Food Security

Permanent URI for this community

https://repository.nrf.go.ke/handle/123456789/783

Browse

Now showing 1 - 20 of 215

Preliminary Study on The Food and Feeding Habits of Schilbe Mystus (Linn., 1762) in River Nyando
(ICIPE SCIENCE, 1994) Reuben Omondi; James Ogari
Schilbe mystus (Butlerfish) is one of the "endangered species" of Lake Victoria, whose fishery was once of commercial importance. The annual landings have declined from about 400 mt in 1968 to a bare 15 mt in 1991. The average size of the species is smaller than that reported by Greenwood (1 966). During the study, the size range sampled was 11.2 to 25.6 cm. fork length with the majority measuring 14.0-15.0 cm FL. The food and feeding habits of the fish are discussed. Study on the gut content shows that Schilbemystuspreys mainly on insects with chironomid larvae as the dominant Prey.
Effect of Drying Lactic Acid Bacteria Fermented Uji on Its Pasting Properties and Content of Carboxylic Acids
(University of Nairobi Department of Food and Nutrition Technology, 1999-01-01) Onyango, Calvin; Okoth, Michael; Mbugua, Samuel
The effect of fermentation and drying on the pasting properties and carboxylic acids of pure flours of maize, finger millet and cassava and of composite flours of maize-finger millet and cassava-finger millet were studied. The pasting properties were measured between 30°C and 96°C in a Brabender Amylograph while carboxylic acids from the uji slurries were determined on thin layer chromatography plates coated with 0.25 mm silica gel. Irrespective of the treatment given, the cereal flours of maize, finger millet and the composite of maize-finger millet consistently had higher onset and peak gelatinization temperatures than pure cassava or the composite of cassava-finger millet. Also the latter two flours developed higher peak viscosities and disintegrated more rapidly after attaining the peak than either pure maize, finger millet or the composite of maize-finger millet. The higher viscosities of the root flours was also reflected in the higher swelling powers and solubility values at 85°C. Fermentation increased the viscosity of the slurries. The greatest increases were recorded by maize (500BU) and the composite of maizefinger millet (780 BU). Fermentation did not affect gelatinization temperatures except for the maize-finger millet composite whose gelatinization temperature decreased by 10°C. Fermentation and drying resulted in increased viscosity when compared to the non-fermented flours, except for the drum dried cassava-finger millet composite. For all the drum dried flours there was a spontaneous increase in viscosity at 30°C when the Brabender Amylograph was switched on. The drum dried flours absorbed about four times their own weight of water; and since the starch granules were pregelatinized, reconstitution in cold water was difficult, as the flour particles tended to lump together, getting wetted on the surface and inhibiting the penetration of water into the interior. In contrast, sun and cabinet dried flours absorbed about 1.9 times their own weight of water and formed smooth slurries in cold water. Fermentation increased total titratable acidity and fixed acidity of the slurries to about 3.9% and 3.6% respectively, while the pH declined from 5.5 to 3.9. On drying there were no significant changes in (p0.05) from the uji prepared from fermented and nondehydrated slurries.
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 Christopher
Resistant 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%.
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).
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 Harald
Cassava 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).
Crystallinity, Thermal and Morphological Characteristics of Resistant Starch Type III Produced by Hydrothermal Treatment of Debranched Cassava Starch
(Wiley Online Library, 2009-11-25) Mutundi C.; Rost F.; Onyango C.; Henle D.; Rohm H.
Cassava starch was debranched using pullulanase and the linear glucans recrystallized by incubation at 60°C or by temperature cycling at 120/60°C, and further subjected to heat-moisture treatment (HMT). Resistant starch (RS III) contents increased from 21.4 g/100 g in the debranched starch (DS) to 67.3 g/100 g in the debranched starch incubated at 60°C (DRS) and 47.8 g/100 g in the debranched starch subjected to temperature cycling (DCS), and further to 84.8 g/100 g and 88.4% g/100 g in HMT-DRS and HMT-DCS, respectively. Total crystallinity varied between 31.4-59.8% and the crystalline type was C in DS and DRS and A in DCS, HMTDRS and HMT-DCS. The melting properties were characterized by broad endotherms, but the exact melting region and enthalpy were dependent on recrystallization method. The main endothermic peaks of DS and DRS occurred at 103.9 and 109.8°C, respectively, whereas DCS exhibited split endotherms at 113.6 and 138.1°C. Heat-moisture treatment broadened the endotherms and increased their enthalpies. Scanning electron micrographs revealed surface topography differences related to size and aggregation of individual crystalline bodies.
