Michael Okoth

Michael Okoth
University of Nairobi | UON · Department of Food Science, Nutrition and Technology

B.Sc. (Eng), M.Sc. (FST), PhD

About

108
Publications
58,393
Reads
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1,208
Citations
Additional affiliations
February 1985 - present
University of Nairobi
Position
  • Associate Dean/Associate Professor
Description
  • Teaching Food Engineering/Food Technology. I have supervised many M.Sc. and PhD students. Research includes energy use in food processing, process and product development, optimization of processing plants.
February 1985 - present
University of Nairobi
Position
  • Academic Staff
Description
  • I am currently an Associate Professor teaching Food Engineering and Food Technology courses
Education
August 1985 - December 1989
Swiss Federal Institute of Technology, Zurich (ETH Zurich)
Field of study
  • Food Process Engineering
April 1982 - July 1984
University of Nairobi
Field of study
  • Food Science and Technology
September 1975 - June 1978
Imperial College, University of London
Field of study
  • Chemical Engineering

Publications

Publications (108)
Article
Full-text available
Coffee is one of the most consumed beverages across the world with increasing demand in non- traditional markets due to its unique sensory and physiological characteristics. However, coffee has been found to have accumulated acrylamides which are carcinogenic and may end up intoxicating consumers. The degree of roasting determines the quality chara...
Article
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Cost-effective techniques are usually recommended in the dissemination and adoption of postharvest processing technologies of food products. Due to limited value addition practices for cowpea leaf, the Fruits and Vegetables for All Seasons Project undertook a study to bridge the gap in the seasonal availability of the vegetable in the arid and semi...
Poster
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Field production of potato involves intensive pesticide use but farmers and consumers are uninformed about pesticides used or the risks involved in misappropriate application. Potato is processed into snacks such as crisps which are a loved and consumed by all ages. Potato variety that is used mainly for processing into crisps is Dutch Robyjn, grow...
Article
Although fruit pulping is a highly effective global practice for ensuring a steady supply of fruit for processing during the offseason, industrial pulping of Kenyan guava cultivars is lacking, contributing to their annual losses. The present study compared the yield characteristics, physicochemical profile, and nutrient retention of pulp extracted...
Article
Full-text available
A bean‐based composite soup flour (CSF) containing red kidney beans, sweet potatoes, amaranth leaves, and carrots was developed using Nutrisurvey software to choose four nutritious CSFs, which were then subjected to sensory evaluation to select the most preferred CSF by mothers with young children. The top‐ranked bean‐based CSF was then analyzed fo...
Article
Whole grain flour is gaining an increase in demand for its nutritive and health promotion values in different food products for human consumption worldwide. Whole flour from wheat grain varieties (Gihundo, Kibatsi, Nyaruka and Reberaho), spent coffee grounds (SCG), juices of lemon fruit (L) and rosemary leaves (R), and dough fermentation were asses...
Article
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Background As much as local communities have employed traditional techniques of preservation to enhance availability and utilization of cowpea leaves, the efficiency of these techniques in achieving food security need to be established. The current study sought to document trends and constraints of utilization of preserved cowpea leaves in the arid...
Article
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Despite the critical role of cowpea leaves in the ASAL as a food security crop, drought, diseases and pests remain major challenges to be addressed. Prioritizing alternative water sources and extension services is recommended. The gender of a household head influences the use of cowpeas leaves in the ASAL. There is need for food security initiativ...
Article
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Efforts of improving food and nutrition security which is one of the Big Four Agenda of the Kenyan Government are constrained by the massive postharvest losses evidenced in various value chains. Whereas the set target of reducing postharvest losses (PHL) from 20% to 15% in the dominant value chains of cereals by 2022 still remains on course, Gogo e...
Article
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Cassava roots, millet and cowpea leaves have short storage life thus the need for simple post-harvest handling and storage protocol to ensure prolonged availability to fully contribute toward food and nutrition security, a major challenge within Sub-Saharan Africa. The current study sought to investigate the effect of pre-treatment and processing o...
