HP5 non-polar column and DB-Wax polar columns respectively. Use of pure single or mixed cultures did not improve the flavour profile of fermented uji. On the basis of peak areas of unfermented and fermented uji aromagrams, pentanal, hexanal and hexadecanoic, 9,12-octadecadienoic, oleic and octadecanoic acids were found to be native to the flours, while 3-methyl-1-butanol, octanoate, nonanoate, hexadecanoate, linoleate, oleate and hexanoic, heptanoic, octanoic and nonanoic acids were synthesised during submerged culture fermentation. Ethanol, 1-pentanol, 1-hexanol, lactic acid and ethylacetate were synthesised prior to fermentation and synthesis of these compounds continued during fermentation.Publication Impact of Carrageenan Copolymers from Two Red Seaweed Varieties on Dough and Bread Quality(JOURNAL OF APPLIED PSYCHOLOGY, 2021) Onyango Calvin; Luvita K.S; Lagat Kibet; Kosambo LinusAbstract The impact of cottonii (COT, Kappaphycus alvarezii) and spinosum (SPI, Eucheuma denticulatum) flour (1–10% w/w) on rheological properties of wheat (WHE) and quality of bread was investigated. Wheat-COT and WHE-SPI had higher water absorption capacities, dough development times, dough stabilities and farinograph quality numbers than WHE dough. Extensograms of composite dough were largely similar to those of WHE at the same incubation times. Dough energy decreased whereas elasticity ratio (ratio of maximum resistance to extensibility) increased when incubation time was increased from 45 to 135 min. Wheat-COT and WHE-SPI had lower pasting temperatures but higher peak, final, breakdown and setback viscosities than WHE flour. Specific volume of bread containing COT (5% w/w) or SPI (7.5% w/w) was not different (p > 0.05) from that of WHE bread. Crumb texture properties of these composite breads were also largely similar to those of WHE bread. The physical properties of WHE dough and bread were influenced by gluten, whereas those of WHE-COT and WHE-SPI were influenced by gluten in addition to κ-carrageenan in COT and ι-carrageenan in SPI. Protein, ash and dietary fibre contents increased (p < 0.05) whereas carbohydrate content of bread decreased (p < 0.05) when WHE was replaced with COT or SPI (5% w/w).Publication Influence of Incubation Temperature and Time on Resistant Starch Type III Formation From Autoclaved and Acid-Hydrolysed Cassava Starch(SciencDirect, 2006-11-24) Onyango Calvin; Bley Thomas; Annette Jacob; Henle Thomas; Rohm HaraldRaw cassava starch, having 74.94 and 0.44 g/100 g resistant starch type II and III (RS II and RS III), respectively, was autoclaved at 121 °C in water, 1, 10 or 100 mmol/L lactic acid. The formation of RS III was evaluated in relation to variable incubation temperature (−20 to 100 °C), incubation time (6–48 h) and autoclaving time (15–90 min). Negligible to low quantities of RS III (0.59–2.42 g/100 g) were formed from autoclaved starch suspended in 100 mmol/L lactic acid, whereas intermediate to high quantities (2.68–9.97 g/100 g) were formed from autoclaved starch suspended in water, 1 or 10 mmol/L lactic acid, except for treatments with water or 10 mmol/L lactic acid incubated at 100 °C for 6 h (1.74 g/100 g). Autoclaving times corresponding to maximum RS III contents were 15 and 45 min for water and 10 mmol/L lactic acid, respectively. Whereas, the RS III fractions from cassava starch suspended in water had melt transitions between 158 and 175 °C with low endothermic enthalpies (0.2–1.6 J/g), the thermal transitions of the acidtreated samples were indistinct.Publication Nutritional Composition, Physical Qualities and Sensory Evaluation of Wheat Bread Supplemented with Oyster Mushroom(Academic Journals Inc., 2015) Ndung’u Stella W.; Otieno Christina A.; Onyango Calvin; Musieba FredrickThe aim of this study was to evaluate nutritional, physical and sensory qualities of wheat-mushroom bread. Dried Pleurotus ostreatus mushrooms were processed into flour and mixed with wheat flour at 0, 5, 10 and 15% to develop bread. Moisture content, crude protein, crude fibre, fat, ash, minerals, amino acids and B-vitamins contents of wheat and wheat-mushroom breads were evaluated. Physical and sensory qualities of wheat and composite breads were also evaluated to determine consumer acceptability. Composite bread with 15% mushroom did not develop as the dough for this ratio did not form a visco-elastic dough. Moisture, total ash and protein contents of the composite breads increased with increasing mushroom content in the bread. Composite bread supplemented with 10% mushroom flour had highest moisture, protein and total ash contents. Carbohydrates content declined while fiber and fat contents did not change. Mineral composition of the composite breads increased with increasing mushroom supplementation except