Structural And Physicochemical Properties And In Vitro Digestibility of Recrystallized Linear Α-D- (1 → 4) Glucans Derived from Mild-Acid-Modified Cassava Starch
(Food Research Internationa, 2010) Mutungi C.; Onyango C.; Rost F.; Doert T.; Rohm H.; Jaaros D.
Molecular structure and recrystallization method influence the techno-functional behaviour of recrystallized starch as a functional ingredient in foods. The physicochemical properties of debranched and recrystallized mild-acid-modified cassava starch were studied. Cassava starch was treated with 0.14 mol/L hydrochloric acid for 24, 96 and 216 h at 40 °C prior to debranching with pullulanase. The debranched starches (DS) were recrystallized by annealing (ANN-DS), temperature-cycling (TC-DS) or heat-moisture treatment (HMT-DS) and the particle distribution, crystallinity, thermal properties, solubility, water binding and in vitro digestibility were analyzed. Acid treatment increased the fraction of linear α-d-(1 → 4) glucans comprising 13–30 monomers. Particles comprised loosely to firmly coalesced primary elements forming aggregates of mono- or bi-modal size distribution at ⩽5 μm and ⩾20 μm. The relative crystallinities ranged between 31.1–56.1%. Water binding decreased significantly with acid treatment whereas both solubility and water binding were influenced by the recrystallization method and decreased in the order: DS > ANN-DS > TC-DS > HMT-DS. Major thermal transitions occurred at 80– 130 °C and 130–160 °C, and the in vitro digestibility rates of 6.8–62.8% correlated significantly (p < 0.001) with relative crystallinity and melting enthalpy.
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 G
The 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 time
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.
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.
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.
Modification Of Gluten-Free Sorghum Batter and Bread Using Maize, Potato, Cassava or Rice Starch
(LWT - Food Science and Technology, 2011-04) Calvin Onyango; Christopher Mutungi; Günter Unbehend; Meinolf G. Lindhauer
Gluten-free sorghum bread was made from cassava, maize, potato or rice starch and sorghum in the ratios 10:90, 20:80, 30:70, 40:60 and 50:50. The other baking ingredients, on flour-weight-basis, were water (100%), sugar (6.7%), egg white powder (6%), fat (2%), salt (1.7%) and yeast (1.5%). Increasing starch content changed the batters’ consistencies from soft doughs to thin pourable batters. Increasing starch content decreased crumb firmness and chewiness, and increased cohesiveness, springiness and resilience of all breads. Cassava-sorghum and rice-sorghum breads had better crumb properties than maize-sorghum or potato-sorghum breads. Although the crumb properties of all breads declined (i.e. firmness and chewiness increased; cohesiveness, resilience and springiness decreased) on storage, the formulation containing 50% cassava starch retained the best overall texture.
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.
Genotype by environment interactions and yield stability of stem borer resistant maize hybrids in Kenya
(2011-06-01) Yoseph Beyene; Stephen Mugo; Charles Mutinda; Tadele Tefera; Haron Karaya; Sammy Ajanga; Jackson Shuma; Regina Tende; Vincent Kega
In a maize breeding program, potential genotypes are usually evaluated in different environments before desirable ones are selected. Genotype x environment (G x E) interaction is associated with the differential performance of genotypes tested at different locations and in different years, and influences selection and recommendation of cultivars. Twenty one stem borer resistance maize hybrids and four commercial checks were evaluated in six environments in Kenya under infestation with Chilo partellus and Busseola fusca to determine the G x E interactions and stability of the hybrids. Analysis of variance was conducted for grain yield, days to flowering and plant and ear height. Stability for grain yield was determined using genotype plus genotype by environment interaction (GGE) biplot analysis. Variances due to genotype, environment and G x E interaction effects were highly significant for all traits. The GGE biplot showed that four experimental hybrids and two commercial checks had positive PC1 score indicating above average performance across environments. However, 10 experimental hybrids and two commercial checks had negative PC1 score, suggesting poor average performance. Experimental hybrids, CKIR07004 and CKIR07013, were highly desirable in terms of grain yield (>7.5 t/ha) and stability across environments. These hybrids could be released in Kenya and similar environments.
A demand analysis for Sahiwal breeding animals from the national sahiwal stud (NSS) between 1971 and 2007
(2012) Mailu, Stephen; Ndambiri, Hillary; Ritho, C.; Nganga, S. I.; Miyancha, S. O.; Omboto, P.; Gudeta, Sileshi; Kibowon, Philip