Article
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No data exist on the nutrient composition of some important Rwandan staples. The aim of this study was to evaluate the nutrient content of red kidney beans, sweet potato roots, amaranth leaves and carrot roots. About 6 kg of each raw material were cleaned and conditioned prior to mechanical drying, ground and sieved [60-mesh] into flour and then su...
Article
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The quality and shelf life of French beans is affected by the time of harvesting and storage period. Cooling immediately after harvesting is important. Use of solar evaporative cooling system is suitable for use in rural areas with no power grid connections. This study compared evaporative charcoal cooler and the solar cooling systems on improving...
Article
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p>The present study aimed to evaluate the effect of the wheat varieties newly introduced in Rwanda on the physicochemical characteristics of their whole wheat grains in order to know their potentials for processing. Gihundo wheat grain variety had the highest values for extraction yield (99.20 %), contents of ash (1.47 %) and total dietary fiber (1...
Article
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Malnutrition, hunger, and poverty are still major challenges globally especially in Sub-Saharan Africa affecting most countries like Nigeria. Legumes play key roles in food and nutritional security, health, and income generation. This review highlights status of pulse production and consumption in Nigeria and need for improvement. The study involve...
Article
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In as much as spontaneous fermentation of cowpea leaves enhances product diversification, the process is rather slow with poor product quality. Limited work has been undertaken to provide input toward standardization of the process and enhancing of product quality. The current study sought to evaluate the in‐process fermentative bacteria profile ch...
Article
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Phytochemicals enhance human health by acting antagonistically on incidences of cancer and other chronic diseases. They are considered indispensable in a variety of nutraceutical, pharmaceuticals, and medicinal and cosmetic applications. This study evaluated the effects of common processing methods on inherent phytochemical content in the roots and...
Article
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The levels of acrylamide intake because of potato crisps consumption remains unknown in Kenyan context. This study assessed the exposure to acrylamide because of consumption of potato crisps in Nairobi, Kenya. A cross-sectional survey was carried out among 315 crisps consumers in Nairobi, and consumption patterns were collected using a pre-tested s...
Article
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With the ever-increasing intake and diversification of bread in sub-Saharan Africa, greater risks of food fraud are posed. The risks are even higher in the urban areas where both the formal and informal retail exist. Product diversification induced by incorporation of different ingredients in bread processing aggravates the risk of malpractices in...
Article
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A majority of households in Sub-Saharan Africa utilize cereal-based flours in the preparation of most of their staples. However, the micronutrient contents of these cereal-based flours are low with higher levels of anti-nutrients. Food to food fortification is being used as an alternative to improve the micronutrient content of the cereal-based flo...
Article
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The guava fruit is a highly palatable and nutritious tropical fruit with a pleasant flavor. It is abundant at moderate prices in Kenya. However, limited processing and poor market returns result in high annual losses of the fruits. This study aimed at assessing the production, utilization, preservation and processing of guavas in Kitui and Taita Ta...
Article
Full-text available
Cowpea (Vigna unguiculata) leaves are nutritious indigenous vegetables that are produced and consumed among local communities in Kenya. However, seasonal production limits their utilization. The study investigated the changing trends in the consumption and utilization of cowpea leaves among cowpea producing households in arid and semi-arid land (AS...
Article
Full-text available
Background: Glycoalkaloids are naturally occurring toxins in potatoes which, at high levels, pose food safety concerns to consumers. Their concentrations in potatoes are dependent on postharvest handling, variety and stress factors tubers are exposed to. Limited information, however, exists on levels of glycoalkaloids in commercially traded potato...
Article
Full-text available
Background: Glycoalkaloids are naturally occurring toxins in potatoes which, at high levels, pose food safety concerns to consumers. Their concentrations in potatoes are dependent on postharvest handling, variety and stress factors tubers are exposed to. Limited information, however, exists on levels of glycoalkaloids in commercially traded potato...