for magnesium, manganese and calcium contents. The contents of all amino acids and B-vitamins analyzed increased with addition of mushroom in bread. Sensory and physical qualities of bread declined with increasing amount of mushroom flour in composite bread. In conclusion, supplementing mushrooms in wheat bread increased protein, minerals, B-vitamins, amino acids contents of wheat-mushroom bread compared to wheat bread. Supplementing wheat flour with up to 10% mushroom flour produced baked products with high nutritional quality for improved health.Publication Production of High Energy Density Fermented Uji using a Commercial Alpha-Amylase orby Single-Screw Extrusion(ScienceDirect, 2003) Onyango Calvin; Henle Thomas; Hofmann Thea; Bley ThomasThe effects of alpha-amylase and extrusion on the viscosity and energy density of uji, a spontaneously fermented thin porridge from different combinations of maize, finger millet, sorghum and cassava, were investigated. Fermentation alone was not able to reduce the viscosity of uji, but addition of 0.1–2.1 ml/100 ml alpha-amylase to the fermented slurry or extrusion of the fermented and dried flour at 150–180°C and a screw speed of 200 rpm reduced the viscosity of 20 g/100 ml uji from 6000–7000 to 1000–2000 cP, measured at 40°C and a shear rate of 50 s−1. The amount of flour required to make uji could thus be increased by a factor of 2.0–2.5 and consequently it was possible to produce uji with acceptable energy densities (0.6–0.8 kcal/g) for child feeding.Publication Proximate Composition and Digestibility of Fermented and Extruded Uji From Maize– Finger Millet Blend(LWT - Food Science and Technology, 2004) Onyango Calvin; Noetzold Horst; Bley Thomas; Henle ThomasThe proximate composition, amino acid profile and in vitro starch and protein digestibilities of raw; fermented; fermented and cooked; unfermented and extruded; and fermented and extruded maize–finger millet blend was studied. Aspartic acid, glycine,cystine, methionine, tyrosine and lysine increased after fermentation, while contents of all other amino acids showed no significant changes. Greater losses of amino acids occurred when the fermented blend was extruded than when cooked. Fermentation improved protein and starch digestibilities, whereas cooking or extruding the fermented blend reduced the digestibilities. Extruding the unfermented blend increased protein and starch digestibilities and reduced nitrogen solubility index by 50%. Raw flour had 0.41 g/100 g water-soluble starch which declined to 0.05 g/100 g on fermentation but increased to 20–34 g/100 g after extrusionPublication Quality of Porridge from Sub-Saharan Africa Evaluated Using Instrumental Techniques and Descriptive Sensory Lexicon - Part 1: Thick (Stiff) Porridge(Academic Journals, 2018-04-30) Onyango Calvin; Wanjala George W.The sensory attributes of thick porridges made from different composite flours in neutral, citric acid or sodium bicarbonate media was identified using instrumental methods and modified quantitative descriptive analysis. The results showed that composite flours with high cassava concentrations had lower pasting temperatures but higher peak, breakdown, final and setback viscosities than the cereal-rich flours. The onset pasting temperatures of alkali-treated slurries were higher (p < 0.05) than for the neutral- or acid-treated slurries. Acid-treated slurries had higher (p < 0.05) peak viscosities than neutral- or alkali-treated slurries. Acid-treated slurries had higher (p < 0.05) breakdown viscosities as compared to the neutral slurries. The toughness and work of shear of thick porridge ranged between 0.21 - 0.58 kg and 0.83 - 5.95 kg·mm, respectively. Thick porridge cooked in alkaline media was significantly darker (p < 0.05) than that made in neutral or acid media. Principal component analysis identified four major principal components (PCs) that accounted for 87.6% of the total variance in the sensory attribute data. The principal component scores indicated that the location of each porridge along each of the four scales corresponded with attributes associated with sodium bicarbonate aroma and taste (PC1); cassava aroma and hardness (PC2); colour of thick porridge (PC3); and finger millet/sorghum aroma (PC4). Thick porridges targeting specific consumer groups in sub-Saharan Africa can be developed by appropriate choice of flours and pH thereby forming the basis for commercial production of thick porridges for different population categories in sub-Saharan Africa with diverse sensory expectations of the product.Publication Quality of Porridge rom Sub-Saharan Africa Evaluated Using Instrumental Techniques and Descriptive Sensory Lexicon - Part 1: Thick (Stiff) Porridge(Academic Journals of Food Science, 2018-04-30) Onyango