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Recently, tannins have received considerable attention as health-promoting component in various plant foods and several studies have reported on its nutraceutical properties. However, no study has established the role of condensed tannins in indigenous foods of Kenya. Therefore, this study was designed to evaluate the antioxidant activity (DPPH and FRAP) and antidiabetic effects (α-amylase and α-glucosidase inhibition activities) of condensed tannins in some selected raw and traditionally processed indigenous cereals, legumes, oil seeds, and vegetables. The condensed tannin content of the grains and vegetables ranged between 2.55 and 4.35 g/100 g DM and 1.53 and 5.73 g/100 g DM, respectively. The scavenging effect of acetonic extract on DPPH radical ranged from 77% to 90% while the reducing power was found to be 31 to 574 mmol Fe(II)/g DM in all the investigated food ingredients. The condensed tannin extracts of the analyzed samples showed promising antidiabetic effects with potential α-amylase and α-glucosidase inhibition activities of 23% to 44% and 58% to 88%, respectively. Condensed tannins extracted from the amaranth grain, finger millet, field bean, sunflower seeds, drumstick, and amaranth leaves exerted significantly higher antioxidant and antidiabetic activities than other food ingredients. Among the traditional processing methods, roasting of grains and cooking of vegetables were found to be more suitable mild treatments for preserving the tannin compound and its functional properties as opposed to soaking + cooking and blanching treatments. The identified elite sources of optimally processed indigenous food ingredients with promising results could be used as health-promoting ingredients through formulation of therapeutic diets.

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, preservation techniques have been adopted to enhance availability with little success. This review aims at highlighting the contribution of cowpeas leaves to food and nutrition security as well as research gaps that must be addressed to promote the utilization of value‐added forms that would have extended effect of improving its production and consumption. It was found that preserved and fresh cowpea leaves were rich in beta‐carotene and iron in the ranges of 0.25–36.55 and 0.17–75.00 mg/100 g dry weight, respectively. The proportion of rural households incorporating the vegetable in its various forms in the region can be as high as 30%. With adequate utilization, the vegetable provided up to ≥ 75% and 25% of RDAs for vitamin A and iron, respectively, of children aged 4–8. However, the utilization of preserved forms faced a limitation for a deviation of up to 30% in their sensory scores and decreased nutrient content as compared to the fresh ones hugely hindered their market penetration. Utilization of novel processing techniques incorporating concept of hurdle technology can help address these quality losses. In conclusion, preservation of cowpea leaves should seek not only to enhance the shelf‐life, but also to enhance acceptability of the products with a view of increased utilization.

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There has been increasing consumption of potato products such as French fries and crisps in most countries as a result of lifestyle change in both developed and developing countries. Due to their generally pleasurable taste and texture, they are appreciated by a high number of consumers across the world, with the younger members of the population mostly those in the urban areas having a higher preference. The hard economic situations have also driven many people to their consumption as they are affordable. Moreover, these products are convenient for the younger generation who do not prepare their own food. However, there have been food safety concerns that have been linked in the past to glycoalkaloids in the raw potatoes that are used for processing. Potatoes are known to accumulate glycoalkaloids (GAs) during growth and postharvest storage. Some potato varieties have been shown to have high glycoalkaloids. These toxicants have been found to bioaccumulate in the body especially if daily consumption of foods containing the glycoalkaloids are consumed. Glycoalkaloids lead to intestinal discomfort, vomiting, fever, diarrhea and neurological problems and can lead to human or animal deaths in cases of acute toxicity. Transportation, handling, poor storage and exposure to sunlight during marketing of potatoes exposes consumers to potential risk of glycoalkaloids due to injury and greening which lead to increased levels of glycoalkaloids. Glycoalkaloids are quite stable and therefore, freeze-drying, boiling, dehydration or microwaving have got limited effect and thus persist through the processing conditions into the final products with the levels being proportional to the concentrations in the raw materials used. This current review focuses on the occurrence of glycoalkakloids in potato and potato products that are commonly consumed.

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 use in industrial food processing by the small and medium enterprises (SME's). The aim of this study was to establish suitability of these water sources for drinking and use in industrial food processing by the small and medium enterprises (SME's). A total of 60 surface and ground water sources samples were purposively collected aseptically from the four administrative units (Ngare Mara, LMD, Leparua, and Wabera) of Isiolo County. ISO 16649-3, 688-2, 7937, 9308-1, and 18744 were used for enumeration of E.coli, Staphylococcus aureus, Clostridium pafringens, Coliforms, and cysts. Highest mean Clostridium pafringens counts in ground and surface water were 1452 Cfu/ml and 3421 Cfu/ml, respectively. Mean Staphylococcus aureus counts were 740 Cfu/ml and 1333 Cfu/ml in surface water and ground water, respectively. Escherichia coli and Coliforms contamination accounted for 29.88 % and 88.2 %, respectively. Microbial counts in the water sources differed significantly (p≤0.05). Total coliforms had a significant negative relationship (r = -0.76) with residual chlorine. Ground and surface water sources were highly contaminated with microorganism to levels regarded as unsafe by the Kenyan and WHO standards for potable water. Point-of-use water disinfection is thus necessary.

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, concentrates, ready to serve beverages, wines, as well as jams and jellies. Although Kenya has a favorable climate for guava farming, the fruit’s nutritional and economic potential remain highly underutilized due to low adoption of processing and preservation techniques in addition to limited research. This review focuses on guava production utilization, processing and preservation with emphasis on Kenya There has been progressive increase in the total acreage under guava farming with various varieties of guavas being produced. The country produces as much as 11,327 tons of guava fruits worth 1.1 million US dollars although the fruit is mainly cultivated for local consumption with minimal processing. Naturalized guavas from sprouts of randomly dispersed seeds are common across all the agroecological zones both in the wild and on farms except in the arid areas. The fruit is however, climacteric and has a high rate of perishability resulting to high postharvest losses when in season. Processing of guavas into commercial products can increase the fruit’s value, improve farmers’ household incomes and enhance their utilization. The guava value chain also remains highly underexploited and since it is a neglected crop, there is need for a multisectoral approach in order to exploit the nutritional and economic potential of the fruit.

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 leaves of orange‐fleshed sweetpotato (OFSP) varieties called Kabode and SPK031. Yellosp and Whitesp, which are local sweetpotato varieties, were also included as check for roots and leaves, respectively. The sweetpotato products prepared for phytochemical analysis were boiling roots and leaves, frying chips and crisps, baking bread (for roots only), and fermenting and dehydrating leaves. Phytochemicals that were assessed included vitamin C, total phenolics and flavonoids, tannins, phytates, and soluble oxalates. Results indicated that retention of vitamin C was highest in boiled roots (85%–95%), followed by fries (71%–94%) and crisps (44%–76%), whereas the least retention was in bread (4%–11%) and leaves (0%–27%). Total phenolics, flavonoids, and antioxidant activity in leaves significantly (p < .05) varied with the type of processing. Higher retention of these phytochemicals was observed in processed roots but was lowest in bread. Boiling retained more than 100% of all carotenoids, while fermenting and drying the leaves retained 58–62 and 22%–48%, respectively. Frying retained more than 100% of the β‐carotene in the roots, while boiling retained 96%–100%. All processing methods significantly (p < .05) reduced antinutrients in leaves and roots. Fermentation of leaves had higher reduction of oxalates, tannins, and phytates, while boiling had the least effect. It is concluded that traditional boiling enhances phytochemical retention in roots but degrades most of them in leaves.