Chapter 13 from Using Food Science and Technology to Improve Nutrition and Promote National Development, 2008
The purpose of traditional food processing is preservation to maintain a supply of wholesome, nut... more The purpose of traditional food processing is preservation to maintain a supply of wholesome, nutritious food during the year and preservation for the time of scarcity. While food processing still has the main objective of providing a safe nutritious diet in order to maintain health, other aspects, particularly the generation of wealth for the producer and seller, have become increasingly important. While most people in the rural areas still rely on traditional foods for their basic diet, those in urban and cosmopolitan centers tend to purchase processed and packaged foods for convenience. The increasing number of women who now work away from home adds additional pressure for such changes. Even people with a heavily traditional diet are demanding external products either as occasional treats such as gassy drinks, or basic commodities such as white sugar and flour. Although over 60% of the Kenyan populace lives below the poverty line resulting in malnutrition, poor health and inadequate basic necessities, Kenya is endowed with agrobiodiversity such as African Indigenous Vegetables (AIVs) that are highly nutritious, have health benefits, income generation potential and agronomic advantages that need exploiting. Research carried out at Maseno University in 2008 had the aim of developing East African indigenous vegetable recipes in order to promote utilization of AIVs for micronutrient malnutrition alleviation. East African indigenous vegetable products were developed which could contribute to poverty reduction and ensure availability of these vegetables during off-seasons even in supermarkets in Kenya. This technology should be further developed and disseminated to the community to address food insecurity.
The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a key insect pest of am... more The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a key insect pest of amaranth in East Africa. Pest management has been restricted to indiscriminate application of insecticides to foliage. Applying systemic insecticides to seeds has been shown to manage aphid infestations in other crop systems. We evaluated two commercially available seed treatments in East Africa, Apron Star (thiamethoxam 20 g/kg + metalaxyl-M 20 g/kg + difenoconazole 2 g/kg) and Menceron (imidacloprid 233 g/L + pencycuron 50 g/L + thiram 107 g/L) for their efficacy against M. persicae and impact on fresh leaf yield with two Amaranthus species, Amaranthus blitum (2 selections), Amaranthus hybridus (4 selections) and untreated control. Two storage periods (24 h and 3 months) with seed treatments were used. Each amaranth selection was treated individually with Apron and Monceren or untreated, and seeds were planted either 24 h or 3 months after treatment. Significant reduction in live aphids was observed with A. blitum and A. hybridus selections grown with seed treatment, at 6, 8 and 10 d after infestation (DAI) when compared with seeds grown without seed treatment. Untreated seeds of A. hybridus (selection 5) had significantly higher number of live aphids up to 243, greater percentage of damaged leaves and leaf damage score up to 84% and 64% respectively when compared with treated seeds of specific amaranth at 10 DAI. No significant difference was noted between seed treatment and storage time. Amaranth seeds treated with Monceren offered more protection against infestations of Myzus persicae than amaranth seeds treated with Apron under high tunnel experiments.
Spiderplant is an important African Indigenous Vegetable especially in Kenya with its popularity ... more Spiderplant is an important African Indigenous Vegetable especially in Kenya with its popularity fast spreading due to its nutritional and medicinal values. Optimum stand establishment and maximum yield potential of spiderplant is majorly determined by the quality of seed. Physical and physiological seed quality components are used in seed testing. The physical purity and percentage germination are some of the most influential aspects. Most farmers depend heavily on ‘farmer-saved’ seeds which are of low quality due to seed handling and storage. The aim of this study was to determine the percentage purity and percentage germination of Spiderplant accessions from various regions of Kenya. Surveys were conducted to collect germplasm from Western Kenya. A total of 35 accessions were collected from farmers and 5 accessions from AVRDC. A purity test was conducted to establish the fraction of pure seed. A sample of seeds with impurities was weighed, and then the two fractions were separate...
... For example, the majority of farmers in the East African region grow AIVs mainly at a subsist... more ... For example, the majority of farmers in the East African region grow AIVs mainly at a subsistence rain-fed production level (Nekesa and Meso, 1997) with leaf yields of 1 to 2 tonnes per hectare (t/ha) against a documented potential of 40t/ha (Abukutsa-Onyango, 2003). ...