The main objective of this working paper is to trace the development of demand for Sahiwal breeding stock over the period 1971-2007. Such an analysis will enhance our understanding of what has happened on the demand side within the study period. There is only a handful of Sahiwal breeding farms existing in the country, which implies that a particular market structure exists. This paper thus traces the likely evolution of demand and provides some insights on what has happened over the period since 1971. The year 1971 was upon decided as a starting point for the simple pragmatic reason that data for earlier years may not be available. Demand indicators assembled from the records at KARI-Naivasha are used to establish the trends of demand in order to predict the likely trajectory of demand in the near future. Time series analysis of data shows the probability of demand for bulls to have been on a downward trend while for heifers, it has been increasing over time. Also critical in this result is that the probability for heifer crosses is soon catching up with demand for heifers and bulls and given these trends, this may be the animal in greatest demand. Results for average request sizes are mixed with an increase in the size of requests for bulls and heifer crosses until 1990s and a drop in the size of requests since. Some parts of the country also appear to have dropped off, notably Coast Province while others (North Eastern) are rare demand centres. A second part of the analysis, which involves the estimation of models that explain these trends, provides a framework within which the role of important demand shifting parameters such as prices, production systems and distances is determined in greater detail
Characteristic effects of drying processes on bioactive compounds in african eggplant
(JKUAT, 2012) Mbondo, Naomi Nammaiyan; Prof. Willis O. Owino, PhD; Prof. Daniel N. Sila, PhD; Dr. Jane Ambuko, PhD
African eggplant (Solanum aethiopicum L.) is a rich source of bioactive compounds and functional constituents that are beneficial to human health. However, the short (3-5 days) shelf life can be a major cause of postharvest losses especially during peak harvesting season. Drying technology is a convenient way of producing shelf stable food products, but can lead to thermal degradation of available nutrients and bioactive compounds depending on the drying method and temperature conditions. Monitoring the changes in bioactive compounds is important for optimizing and choosing drying methods and conditions.The objective of this study was to investigate the effect of harvesting maturity on the drying characteristics; to determine the effect of four drying methods (solar, hot air oven, vacuum oven and freeze) on the retention of total phenolics, beta carotene, antioxidant capacity, vitamin C and lycopene; to determine the degradation kinetics of total phenolics, beta carotene and antioxidant activity during hot air oven and vacuum oven drying; and to establish consumer acceptability of the dried and reconstituted products through sensory evaluation. Five African eggplant (Solanum aethiopicum) accessions (sangawili, manyire green, S00047A, AB2 and aubergine blanche) were used in the study. Harvesting was carried out at two maturity stages defined by the peel shininess, colour and number of days between planting and harvest. Stage 1 maturity had a shiny peel while stage 2 maturity had a non-shiny peel. Samples were dried up to ~10% moisture content in a single layer. Random sampling was done at regular intervals as the drying process progressed. Subsequently, fresh and dried samples were analyzed for moisture content, total phenolics, beta carotene content, vitamin C, lycopene content and antioxidant capacity. Affective testing using 7 point hedonic scale was used for sensory evaluation through a consumer panel to establish the likability scores for the dried and reconstituted samples. The results showed that harvesting maturity significantly (p<0.05) effected the moisture content and the drying rate of the five accessions. Moisture content decreased from stage 1 maturity to stage 2 by up to 2.01% with the exception of AB2. The drying rates were higher for stage 1 maturity in comparison to stage 2. The drying time for stage 1 and stage 2 maturities was 360-840 and 360-960 minutes, respectively. In the fresh state, beta carotene, total phenolics and antioxidant activity ranged between 14.75-29.50 mg/100g db, 751.21-1363.95mg/100g gallic acid equivalent (GAE) db and 99.58-325.61mg/ml db percentage inhibition at 50% (IC50) value, respectively. The results showed a significant (p=0.001) positive correlation (r=0.822) between the total phenolics and the antioxidant equivalent ascorbic acid capacity. However, drying processes significantly (p<0.05) reduced the total phenolics, beta carotene and antioxidant capacity with freeze drying presenting the highest retention rate. Overall, 36.26 – 95.05% (total phenolics) and 31.44 – 99.27% (beta carotene) was retained during freeze drying. Lycopene was only detected in the dried samples of the accession manyire green. Also, vitamin C was undetected in both fresh and dried samples. The kinetics of degradation of total phenolics, beta carotene content and antioxidant activity followed a first-order reaction for both hot air oven and vacuum oven drying. The range of reaction rate constant was 0.018-0.067, 0.016-0.226, xx and 0.0237-0.453 h-1 for total phenolics, beta carotene and antioxidant activity, respectively. Activation energy range was 8.246-23.548, 15.994-60.845, 11.111-25.764 kJ/mol for total phenolics, beta carotene and antioxidant activity, respectively. Regarding the sensorial evaluation, it was not possible to clearly distinguish the sensory profiles of the five accessions statistically. The drying characteristics and degradation kinetics information from this study may be applied by farmers and industrialists in the development of optimum drying controls plan.