Article
Full-text available
There is global increase in demand for good health and nutrition. The objective of this study was to formulate nutritious composite flours from cassava (Manihot esculenta L.) roots, cowpea (Vigna unguiculata) leaves, and millet (Pennisetum glaucum), especially for children and expectant women. A Nutrisurvey software was used to formulate three flou...
Article
Full-text available
This study reports the inherent phytochemical contents in leaves and roots of nine sweet potato varieties from Kenya. Results indicated that vitamin C content varied significantly ( P<0.05 ) among the sweet potato varieties regardless of the plant part, leaves having significantly ( P<0.05 ) higher levels than in the roots. Total flavonoids and phe...
Article
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The guava (Psidium guajava L.) tree is extensively grown in the tropical and sub-tropical regions of the world. It is quite resilient, highly productive, has high economic returns and requires minimal care. The fruit is very nutritious with a characteristic flavor and has a high demand internationally especially when processed into pulp, concentrat...
Article
Full-text available
Tomato consumed worldwide for its vitamins and bioactive elements can harbor postharvest bacteria and pesticide residues. A cross-sectional survey using a semi-structured questionnaire was done in 101 households in Kangemi assessing consumers’ awareness on pesticide residues and bacterial presence on tomatoes sold in Nairobi. Questionnaire was admi...
Article
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Abstract Cowpea leaf is among the African indigenous vegetables that have been recommended for possible alleviation of food and nutrition insecurity in sub-Saharan Africa (SSA). The vegetable is rich in micronutrients including iron and vitamin A whose deficiencies are prevalent in SSA. Considering the limitation of seasonal availability, preservat...
Article
The study sought to evaluate shelf-storable OFSP puree as a possible alternative to fresh OFSP puree in bread baking. The physico-chemical attributes of the breads in which two treatments of shelf-storable OFSP puree, T1 and T2 with 0.5% potassium sorbate +0.5% sodium benzoate +1% citric acid and 0.2% potassium sorbate +0.2% sodium benzoate +1% cit...
Article
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The influence of milk flow rate and inlet drying air temperature on the physical, optical and thermal properties of laboratory spray-dried camel milk powders is investigated. The physical, thermal and optical properties of laboratory spray-dried camel milk powders at three inlet drying air temperatures (110, 120 and 130 °C) and two milk flow rates...
Article
Full-text available
Postharvest handling of the potato is an important factor not only in preventing postharvest losses but also in maintaining its safety and nutritional quality. Exposure of the potato to unfavorable conditions such as light, extreme temperatures, and bruising can result in accumulation of glycoalkaloids, which are toxic substances. This study was a...
Article
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Most of the products of maize flour fermentation in Kenya undergo wild fermentation in a natural process. One of these is locally roasted maize flour commonly known by its local name Mkarango which is popular in the Western region of Kenya where it is used in different ways. Mkarango is mostly made through wild fermentation which is known to pose h...
Article
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Meat is an important dietary component of the pastoral communities living in marginalized regions of Kenya. Indigenous meat processing, in particular koche processing, plays a significant role in the economic and social life of the Borana community. It contributes to animal-source protein as well as income generation as a livelihood activity by the...
Article
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Bread though an exotic food product in sub-Saharan Africa, has been an important cereal product consumed by most individuals among the vast Sub-Saharan African population. Bread formulations in both the local and industrial production have evolved. The latest and emerging technology in bread formulation involve the incorporation of orange-fleshed s...
Article
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Technological advances in baking have enabled the use of bread as a food vehicle for various nutrients through use of composite flours. Orange-fleshed sweetpotato (OFSP) puree subjected to cold chain storage has been used to enrich bread with beta-carotene. However, this has proven expensive and inconsistent in supply of puree. This study sought to...