African nightshade (Solanum scabrum ) is an important African Leafy Vegetable yet factors affecti... more African nightshade (Solanum scabrum ) is an important African Leafy Vegetable yet factors affecting leaf yields have not been fully investigated. The objective of the study was to investigate effects of nitrogen rates on growth and yield of African nightshades. A pot and two field experiments were conducted at Maseno University, Kenya. The pot experiment was laid out in randomised complete block design with four treatments and four replications. The treatments included 0, 2.5, 5.0 and 7.5 g of N per pot .(18cm diameter pot). The field experiments were set up in a randomised complete block design with 6 N rates and three replications. The treatments included 0, 10, 20, 40, 80 and 100 kg of N per hectare. Nitrogen levels significantly (pd”0.05) affected plant growth, and leaf yields in both pot and field experiments with optimal levels at 2.5 gN/pot and 40 kg N/ha respectively.
Kenya is confronted with a paradoxical situation of malnutrition: on the one hand hunger is still... more Kenya is confronted with a paradoxical situation of malnutrition: on the one hand hunger is still prevalent within the Kenyan society with 24% of the population being undernourished; on the other hand an increasing number of the population is suffering obesity and “hidden hunger”. In order to overcome malnutrition in Kenya recent studies emphasise the relevance of African indigenous vegetables (AIVs), which are nutrient rich and contain medicinal value. Although AIVs are an important component of households’ diets in Kenya, AIV consumption is still low. Thus, this paper aims at investigating the factors that influence consumption of AIVs in Kenyan households. This paper presents first research results of the HORTINLEA subproject “Meal Cultures in Market Trends and Consumption Habits”. The paper starts from the assumption that place-based practices of food production and preparation, symbolic meanings of food as well as social relations of power frame the consumption of food. Referri...
The green peach aphid [Myzus persicae (Sulzer)] is an important pest of amaranth grown for leaf c... more The green peach aphid [Myzus persicae (Sulzer)] is an important pest of amaranth grown for leaf consumption (i.e., leafy amaranth) in the tropics. Aphids reduce the amount of fresh leaf yield of amaranth and the value of leafy amaranth as aphid-infested leaves are not marketable. Our objective was to evaluate Amaranthus species selected by a breeding program in East Africa to develop cultivars for leaf consumption with resistance to M. persicae. We focused on antibiosis to determine whether varieties of Amaranthus spp. could be grown without producing an aphid population. Artificial infestations of aphids were placed on multiple selections of three species of Amaranthus: two selections of A. blitum, four selections of A. hybridus and one selection of A. hypochondriacus. Aphid populations were assessed over a 5-wk period. Evaluations of vegetative yield, leaf damage symptoms, and specific leaf area (SLA) were made of the seven selections at the end of this experiment. Aphid populatio...
Chapter 13 from Using Food Science and Technology to Improve Nutrition and Promote National Development, 2008
The purpose of traditional food processing is preservation to maintain a supply of wholesome, nut... more The purpose of traditional food processing is preservation to maintain a supply of wholesome, nutritious food during the year and preservation for the time of scarcity. While food processing still has the main objective of providing a safe nutritious diet in order to maintain health, other aspects, particularly the generation of wealth for the producer and seller, have become increasingly important. While most people in the rural areas still rely on traditional foods for their basic diet, those in urban and cosmopolitan centers tend to purchase processed and packaged foods for convenience. The increasing number of women who now work away from home adds additional pressure for such changes. Even people with a heavily traditional diet are demanding external products either as occasional treats such as gassy drinks, or basic commodities such as white sugar and flour. Although over 60% of the Kenyan populace lives below the poverty line resulting in malnutrition, poor health and inadequate basic necessities, Kenya is endowed with agrobiodiversity such as African Indigenous Vegetables (AIVs) that are highly nutritious, have health benefits, income generation potential and agronomic advantages that need exploiting. Research carried out at Maseno University in 2008 had the aim of developing East African indigenous vegetable recipes in order to promote utilization of AIVs for micronutrient malnutrition alleviation. East African indigenous vegetable products were developed which could contribute to poverty reduction and ensure availability of these vegetables during off-seasons even in supermarkets in Kenya. This technology should be further developed and disseminated to the community to address food insecurity.
The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a key insect pest of am... more The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a key insect pest of amaranth in East Africa. Pest management has been restricted to indiscriminate application of insecticides to foliage. Applying systemic insecticides to seeds has been shown to manage aphid infestations in other crop systems. We evaluated two commercially available seed treatments in East Africa, Apron Star (thiamethoxam 20 g/kg + metalaxyl-M 20 g/kg + difenoconazole 2 g/kg) and Menceron (imidacloprid 233 g/L + pencycuron 50 g/L + thiram 107 g/L) for their efficacy against M. persicae and impact on fresh leaf yield with two Amaranthus species, Amaranthus blitum (2 selections), Amaranthus hybridus (4 selections) and untreated control. Two storage periods (24 h and 3 months) with seed treatments were used. Each amaranth selection was treated individually with Apron and Monceren or untreated, and seeds were planted either 24 h or 3 months after treatment. Significant reduction in live aphids was observed with A. blitum and A. hybridus selections grown with seed treatment, at 6, 8 and 10 d after infestation (DAI) when compared with seeds grown without seed treatment. Untreated seeds of A. hybridus (selection 5) had significantly higher number of live aphids up to 243, greater percentage of damaged leaves and leaf damage score up to 84% and 64% respectively when compared with treated seeds of specific amaranth at 10 DAI. No significant difference was noted between seed treatment and storage time. Amaranth seeds treated with Monceren offered more protection against infestations of Myzus persicae than amaranth seeds treated with Apron under high tunnel experiments.
