Food Nutrition

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Identification of Traditional Foods with Public Health Potential for Complementary Feeding in Western Kenya
(Journal of Food Research, 2012-05-01) Kinyuru, John; Konyole, Silvenus; Kenji, Glaston; Onyango, Christine; Owino, Victor; Owuor, Bethwell; Estambale, Benson; Friis, Henrik; Roos, Nanna
Abstract The diversity of traditional foods in Kisumu West District of Western Kenya was assessed with an aim toidentify the foods with a potential for complementary feeding. Leaves were the most consumed plant partamongst vegetables, while a few fruits were consumed together with theirseeds. Amaranthus cruentus L. wasfound to be consumed as a leafy vegetable while another variety, Amaranthus hybridus L. was found to beconsumed as a grain. Four species of wingedtermites, a grasshopper, black ant and dagaa fish were alsoidentified. Twelve of the traditional foods were found to be associated with nutritional and health benefits asperceived bythe locals. Traditional food processing methods such as boiling, fermentation and sun dryingwereidentified. Thus exploitation of the species possessing nutrient, health and processing benefits needs to beexplored in complementary feeding.
Acceptability of Amaranth Grain-based Nutritious Complementary Foods with Dagaa Fish (Rastrineobola argentea) and Edible Termites (Macrotermes subhylanus) Compared to Corn Soy Blend Plus among Young Children/Mothers Dyads in Western Kenya
(Canadian center of science and education, 2012-07) Konyole S. O; Kinyuru J N; Owuor B. O; Kenji G. M; Onyango C. A; Estambale B.B; Henrik Friis; Nanna Roos; Owino V.O
Abstract We assessed acceptability of two flours and porridges of complementary foods based on germinated grain amaranth and maize with or without edible termites and dagaa small fish named “Winfood Classic” (WFC) and “Winfood Lite” (WFL), respectively, compared to Corn Soy Blend Plus (CSB+) among mothers and young children. A total of 57 children consumed each of the three foods on separate days with one-day washout between foods. Each food was considered acceptable if the child consumed at least 75% of the serving. Most mothers preferred WFL flour and porridge (63.2% and 70.2%, respectively) compared to WFC (24.4% and 10.5%) and CSB+ (12.3% and 19.3%). Children consuming at least 75% of served porridge were 43%, 19.6% and 21% for WFL, WFC and CSB+, respectively. No adverse effects were observed for all the foods throughout the study period and follow up lasting 4 weeks. All foods were acceptable and can be further developed and be tested for efficacy.
Nutrients, Functional Properties, Storage Stability and Costing of Complementary Foods Enriched with Either Termites and Fish or Commercial Micronutrients
(Wageningen Academic Publishers, 2015) Kinyuru J.N.; Konyole S.O.; Omolo S.A. Onyango; Kenji G.M.; Onyango C.A.; Owino V.O.; Owuor B.O.; Estambale B.B.; Roos N.
Application of edible insects in complementary food production has not been studied much. This study developed and evaluated complementary foods based on edible termites to combat child malnutrition in Kenya. Two complementary foods, Winfood Classic (W-C; containing termites and dagaa fish) and Winfood Lite (W-L; without termites and dagaa fish) were formulated and processed by extrusion cooking. Their nutrient content, functional properties, storage stability and cost of the foods were evaluated using standard methods. W-C contained significantly higher (P=0.37). The energy contribution from fats (26.1 E%) from W-C was within the recommend levels in complementary foods while energy from proteins (protein E%) was higher from the two foods (18.0 and 14.3 E%, respectively). Bulk density was significantly different (P=0.02) amongst W-C and W-L and within the recommended levels of ≤0.5 g/cm3 in complementary foods. The foods were shelf stable for 6 months of storage with neither pathogenic microorganisms nor aflatoxins reported. Peroxide value was below the limits (≤10 meq/kg) after 6 months of storage. Production cost of the foods was 3.21 and 2.23 US$/kg for W-C and W-L, respectively, with termites contributing 42.3% of the basic cost of production in W-C. The study confirms that termites and dagaa fish can be utilised in processing of affordable and safe complementary foods with adequate nutrient density.
Functionalization of Sweet Potato Leaf Polyphenols by Nanostructured Composite Β-Lactoglobulin Particles from Molecular Level Complexations: A Review
(Elsevier, 2022-03) Makori Shadrack Isaboke; Mu Tai-Hua; Sun Hong-Nan
Sweet potato leaf polyphenols (SPLPs) have shown potential health benefits in the food and pharmaceutical industries. Nowadays, consumption of SPLPs from animal feeds to foodstuff is becoming a trend worldwide. However, the application of SPLPs is limited by their low bioavailability and stability. β-lactoglobulin (βlg), a highly regarded whey protein, can interact with SPLPs at the molecular level to form reversible or irreversible nanocomplexes (NCs). Consequently, the functional properties and final quality of SPLPs are directly modified. In this review, the composition and structure of SPLPs and βlg, as well as methods of molecular complexation and mechanisms of formation of SPLPsβlgNCs, are revisited. The modified functionalities of SPLPsβlgNCs, especially protein conformational structures, antioxidant activity, solubility, thermal stability, emulsifying, and gelling properties including allergenic potential, digestibility, and practical applications are discussed for SPLPs future development
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 Fredrick
The 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.
