Kenya Industrial Research and Development Institute

Nairobi, Kenya

Kenya Industrial Research and Development Institute

Nairobi, Kenya
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Wanjala G.W.,Kenya Industrial Research and Development Institute | Wanjala G.W.,Jomo Kenyatta University of Agriculture and Technology | Mathooko F.M.,Machakos University | Kutima P.M.,The County Government of Kakamega | Mathara J.M.,Jomo Kenyatta University of Agriculture and Technology
African Journal of Food, Agriculture, Nutrition and Development | Year: 2017

The microbiological quality of raw and pasteurized milk marketed in Nairobi and its environs was determined. Milk samples were collected randomly at milk selling points from three market areas: rural (Kiambu/Ngong), urban (East/West of Tom Mboya street) and slum (Kibera/Mathare). Samples were analysed for titratable acidity, total viable count (TVC), Staphylococcus aureus, coliforms and Enterobacteriaceae. Titratable acidity was determined using titration method, while TVC, S. aureus and Enterobacteriaceae were determined by the spread plate methods and coliforms were determined by most probable number. Data collected were subjected to analysis of variance using Genstat statistical package. The mean acidity was 0.20% lactic acid (LA), while mean counts for TVC, S. aureus, coliforms and Enterobacteriaceae were 6.05, 3.46, 2.30, and 3.93 log10cfu/ml, respectively. The percentage of milk samples with acidity values greater than 0.18% LA, the upper limit set by Kenya Bureau of Standards (KEBS), was 52.8 %. Total viable count (TVC) greater than 106 cfu/ml, was detected in 95.2% and 21.4% of raw and pasteurized milk, respectively. Coliform counts greater than 4.70 and 1.0 log10cfu/ml for raw and pasteurized milk were detected in 77.8% and 4.8%, respectively of raw and pasteurized milk samples collected. Enterobacteriaceae and S. aureus were detected with mean counts ranging from 6.08-6.86 and 5.82-6.32 log10/ml, respectively. Highest mean acidity and counts were recorded from slum areas of Nairobi and there were significant differences between raw and pasteurized milk (P < 0.05). The poor bacterial quality coupled with high acidity of raw milk, indicates poor hygienic practices and lack of temperature control during marketing. The incidence of high acidity and bacterial counts in pasteurized milk could indicate post process contamination and/or inappropriate storage of the milk. Most vendors of pasteurized milk were observed selling directly from the distributor crates without refrigerated storage. The rapid deterioration of raw and pasteurized milk marketed in Nairobi, at the time of this study, may be largely due to poor hygienic standards and non-adherence to temperature controls during handling, distribution and marketing. This requires urgent attention by the appropriate authorities, because the poor microbiological quality of raw milk and pasteurized milk may expose consumers to health risks associated with the consumption of contaminated milk.


Onyango C.,Kenya Industrial Research and Development Institute | Mutungi C.,TU Dresden | Unbehend G.,Institute For Sicherheit Und Qualitat Bei Getreide | Lindhauer M.G.,Institute For Sicherheit Und Qualitat Bei Getreide
LWT - Food Science and Technology | Year: 2011

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. © 2010 Elsevier Ltd.


Onyango C.,Kenya Industrial Research and Development Institute | Mutungi C.,TU Dresden | Unbehend G.,Institute For Sicherheit Und Qualitat Bei Getreide | Lindhauer M.G.,Institute For Sicherheit Und Qualitat Bei Getreide
LWT - Food Science and Technology | Year: 2011

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-weight-basis, 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. Sorghum-based 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. © 2010 Elsevier Ltd.


Onyango C.,Kenya Industrial Research and Development Institute | Mutungi C.,TU Dresden | Unbehend G.,Institute For Sicherheit Und Qualitat Bei Getreide | Lindhauer M.G.,Institute For Sicherheit Und Qualitat Bei Getreide
International Journal of Food Science and Technology | Year: 2010

The influence of α-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. © 2010 The Authors. Journal compilation © 2010 Institute of Food Science and Technology.


Musieba F.,Kenya Industrial Research and Development Institute | Okoth S.,University of Nairobi | Mibey R.K.,Moi University | Wanjiku S.,Kenya Industrial Research and Development Institute | Moraa K.,Kenya Industrial Research and Development Institute
American Journal of Food Technology | Year: 2013