Spiderplant is an important African Indigenous Vegetable especially in Kenya with its popularity ... more Spiderplant is an important African Indigenous Vegetable especially in Kenya with its popularity fast spreading due to its nutritional and medicinal values. Optimum stand establishment and maximum yield potential of spiderplant is majorly determined by the quality of seed. Physical and physiological seed quality components are used in seed testing. The physical purity and percentage germination are some of the most influential aspects. Most farmers depend heavily on ‘farmer-saved’ seeds which are of low quality due to seed handling and storage. The aim of this study was to determine the percentage purity and percentage germination of Spiderplant accessions from various regions of Kenya. Surveys were conducted to collect germplasm from Western Kenya. A total of 35 accessions were collected from farmers and 5 accessions from AVRDC. A purity test was conducted to establish the fraction of pure seed. A sample of seeds with impurities was weighed, and then the two fractions were separate...
... For example, the majority of farmers in the East African region grow AIVs mainly at a subsist... more ... For example, the majority of farmers in the East African region grow AIVs mainly at a subsistence rain-fed production level (Nekesa and Meso, 1997) with leaf yields of 1 to 2 tonnes per hectare (t/ha) against a documented potential of 40t/ha (Abukutsa-Onyango, 2003). ...
African nightshade (Solanum scabrum ) is an important African Leafy Vegetable yet factors affecti... more African nightshade (Solanum scabrum ) is an important African Leafy Vegetable yet factors affecting leaf yields have not been fully investigated. The objective of the study was to investigate effects of nitrogen rates on growth and yield of African nightshades. A pot and two field experiments were conducted at Maseno University, Kenya. The pot experiment was laid out in randomised complete block design with four treatments and four replications. The treatments included 0, 2.5, 5.0 and 7.5 g of N per pot .(18cm diameter pot). The field experiments were set up in a randomised complete block design with 6 N rates and three replications. The treatments included 0, 10, 20, 40, 80 and 100 kg of N per hectare. Nitrogen levels significantly (pd”0.05) affected plant growth, and leaf yields in both pot and field experiments with optimal levels at 2.5 gN/pot and 40 kg N/ha respectively.
Kenya is confronted with a paradoxical situation of malnutrition: on the one hand hunger is still... more Kenya is confronted with a paradoxical situation of malnutrition: on the one hand hunger is still prevalent within the Kenyan society with 24% of the population being undernourished; on the other hand an increasing number of the population is suffering obesity and “hidden hunger”. In order to overcome malnutrition in Kenya recent studies emphasise the relevance of African indigenous vegetables (AIVs), which are nutrient rich and contain medicinal value. Although AIVs are an important component of households’ diets in Kenya, AIV consumption is still low. Thus, this paper aims at investigating the factors that influence consumption of AIVs in Kenyan households. This paper presents first research results of the HORTINLEA subproject “Meal Cultures in Market Trends and Consumption Habits”. The paper starts from the assumption that place-based practices of food production and preparation, symbolic meanings of food as well as social relations of power frame the consumption of food. Referri...
The green peach aphid [Myzus persicae (Sulzer)] is an important pest of amaranth grown for leaf c... more The green peach aphid [Myzus persicae (Sulzer)] is an important pest of amaranth grown for leaf consumption (i.e., leafy amaranth) in the tropics. Aphids reduce the amount of fresh leaf yield of amaranth and the value of leafy amaranth as aphid-infested leaves are not marketable. Our objective was to evaluate Amaranthus species selected by a breeding program in East Africa to develop cultivars for leaf consumption with resistance to M. persicae. We focused on antibiosis to determine whether varieties of Amaranthus spp. could be grown without producing an aphid population. Artificial infestations of aphids were placed on multiple selections of three species of Amaranthus: two selections of A. blitum, four selections of A. hybridus and one selection of A. hypochondriacus. Aphid populations were assessed over a 5-wk period. Evaluations of vegetative yield, leaf damage symptoms, and specific leaf area (SLA) were made of the seven selections at the end of this experiment. Aphid populatio...
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