Sweet Potato Chemistry, Processing and Nutrition
(Charlotte Cockle, 2019) Mu, Tai-Hua; Singh, Jaspreet
This chapter provides an overall introduction to the sweet potato. It starts with a general description of the sweet potato. It then summarizes the characteristics of the starch, protein, dietary fiber, pectin, lipids, polyphenols, and carotenoids of the sweet potato. At the end of the chapter, information on sweet potato staple products and snack foods is presented.
Fatty Acids Composition of Nile Tilapia (Oreochromis Niloticus) Fingerlings Fed Diets Containing Different Levels of Water Spinach (Ipomoea Aquatica)
(Journal of Agriculture and Food Research, 2021) Chepkirui M.; Orina P. S.; Opiyo M.; Muendo P.; Mbogo K.; Omondi R.
Fish is a major source of n-3 LC-PUFA for humans. Fatty acids especially n-3 and n-6 polyunsaturated fatty acids (PUFAs) play important role in human health. This study was conducted to evaluate the effects of different inclusion levels of Ipomoea aquatica on fatty acids composition of Oreochromis niloticus fingerlings. Five diets containing 0%, 5%, 10%, 15% and 20% Ipomoea aquatica were formulated. The results indicated that 18 types of fatty acids with different saturation levels were detected. Total saturates, n-3 PUFAs, n-6 PUFAs in all the tissues were not significantly affected by the different levels of I. aquatica. Fish fed 10% diet recorded the highest level of muscle docosahexaenoic acid (DHA). The tissue composition of docosahexaenoic acid (DHA) was significantly higher than eicosapentaenoic acid (EPA). There was an increase in PUFAs with increased levels of I. aquatica. There was no significant difference (P > 0.05) in fatty acids in all the tissues. The study suggests that 20% dietary inclusion of I. aquatica resulted into high DHA in all tissues thus I. aquatica can be used to increase fatty acid.
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. Meinolf
The 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.
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. Meinolf
The 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).
Colonization Patterns of Benthic Macroinvertebrates in Fertilized And Non-Fertilized Earthen Fish Ponds
(International Journal of Aquaculture and Fishery Sciences, 2018) Orwa Patrick; Omondi Reuben; Chemoiwa Emily
International Journal of Aquaculture and Fishery SciencesISSN: 2455-8400CC By022Life Sciences Group Citation: Orwa PO, Omondi R, Chemoiwa EJ (2018) Colonization patterns of benthic macroinvertebrates in fertilized and non-fertilized earthen fish ponds. Int J Aquac Fish Sci 4(3): 022-026. DOI: http://doi.org/10.17352/2455-8400.000039http://doi.org/10.17352/24558400.000039DOIanAbstractStudy conducted in Kwanza, Trans-Nzoia County to determine the colonization pattern of benthic macroinvertebrates in earthen fi sh ponds. This was done to ascertain the right stocking time of ponds when the natural fi sh food is in plenty. Two ponds were used for this study; one was treated with organic manure while the other was not fertilized. Sampling for physico-chemical parameters were then taken immediately after fi lling the ponds and repeated weekly for six weeks while benthic macroinvertebrates were fi rst sampled after week 1 and repeated weekly for six weeks. The results obtained were compared between the two treatments and per treatment over time. There were signifi cant differences in most parameters over the weeks and between the treatments. Attainment of suitable conditions for stocking was however at week 3 for fertilized and week 4 for the non-fertilized contrary to the usual two week period advised by most procedures
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.
Quality of Porridge from Sub-Saharan Africa Evaluated Using Instrumental Techniques and Descriptive Sensory Lexicon - Part 1: Thick (Stiff) Porridge
(African Journal 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 cerealrich 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 neutralor 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.
Quality of Porridge from Sub-Saharan Africa Evaluated Using Instrumental Techniques and Descriptive Sensory Lexicon. Part 2: Thin Porridge
(African Journal of Food Science, 2018-05-31) Onyango, Calvin; Wanjala, George W.
