Dennis Maina Gatahi; Felix Nyoro
Abstract
Fresh Moringa oleifera leaves are very rich in phytonutrients, however the leaves are also highly perishable and require processing for increased shelf-life. The method of processing, specifically drying affects the nutritional value of the product. The present study therefore, analyzed the nutraceutical ...
Read More
Fresh Moringa oleifera leaves are very rich in phytonutrients, however the leaves are also highly perishable and require processing for increased shelf-life. The method of processing, specifically drying affects the nutritional value of the product. The present study therefore, analyzed the nutraceutical value and growth of toxic microbes when the leaves were dried under different conditions i.e. room temperature, greenhouse, 50% shade net, and in the oven at 60 oC for 4 h. The experiments were carried out at the Jomo Kenyatta University of Agriculture and Technology (JKUAT). The treatments were applied in triplicate and arranged on a completely randomized design (CRD). Data on nutritional value of dried Moringa leaves was subjected to analysis of variance (ANOVA) for parameterization and means separated using protected LSD0.05. The study showed that drying Moringa leaves under shade, room and greenhouse conditions significantly (P<0.05) affects the nutritional value of the product. The results showed highest levels of vitamin C, vitamin A, polyphenols and terpenoids when the leaves were dried under 50% shade net and room temperature conditions. In contrast, the glucosinolate content was significantly (P<0.05) higher when the leaves were dried instantly in the oven (9.1%/wt), followed by drying under greenhouse conditions (8.7%/wt) before oven drying. However, drying of Moringa leaves under shade before oven drying resulted in growth of toxic microbial organisms such as staphylococcus, yeast, E. coli and molds that can potentially affect the safety of the product. Finally, the drying conditions also significantly (P<0.05) affected the moisture content of the powder obtained. The results of this study form an important reference for small-holder Moringa growers and processors in the development of an optimal processing regime for high value Moringa powder.
Dennis Maina Gatahi
Abstract
Tomato (Lycopersicon esculentum) is an important member of the Solanaceae family. It is mainly used as food and cash crop globally. Tomato also serves as an ornamental plant in some parts of the world. In urban areas, this crop is included in the foodscaping systems where it is grown in hanging baskets, ...
Read More
Tomato (Lycopersicon esculentum) is an important member of the Solanaceae family. It is mainly used as food and cash crop globally. Tomato also serves as an ornamental plant in some parts of the world. In urban areas, this crop is included in the foodscaping systems where it is grown in hanging baskets, growing pots and aquaponics for aesthetic and food purposes. Tomato production is mainly done for fresh and processing market niches. Most developed countries process a larger portion of tomato than is offered in fresh form. Cultivation of tomato is practiced on the open field and inside greenhouses. Greenhouse production has gained popularity recently. Determinate varieties are produced outdoor while indeterminate ones are produced in greenhouses and tunnels. Due to good adaptability, heirloom tomato varieties are becoming popular especially where farmers practice tomato grafting using the indigenous varieties as rootstocks. High cost of inputs, pest and diseases, postharvest losses and marketing are the major challenges facing tomato production globally. Organic tomato production is an emerging market niche. This is due to the increased consumer awareness, environmental conservation requirements and globalization. Thus, farmers have been making strides towards compliance to organic and other sustainable standards. These standards require adoption of the requisite practices, documentation, verification and certification by a third party. Value addition in tomato is an important aspect in addressing the postharvest challenges, product diversification and ultimately profitability. This review paper is expected to provide the requisite information in tomato value chain to ensure sustainable production of tomato globally.
Dennis Maina Gatahi; Harrison Njuma Wanyika; Agnes Kavoo; Agnes Kihurani; Elijah Miinda Ateka
Abstract
Biological control agents are useful components in the enhancement of plant disease resistance and improvement of soil properties. Effect of biological control agents (BCAs) as a disease control method in plants is hampered by their vulnerability to environmental and edaphic conditions. This study entailed ...
Read More
Biological control agents are useful components in the enhancement of plant disease resistance and improvement of soil properties. Effect of biological control agents (BCAs) as a disease control method in plants is hampered by their vulnerability to environmental and edaphic conditions. This study entailed the use of chitosan-silica nanocomposites for delivery of BCAs. Effect of BCAs-nanocomposite complexes (bionanocomposites) on resistance of tomato plants to bacterial wilt, mycorrhizal root colonization and rhizosphere soil properties were investigated. Replacement of mesoporous silica nanoparticles (MSN) in the nanocomposite with nano synthesized clay was also assessed on disease resistance. Tomato seeds and seedlings were pre-treated using bionanocomposites and then inoculated by Ralstonia solanacearum isolated from infected tomato plants in a greenhouse. Bionanocomposites treatment of tomato plants caused a significant increase (P≤0.05) in the level of pathogenesis-related biochemicals such as chitinase and glucanase. Furthermore, beneficial microbial colonization was significantly (P≤0.05) induced in roots treated with the bionanocomposites. Wilting incidence and symptoms were reduced by over 50% when bionanocomposites were used. There was no significant effect (P≤0.05) on induced host plant resistance when mesoporous silica nanoparticles (MSN) were substituted with nanoclay particles. Therefore, due to ease of availability with no significant (P≤0.05) difference in efficacy between the nanoparticles, replacement of MSN with nanoclay in synthesis of the bionanocomposites is recommended. We argue that substitution of nanoclay with MSN makes the process of synthesizing the bionanocomposites sustainable.