Testcross performance of doubled haploid maize lines derived from tropical adapted backcross population
(2012) Yoseph Beyene; Stephen Mugo; Kiru Pillay; Tadele Tefera; Sammy Ajanga; Stephen Njoka; Haron Karaya; John Gakunga
Doubled haploid (DH) lines produced by in vivo induction of maternal haploids are routinely used in maize breed ing. The present study was carried out to assess the performance of 75 doubled haploid maize testcrosses and six checks tested across four locations in Kenya for grain yield, agronomic traits and reaction to major leaf diseases. The 75 DH lines were derived from the backcross (BC1) plants of two CIMMYT bi-parental crosses. Significant location, genotype and genotype x location effects were observed for grain yield and anthesis-silking interval (ASI). Genotypes were significantly different for reaction to leaf blight and gray leaf spot. Location explained 69% of the total phenotypic variance while both genotype and genotype by environment interaction effects contributed 4% each. Fifteen DH testcross hybrids yielded better than the best commercial check, WH505 (5.1 t/ha). The best DH testcross hybrid (CKDHH0223) averaged over the four locations yielded 29.5% higher than WH505. These results indicate that maize testcrosses developed from DH lines produced as high a grain yield and as acceptable agro nomic traits as the commercial hybrids developed through conventional pedigree methods. The DH lines identified in the study may be useful for improving yield and disease resistance in maize breeding programs in eastern and southern Africa.
University Outreach Support to Farmer Associations in Western Kenya: The Case of The RUFORUM’s Community Action Research Project (CARP) at Moi University | RUFORUM Institutional Repository
(Ruforum, 2012) Okalebo, J.R.; Othieno, C.O.; Ochuodho, J.O.; Kipkoech, A.K.; Otinga, A.N.; Mongare, P.O.; Olal, D.A.; Navalayo, C.; Sunda, W.; Soi, C.C.; Woomer, P.L.
Moi University’s School of Agriculture obtained a research grant from the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM) under the Community Action Research Program (CARP) to carry out a research leading to the strengthening of the linkages between the universities and farmer associations. This is part of an endeavor to promote agricultural production in western Kenya. The Project linked with three Farmer Associations (FAs) in western Kenya in developing research programs and for disseminations of research findings. Field demonstrations were setup to refine and adapt new high yielding production technologies. The Project has enabled FAs develop their business plans, initiate contract farming to produce striga tolerant seed maize, increased sorghum production, improved management of FAs and built the capacity of FAs to undertake value addition. Three machines have been purchased for each for the three FAs to undertake value addition leading to marketing of finished pure or fortified soyabean and groundnut products. The project activities has brought FAs to a stage towards self sustainability and income generation.
Assessing Nutrient Intake and Nutrient Status of HIV Seropositive Patients Attending Clinic at Chulaimbo Sub-District Hospital, Kenya
(wiley publishers, 2012) Onyango, Agatha Christine; Walingo, Mary Khakoni; Mbagaya, Grace; Kakai, Rose
Background. Nutritional status is an important determinant of HIV outcomes. Objective. To assess the nutrient intake and nutrient status of HIV seropositive patients attending an AIDS outpatient clinic, to improve the nutritional management of HIV-infected patients. Design. Prospective cohort study. Setting. Comprehensive care clinic in Chulaimbo Sub-District Hospital, Kenya. Subjects. 497 HIV sero-positive adults attending the clinic. Main Outcome Measures. Evaluation of nutrient intake using 24-hour recall, food frequency checklist, and nutrient status using biochemical assessment indicators (haemoglobin, creatinine, serum glutamate pyruvate (SGPT) and mean corpuscular volume (MCV)). Results. Among the 497 patients recruited (M : F sex ratio: 1.4, mean age: 39 years ± 10.5 y), Generally there was inadequate nutrient intake reported among the HIV patients, except iron (10.49 ± 3.49 mg). All the biochemical assessment indicators were within normal range except for haemoglobin 11.2 g/dL (11.4 ± 2.60 male and 11.2 ± 4.25 female). Conclusions. Given its high frequency, malnutrition should be prevented, detected, monitored, and treated from the early stages of HIV infection among patients attending AIDS clinics in order to improve survival and quality of life.

Browse

Browsing Food Security by Issue Date

Results Per Page

Sort Options