Calvin; Wanjala George W.The sensory attributes of thick porridges made from different composite flours in neutral, citric acid or sodium bicarbonate media was identified using instrumental methods and modified quantitative descriptive analysis. The results showed that composite flours with high cassava concentrations had lower pasting temperatures but higher peak, breakdown, final and setback viscosities than the cereal-rich flours. The onset pasting temperatures of alkali-treated slurries were higher (p < 0.05) than for the neutral- or acid-treated slurries. Acid-treated slurries had higher (p < 0.05) peak viscosities than neutral- or alkali-treated slurries. Acid-treated slurries had higher (p < 0.05) breakdown viscosities as compared to the neutral slurries. The toughness and work of shear of thick porridge ranged between 0.21 - 0.58 kg and 0.83 - 5.95 kg·mm, respectively. Thick porridge cooked in alkaline media was significantly darker (p < 0.05) than that made in neutral or acid media. Principal component analysis identified four major principal components (PCs) that accounted for 87.6% of the total variance in the sensory attribute data. The principal component scores indicated that the location of each porridge along each of the four scales corresponded with attributes associated with sodium bicarbonate aroma and taste (PC1); cassava aroma and hardness (PC2); colour of thick porridge (PC3); and finger millet/sorghum aroma (PC4). Thick porridges targeting specific consumer groups in sub-Saharan Africa can be developed by appropriate choice of flours and pH thereby forming the basis for commercial production of thick porridges for different population categories in sub-Saharan Africa with diverse sensory expectations of the product.Publication Reactive Oxygen Species (ROS) Generation, Impacts on Tissue Oxidation and Dietary Management of Non-Communicable Diseases: A Review(African Journal of Biochemistry Research, 2017-12-31) Wanjala George Wafula; Onyango Arnold; Onyango Calvin; Makayoto MosesGeneration of reactive oxygen species (ROS) in biological systems has been reported to be a significant cause of inflammatory and metabolic diseases. More recently, ROS and in a particular ozone has also been implicated in the conversion of cholesterol to atherogenic compounds, secosterol A, and upon aldolization to secosterol-B. Secosterol-A is uniquely produced by cholesterol ozonolysis, while secosterol-B can also be generated through the reaction of cholesterol with singlet oxygen. On the other hand, lipid oxidation reactions generate hydroperoxides, which upon catalytic and/or enzymatic decomposition yields lipid peroxide products of significant importance to tissue health. The mechanism of formation of potent oxidants like ozone in biological systems has not been clearly demonstrated, with only a theory: That antibodies catalyze oxidation of water by singlet oxygen to yield a trioxidic species, like hydrogen trioxide, as an intermediate in hydrogen peroxide formation while a recent hypothesis indicates that ozone could also be an intermediate in the aforementioned pathway and could be generated from biological molecules in the presence of singlet oxygen. Similarly, there is new information being generated concerning the involvement of antioxidants and amino acids in either termination or propagation of oxidative processes in mammalian systems. This review explores mechanisms of ROS/ozone generation in tissues, lipid peroxidation, cholesterol oxidation and highlight dietary management of non-communicable diseases with a focus on the roles of antioxidants and amino acids.Publication Rheological And Baking Characteristics of Batter and Bread Prepared from Pregelatinised Cassava Starch and Sorghum and Modified Using Microbial Transglutaminase(Journal of Food Engineering, 2010) Onyango Calvin; Mutungi Christopher; Ubehend Gunter; Lindhauer Meinolf GThe effect of different concentrations (0, 0.5, 1 and 1.5 U/g) of microbial transglutaminase (MTG) on the creep-recovery properties of gluten-free batter prepared from pregelatinised cassava starch, sorghum and egg white was investigated. The test conducted in the rheometer had an instant loading of 80 Pa for 60 s and recovery of 0 Pa for 140 s. Increasing MTG concentration decreased the batters’ resistance to deformation and compliances but increased zero shear viscosity and elastic recovery. Changes in batter rheological properties were insignificant (P > 0.05) at MTG concentrations beyond 0.5 U/g. Crumb properties of gluten-free bread baked from the batter revealed that increasing MTG concentration increased (P < 0.05) crumb firmness and chewiness, whereas increasing incubation time decreased (P < 0.05) crumb cohesiveness, chewiness and resilience. There