There are many species of indigenous mushrooms in Kenya which form part of the traditional food system but whose nutritional and cultivation studies have not been completely determined and hence under utilized. The indigenous P. citrinopileatus was collected from Kakamega forest in Western Kenya, characterized and grown at the Kenya Industrial Research and Development Institute laboratories. The objective of this study was to evaluate indigenous P. citrinopileatus mushroom with the aim of qualifying and quantifying chemical information that might serve as a guide to exploit its potentials and benefits for human nutrition. The proximate composition (moisture, energy, fibre, crude fat, ash, minerals and protein) and amino acids contents (by high performance liquid chromatography) and vitamins of the indigenous P. citrinopileatus mushroom were determined. Proximate analysis of P. citrinopileatus revealed that it contained 22.10% protein, 1.32% crude lipid and 20.78% fibre. The mushroom was also found to contain variable amounts of minerals. The most predominant mineral found in the mushroom was Potassium with value of 2.28%. Copper, zinc and iron minerals were generally low with values from 0.0002, 0.0015 and 0.01%, respectively. Eight essential amino acids were detected namely Leucine>Valine> Threonine>Lysine>Phenylalanine>Isoleucine>Methionine>Tryptophan in decreasing order of abundance. Glutamic acid though non-essential was present in high proportion (3.07%). Vitamin B3 (Nicotinic acid), vitamin B5 (Pantothenic acid) and vitamin B2 (Riboflavin) were the most abundant vitamins in all samples analyzed. While vitamin B12 (Cyanocobalamin) and vitamin A (retinol) were the least with values of 0.3 and <10 μg/100 g, respectively. In conclusion, Pleurotus citrinopileatus mushroom can be an excellent source of micronutrients and antioxidants components. © 2013 Academic Journals Inc.


Kuria A.,University of Nairobi | Ombui J.,University of Nairobi | Onyuka A.,Kenya Industrial Research and Development Institute
Journal of the Society of Leather Technologists and Chemists | Year: 2016

Due to stringent environmental regulation concerning the disposal of tannery waste products there is continuous research on discovering eco-friendly tanning reagents. Vegetable tannins are less polluting to the environment than chromium. Astudy has been conducted to evaluate the tannin content and tanning strength of selected vegetable tanning materials found in Laikipia County and their suitability for tanning hides and skins. The hide powder method was used in determining the amounts of tannins. Acacia nilotica, Acacia xanthophloea and Hagenia abyssinica had percentage tannins of 16.8%, 23.8%, 11.73% respectively and all of them had a tanning strength of more than 1.5.


Mutungi C.,TU Dresden | Schuldt S.,TU Dresden | Onyango C.,Kenya Industrial Research and Development Institute | Schneider Y.,TU Dresden | And 2 more authors.
Biomacromolecules | Year: 2011

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. © 2011 American Chemical Society.


Mutungi C.,TU Dresden | Passauer L.,TU Dresden | Onyango C.,Kenya Industrial Research and Development Institute | Jaros D.,TU Dresden | Rohm H.,TU Dresden
Carbohydrate Polymers | Year: 2012

Because starch crystallinity influences the physical, mechanical, and technological aspects of numerous starch-based products during production and storage, rapid techniques for its assessment are vital. Samples of different levels of crystallinity were obtained by debranching gelatinized cassava starch, followed by subjection to various hydrothermal treatments. The recrystallized products were further subjected to partial hydrolysis with a mixture of α-amylase and glucoamylase prior to freeze-drying. Crystallinities were determined using X-ray diffraction (XRD) and 13C CP/MAS NMR spectroscopy, and correlated with FT-Raman spectra features. XRD crystallinities ranged between 0 and 58%, and agreed with crystalline-phase fractions (R 2 = 0.99) derived from the respective 13C CP/MAS NMR spectra. A strong linear correlation was found between crystallinities and integrated areas of the skeletal mode Raman band at 480 cm-1 (R 2 = 0.99). With appropriate calibration, FT-Raman spectroscopy is a promising tool for rapid determination of starch crystallinity. © 2011 Elsevier Ltd. All Rights Reserved.


Onyuka A.S.,Kenya Industrial Research and Development Institute
XXXIII IULTCS Congress | Year: 2015

The leather industry in Kenya contributes about 4 percent of the agricultural GDP and 1.5 percent of overall GDP. Currently, there are 13 commercial tanneries offering employment to about 1500 people. The tanneries mainly process wet salted raw hides and skins to wet blue for export. Occupational Safety and Health (OSH) has been a major concern to the industry stakeholders. The aim of this study was to assess the occupational safety and health management and practices in the tanneries and the extent to which they are aligned to the legislation and overall Occupational Safety and Health requirements. The study undertaken in 8 of the tanneries involved site visit to examine practices, governance and structures established to achieve and maintain the required Occupational Safety and Health as it relates to safe operations and the work environment. Within the scope of the assessment the study found that the general Occupational Safety and Health (OSH) practices in the tanneries does not meet the requirements and need urgent improvement. Those areas requiring urgent improvement include; formulation of policies, mandatory OSH awareness and training for the management, supervisors and workers, information system on workplace hazardous materials and practices, establishment of internal monitoring and performance measures for the management to more effectively evaluate the performance of the OSH measures in place. This study has provided the current status of the OSH in the leather industry in Kenya and forms the basis for addressing the training needs in the sector including regulatory interventions from the relevant government agencies.


Onyango C.,Kenya Industrial Research and Development Institute | Mutungi C.,TU Dresden | Unbehend G.,Max Rubner Institute | Lindhauer M.G.,Max Rubner Institute
Journal of Food Engineering | Year: 2010

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. © 2009 Elsevier Ltd. All rights reserved.

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