Poster
Full-text available
The Hidden Poison in Potato and Potato Products: Glycoalkaloids - Poster
Article
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The objective of the present study was to determine the drying kinetics, moisture diffusivity and sensory quality of convective air dried beef. The effect of temperature of drying (30-60°C) and thickness of samples (2.5-10 mm) on the convective thin-layer drying kinetics of beef dried in a cabinet dryer was evaluated. Five semi-theoretical models w...
Article
Full-text available
In most parts of Africa, the process of fermentation is not controlled and does not adhere to good manufacturing practices, therefore spoilage and pathogenic microorganisms can alter the quality of the end product and may cause foodborne illness. Traditional fermented products are mostly processed in an environment which creates a selection of micr...
Article
Full-text available
Water security and safety is of vital concern in arid and semiarid regions of Kenya. Potable water accessibility and supply is limited due to fluctuating climatic conditions and environmental pollution that lower the wholesomeness of most water sources. The aim of this study was to establish the suitability of these water sources for drinking and u...
Article
The aim of this study was to investigate the influence of cabinet drying air temperature (30–60 °C) and sample thickness (2.5–10 mm) on the quality attributes of dried beef. The physical (colour, rehydration ratio/RR and texture) and microbial quality of beef samples were evaluated using standard procedures. There was a significant decrease (P ≤ 0....
Article
Full-text available
Current cultivation of vegetables to meet food security standards requires the use of pesticides which reduce losses from pests and diseases. A cross-sectional survey for pesticides use in tomato farms was conducted in Mwea, Kenya to assess the practices and constraints faced by the farmers. Gender, level of education, the use of pesticides in farm...
Article
Full-text available
Post-harvest handling of French beans is very critical in ensuring acceptable quality in the market. The time of harvesting and duration between harvesting and cooling are very important. Further, long distances between growing fields and cooling facilities provide challenges to growers. This study was carried out to evaluate the effects of harvest...
Article
Full-text available
French bean is a major export crop from Kenya into United Kingdom and Europe. It is usually consumed cooked. Food safety is one of the most important factors that influence success of fresh produce export. Microbial contamination is one of the food safety concerns in fresh produce industry. This study focused on understanding the correlation betwee...
Article
Full-text available
Post-harvest losses is still a common challenge in most African countries. At the Kenyan coast, farmers are faced with the challenge of handling cassava produce due to the short shelf-life of the product. Due to inadequate knowledge by the farmers and the low capacity building with regards to cassava production, utilisation and commercialisation th...
Article
Full-text available
Resistant starch is known to impart a number of health benefits to consumers. It is therefore desirable to increase the content of resistant starch inpopular foods such as yoghurt. Thecurrent research investigated the effect of cassava resistant starch synthesized by heat-moisture treatment of starch from I92/0057 cassava variety onphysico-chemical...
Article
Full-text available
This study determined the seasonal fluctuations in camel milk yield, consumption, spoilage and spillages, and explored its forms of consumption and the acceptability of camel milk powder in Isiolo County, Kenya. In addition, the utilization of non-marketed milk, preservation technologies, and strategies for milk loss reduction employed along the ca...
Article
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This study investigates current knowledge and performance of existing technology, ‘charcoal coolers’ in improving the overall quality and shelf-life of French beans. Data was collected primarily from a household survey using a semi-structured questionnaire administered to 45 purposively selected farmers who were selected at fixed interval. Data was...
Article
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Sweetpotato (Ipomea batatas) is a versatile crop that serves the roles of food and nutrition security, cash crop in both raw and processed forms. It is a source of livestock feed and has great potential as a raw material for industrial processing. The potential of sweetpotato has been greatly underexploited by the fact that it has been regarded as...
Article
Full-text available
Cassava forms part of diets in Kenya with both the roots and leaves being consumed as food. The short shelf-life of 72 hours and cyanogenic glucosides limit the extent of utilization. Currently, fried cassava chips and crisps are increasingly being consumed as snacks; and fried cassava chips are produced by street processors. The quality and safety...