were no significant interaction effects (P > 0.05) between enzyme concentration and incubation timePublication Rheological And Textural Properties of Sorghum-Based Formulations Modified with Variable Amounts of Native or Pregelatinised Cassava Starch(LWT - Food Science and Technology, 2011) Onyango Calvin; Mutungi Christopher; Ubehend Gunter; Lindhauer Meinolf G.Sorghum bread was made from native or pregelatinised cassava starch and sorghum flour in the ratio 10:90, 20:80, 30:70, 40:60 and 50:50. The other ingredients, measured on flour-weightbasis, were water (100%), sugar (6.7%), egg white (6%), fat (2%), salt (1.7%) and yeast (1.5%). The dynamic oscillatory behaviours of the batters were affected by the amount and type of starch. In the amplitude sweep measurements, increasing concentration of native starch decreased storage modulus, whereas increasing concentration of pregelatinised starch increased the linear viscoelastic range of the batters. In the frequency sweep measurements, the loss factor of batters treated with native starch declined with increasing frequency. Batters treated with 10 or 20% pregelatinised starch showed declining loss factors, whereas batters treated with 40 or 50% pregelatinised starch showed increasing loss factors with increasing frequency. Sorghumbased batters containing native starch gave bread with better crumb properties than batters containing pregelatinised starch. Crumb firmness and chewiness declined with increasing native or pregelatinised starch concentration. Crumb adhesiveness of breads containing pregelatinised starch increased with increasing starch content but was not affected by native starch. Cohesiveness, springiness and resilience increased with increasing native starch content, but were minimally affected by increasing pregelatinised starch content.Publication Synthesis and In Vitro Digestion of Resistant Starch Type III from Enzymatically Hydrolysed Cassava Starch(International Journal of Food Science & Technology, 2008) Onyango Calvin; Mutungi ChristopherResistant starch type III (RS III) was synthesised from cassava starch by autoclaving followed by debranching with pullulanase, at varied concentrations (0.4–12 U g)1) and times (2–8 h), and recrystallisation ()18 to 90 C for 1–16 h). The highest RS III yield (22 g ⁄ 100 g) was obtained at an enzyme concentration of 4 U g)1 after 8 h incubation, followed by recrystallisation at 25 C for 16 h. Varying the recrystallisation conditions indicated that higher RS III yields (30–35 g ⁄ 100 g) could be obtained at 90 C within 2 h. Thinning cassava starch using a-amylase prior to debranching using pullulanase did not further increase the RS III content. In vitro digestion data showed that whereas 44% RS III was digested after 6 h, the corresponding value for cassava starch was 89%.Publication The Fate of Afiatoxins During Processing of Maize into Muthokoi - A Traditional Kenyan Food(ScienceDirect, 2008-07) Mutungi Christopher; Lamuka Peter; Arimi Samuel; Gathumbi James; Onyango CalvinThe effect of processing muthokoi, (a traditional dehulled maize dish in Kenya) on aflatoxin content of naturally contaminated maize was investigated. Dehulling decreased aflatoxin levels by 46.6% (5.5-70%) in maize samples containing 10.7-270 ngjg aflatoxin levels. Soaking muthokoi in 0.2%, 0.5% and 1.0% solutions iati, sodium hypochlorite or ammonium persulphate for 6 or 14 h further decreased aflatoxin contents by 28-72% in maize samples containing 107-363 ng/g aflatoxin levels, and boiling muthokoi at 98°C for 150 min in 0.2-1.0% w/v iati decreased aflatoxin contents by 80-93% in samples having 101 ng/g aflatoxin contamination. Findings imply that expo¬sure to acute aflatoxin levels in maize is minimised during processing and preparation of muthokoi.Publication The Pasting Behaviour of Lactic-Fermented and Dried Uji (An East African Sour Porridge)(Department of Food Technology and Nutrition, 2022) Onyango Calvin; Okoth Michael; Mbugua SamuelThe effects of sun-, cabinet-, and drum-drying on the behaviour of submerged culture lactic¬fermented pure cassava, maize and finger millet and composites of maize-finger millet and cassava-finger millet were investigated in a Brabender amylograph. The cereal flours and maize-finger millet composite had higher onset and peak gelatinization temperatures but lower peak viscosities than cassava or cassava finger millet composites. Fermentation alone or in combination with drying increased the viscosity of the flours, except for the fermented and drum-dried cassava-finger millet composite flour. This increased viscosity of uji on fermentation and drying makes it more difficult to cook.Fermented and drum-dried flours recorded high initial viscosities, at 30 "C, when the amylograph was switched on.