Thin porridge is a popular nourishment drink for adults and complementary food for children in sub-Saharan Africa. It is made from straight (unblended) or composite flours of maize, sorghum, finger millet and cassava in neutral or chemically-acidified media, or after spontaneous fermentation of the flours. The objective of this study was to determine the impact of type of composite flour and pH on the sensory quality of thin porridges. Instrumental methods and modified quantitative descriptive analysis were used to identify the main sensory attributes of thin porridges made from different composite flours in neutral or acidic media or after spontaneous fermentation. The results of the study indicated that irrespective of the pH, cerealbased composite flours had higher onset pasting temperatures; and lower peak, breakdown, final and setback viscosities than cassava-cereal flours. Thin porridges formulated from cereal-based composite flours tended to have lower firmness, consistencies, cohesiveness and indices of viscosity than those made from cassava-cereal flours. The colour of thin porridges depends on the botanical origin of the composite flours, their ratios and whether the pH was adjusted using citric acid or by spontaneous fermentation. Principal component analysis identified three major principal components (PCs) that accounted for 83.7% of the total variance in the sensory attribute data. The principal component scores indicated that the location of the thin porridges on each of the three scales corresponded with cassava aroma (PC1), finger millet/maize aroma (PC2), and colour and fermented aroma (PC3). This study has shown that thin porridges with different sensory profiles can be produced in sub-Saharan Africa for different population groups.
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; Arnold. Onyango; Calvin, Onyango; Moses. Makayoto
Generation 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.
Composition of Polyphenols in Wheat Bread Supplemented with Pleurotus ostreatus Mushroom
(American Journal of Food Technology, 2015) Ndung'u, Stella W.; Otieno, Christina A.; Onyango, Calvin; Musieba, Fredrick
Pleurotus ostreatus mushrooms were blanched, milled into flour and incorporated into wheat flour at 5, 10 and 15%. These composite flours, together with composite breads developed from these formulations were evaluated for polyphenols, namely flavones and isoflavones. Wheat flour and wheat bread were used as control samples. Extraction of polyphenols was done using ethanol as a solvent and analyzed using gas chromatographmass spectrometry. It was not possible to make bread with 15% mushrooms. Quantities of different flavones and isoflavones evaluated increased significantly (p<0.05) with increasing supplementation of mushroom flour in wheat flour. Composite breads were also observed to have higher contents of flavones and iso flavones as compared to bread prepared from wheat flour only. Composite flour with 15% mushrooms had highest quantities of flavones and isoflavones while composite bread with 10% mushroom flour had significantly higher (p<0.05) levels of these compounds. Caffeic acid was the most abundant amongst all the flavones analyzed in wheat mushroom blends while genistein was the most abundant isoflavone. Flavones and isoflavones in human nutrition protect against oxidative stress and also provide medicinal properties such as antimicrobial, antiviral and anticancer benefits. Pleurotus mushrooms are a good source of these important compounds hence incorporating them in daily diet like bread would ensure constant supplementation for improved health and nutrition.
Long- and Short-Range Structural Changes of Recrystallised Cassava Starch Subjected To In Vitro Digestion
(Food Hydrocolloids, 2011-05) C. Mutungi; C. Onyango; T. Doert; S. Paasch; S. Thiele; S. Machill; D. Jaros; H. Rohm
The conformational and structural order of resistant starch type III made from cassava starch was studied. The gelatinized starch was debranched using pullulanase and then recrystallised by annealing, temperature-cycling or heat-moisture treatment. Subsequently, the recrystallised products were subjected to in vitro digestion using porcine pancreatic α-amylase and amyloglucosidase. The undigested and digested products were analyzed for polymer chain distribution, crystallinity, molecular order, structural conformations and thermal stability using high performance anion exchange chromatography, wide angle X-ray diffraction, Fourier transform infrared spectroscopy, 13C CP/MAS nuclear magnetic resonance and differential scanning calorimetry, respectively. Average degree of polymerisation increased from 20 to 22 glucose units upon digestion. Both the undigested and digested starches comprised mixtures of A, B and V crystalline types. Percentage of crystallinities by X-ray diffraction were 40.9%, 50.7% and 56.2% in annealed, temperature-cycled and heat-moisture treated starches, respectively. These values increased to 47.9%, 54.4% and 58.2%, respectively, in the digested products. The ordered fractions in the undigested annealed, temperature-cycled and heat-moisture treated starches were 69.3%, 71.4% and 79.2%, respectively, as determined by 13C CP/MAS nuclear magnetic resonance. However, the disordered phase was indistinct in the digested products although the contents of non-crystalline conformations were significantly (p < 0.01) higher. The melting enthalpies of the digested residues increased by factors of 2.50 in annealed, 2.53 in temperature-cycled and 2.06 in heat-moisture treated starches, suggesting molecular rearrangement in a manner related to the enzyme susceptibility of the initial materials.
Dynamic Moisture Sorption Characteristics of Enzyme-Resistant Recrystallized Cassava Starch
(American Chemical Society, 2011-01-24) Christopher Mutungi; Stefan Schuldt; Calvin Onyango; Yvonne Schneider; Doris Jaros; Harald Rohm
The interaction of moisture with enzymeresistant recrystallized starch, prepared by heat-moisture treatment of debranched acid-modified or debranched non-acid-modified cassava starch, was investigated in comparison with the native granules. Crystallinities of the powdered products were estimated by X-ray diffraction. Moisture sorption was determined using dynamic vapor sorption analyzer and data fitted to various models. Percent crystallinities of native starch (NS), non-acidmodified recrystallized starch (NAMRS), and acid-modified recrystallized starch (AMRS) were 39.7, 51.9, and 56.1%, respectively. In aw below 0.8, sorption decreased in the order NS > NAMRS > AMRS in line with increasing sample crystallinities but did not follow this crystallinity dependence at higher aw because of condensation and polymer dissolution effects. Adsorbed moisture became internally absorbed in NS but not in NAMRS and AMRS, which might explain the high resistance of the recrystallized starches to digestion because enzyme and starch cannot approach each other over fairly sufficient surface at the molecular level.
Effect Of Heat-Moisture-Treated Cassava Starch and Amaranth Malt on The Quality of Sorghum-Cassava Amaranth Bread
(African Journal of Food Science, 2013-05-31) Calvin Onyango; Eunice A. Mewa; Anne W. Mutahi; Michael W. Okoth
Gluten-free batter and bread was prepared from modified cassava starch, sorghum and amaranth flour. Heat-moisture treatment (80°C, 18, 24 or 30% moisture content, and 8, 16 or 24 h incubation) of cassava starch increased its crystallinity, onset pasting temperature and water absorption index; and decreased its swelling power, water solubility index and peak viscosity. Heat-moisture treated cassava starch was made into batter with sorghum and amaranth in the ratio of 50:40:10. The other ingredients, weighed on flour-weight-basis, were water (75%), sugar (6.7%), fat (2%), salt (1.7%), and amaranth malt at 0, 1 or 2.5%. The interaction effect (that is, starch modification x amaranth malt) significantly (P ≤ 0.05) affected batter consistency. Breads made from heat-moisture treated starch were softer than those containing native starch. The interaction effect (that is, starch modification x amaranth malt) was significant (P ≤ 0.05) only for the texture profile analysis property of cohesiveness. Further investigation of the effect of heat-moisture treatment showed that the interaction effect (that is, moisture content x incubation time) significantly (P ≤ 0.05) affected only the Texture Profile Analysis properties of hardness and chewiness.
Physical Properties of Dry-Milled Maize Meals and Their Relationship with the Texture of Stiff and Thin Porridge
(African Journal of Food Science, 2014) Calvin Anyango
Selected physical properties of white maize meal, obtained by different dry-milling techniques were evaluated and correlated to the texture of stiff and thin porridge. Sifted or par-cooked maize meals had finer particles than hammer-milled maize meals. Hammer-milled maize meals had lower water absorption indices (17-38%) and higher water solubility indices (WSI, 4-5%) than sifted (41-42 and 2-3%, respectively) or par-cooked (114 and 2%, respectively) maize meals. Sifted or par-cooked maize meals had lower breakdown viscosities (0-19 BU) and higher final viscosities (818-1925 BU) than hammer-milled maize meals (89-173 BU and 530-780 BU, respectively). Stiff porridge prepared from par-cooked maize meal (34% w/v), and thin porridge from dehulled and hammer-milled maize meal (10% w/v) had the firmest textures at 80.93 and 1.28 N, respectively. There was a negative correlation (P < 0.05, r = -1.00) between the WSI and total shearing force of stiff porridge prepared from par-cooked maize meal.
Rheological Properties of Wheat-Maize Dough and Their Relationship with the Quality of Bread Treated with Ascorbic Acid and Malzperle Classicâ® Bread Improver
(African Journal of Food Science, 2015-02-28) Calvin Onyango; Ljiljana Unbehend; Guenter Unbehend; Meinolf G. Lindhauer
The aim of this work was to investigate the effect of ascorbic acid and a commercial bread improver on the physical quality of wheat-maize bread, and establish correlations between the physical properties of the bread and rheological properties of the dough. Wheat flour was substituted with 10, 20 or 30% maize flour and the farinograph and extensograph properties of the dough were evaluated. Farinograph water absorption, dough development time, dough stability and farinograph quality number decreased whereas the degree of softening increased with increasing substitution of wheat flour with maize flour. Extensograph dough energy, resistance to extension, extensibility and maximum resistance decreased with increasing substitution of wheat flour with maize flour. Ascorbic acid and commercial bread improver improved bread specific volume and form ratio; decreased crumb firmness, resilience and chewiness; and increased crumb springiness and cohesiveness. Farinograph water absorption and degree of softening; and extensograph energy, extensibility, maximum resistance and ratio number showed the highest number of significant correlations (P ≤ 0.01 or P ≤ 0.05) with the physical properties of wheat-maize bread.

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