Quality characterization of bread retailed in Nairobi County, Kenya: Physico-chemical and microbial profiles

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 processing that is evidenced in product quality. The current study employed a cross-sectional survey of bread retailed in the fourteen supermarkets located in Nairobi County, Kenya to determine their physico-chemical and microbiological characteristics. The study showed that brown bread had significantly (p<0.001) higher moisture and water activity, although the fibre and total solids in the brown bread were significantly (p<0.01) lower than the white bread. The greatest variability in the physicochemical attributes was found in the acid insoluble ash, with a coefficient of variation of 82.04%. The highest proportion of the bread, 58.9%, fell short of meeting the regulatory stipulations of the acid insoluble ash.  Significantly (p<0.05) higher proportion of the brown bread (60.7%) than the white bread (4.4%) had crude fibre contents less optimalthan the regulatory stipulations. The greatest adherence to product quality stipulations was found in yeast and mould counts (100%), moisture content (99.1%) and pH aqueous extract (95.5%). Both the brands of bread and retail outlets had quarter of them recording higher moisture, water activity and total acid insoluble ash than the averages of breads  traded in supermarkets; whereas the pH, fibre and total solids were lower (kmean clusters=2). Eight principal components maximally explained product variability in the breads, with similar trends of composition between moisture and protein, and fibre and total solids, whereby the latter pair had a negative  correlation with the former. In conclusion, the study found that the formal sector still falls short of product quality regulatory stipulations, pointing to greater need to strengthen surveillance component of food control for this sector. Key words: White, Brown, Bread, Food control, Cluster Analysis, Proximate, Supermarket, Standard

Physico-chemical Characteristics of Refined Lake Victoria Nile Perch (Lates niloticus) Viscera Oil

Nile perch viscera oil was characterized in terms of its physico-chemical properties. The crude oil was refined by neutralization, deodorization and winterization to obtain low melting point (LMP) and the high melting point (HMP) fractions. The oil fractions were analyzed for omega – 3 fatty acids (eicosapentaenoic acid – EPA and docosahexaenoic – DHA), vitamin A, vitamin E, iodine value (IV), saponification value (SV), density, melting point (MP), and smoke point (SP). Crude was used as control. Data were analysed (p £ 0.05) using GenStat software. The yield of winterized oil (LMP) was 39.8 ± 0.5% of crude and 19.6 ± 0.5% of raw material weight. There were no significant differences in density and vitamin E (tocopherol) content of the three fractions, while there were significant differences in the slip MP, SP, SV, IV and vitamin A (retinol) content. There were also significant differences in EPA and DHA contents. EPA and DHA for the LMP were highest, followed by crude and HMP having lowest. High vitamins A and E as well as omega – 3 polyunsaturated fatty acids (ω – 3 PUFA) contents and high SP make the crude and HMP fractions suitable for use in cooking. The high amount of LMP fraction has high content of ω – 3 PUFA, making it suitable for use in food, feed and nutraceutics. Keywords: Nile perch; viscera; wet rendering; refining; physico-chemical characteristic

Evaluation of nutrient content in red kidney beans, amaranth leaves, sweet potato roots and carrots cultivated in Rwanda

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 subjected to quantitative analysis for proximate content, energy, calcium (Ca), iron (Fe), zinc (Zn), vitamin A and vitamin C. Proximate composition determination was done using Near Infrared Spectroscopy (NIRS), carbohydrates were determined by difference, energy was calculated, mineral analysis was done by Atomic Absorption Spectroscopy (AAS) and vitamin analysis was performed by High Performance Liquid Chromatography (HPLC) methods. The results showed that red kidney beans, sweet potato roots, amaranth leaves and carrots contain 21.48, 6.66, 29.46 and 13.8% of protein; 2.58, 1.68, 7.89 and 2.08% of fat; 60.86, 79.13, 19.29 and 57.38% of carbohydrate; 2.33, 2.68, 8.98 and 9.63% of fiber; 8.82, 8.74, 10.08 and 8.88% of moisture content; 3.94, 1.11, 24.30 and 5.16% of ash; 357.2, 363.7, 284.0, 322.9 kcal/100 g of energy; and 146.4, 182.7, 26,290 and 1,247 mg/kg of calcium, respectively. Red kidney beans, amaranth leaves and carrots contained 8.54, 30.48, and 15.55 mg/kg of zinc; and 21.36, 219.1 and 8.81 mg/kg of iron, respectively. Zinc and iron were, however, not detected in sweet potato samples analysed. Red kidney beans, sweet potato roots, amaranth leaves and carrot contained 768.0, 10,880, 399.4, and 6,413 IU/100 g of vitamin A; and 2.67, 30.99, 330.3 and 6.76 mg/100g of vitamin C, respectively. In conclusion, the staples analysed contained appreciable amounts of nutrients and could be used to overcome malnutrition and allow dietary diversity. It could be recommended to prepare a Rwandan food composition database in order to improve awareness on local grown crops’ quality

PHYSICO-CHEMICAL PROPERTIES AND SENSORY QUALITY OF CASSAVA-COWPEA-MILLET COMPOSITE FLOURS

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 flour products, namely 20:50:30, 10:50:40 and 15:60:25 of cassava roots, cowpea leaves, and millet, respectively to achieve more than 40% daily requirement of protein, iron and zinc for the expectant woman. The products were subjected to a sensory panel and evaluated against a standard commercial flour (Famila) sold in the Kenyan market. The flours were also subjected to accelerated shelf-life study based on physico-chemical properties and growth of yeast and molds. Results indicated that 20:50:30 and 10:50:40 had the highest colour scores on a 7-point hedonic scale, 5.2\ub11.35 and 5.2\ub11.48 (P<0.05). The score indicates a near equal acceptability of the flour based on colour for both the standard. The green porridge (15:60:25) was the least accepted flour and had the highest total aerobic count of 3.7 log cfu g-1 after four months of storage. The acid value of the flours ranged from as low as 1.84\ub10.01mg KOH g-1 for the 20:50:30 at day zero and as high as 12.9\ub11.73 mg KOH g-1 after six months of storage. The formulated 20:50:30 flours had protein (8.0%), fat (3.5%) carbohydrates (70%), zinc (0.6 mg100 g-1), iron (0.6 mg100g-1) and vitamin C (0.3 mg100 g-1).Il y a une augmentation mondiale de la demande d\u2019une bonne sant\ue9 et d\u2019une bonne nutrition. L\u2019objectif de cette \ue9tude \ue9tait de formuler des farines composites nutritives \ue0 partir de racines de manioc ( Manihot esculenta L.), de feuilles de ni\ue9b\ue9 ( Vigna unguiculata ) et de mil ( Pennisetum glaucum ), en particulier pour les enfants et les femmes enceintes. Un logiciel Nutrisurvey a \ue9t\ue9 utilis\ue9 pour formuler trois produits \ue0 base de farine, \ue0 savoir 20:50:30, 10:50:40 et 15:60:25 de racines de manioc, de feuilles de ni\ue9b\ue9 et de millet, respectivement, pour atteindre plus de 40% des besoins quotidiens en prot\ue9ines , fer et zinc pour la femme enceinte. Les produits ont \ue9t\ue9 soumis \ue0 un panel sensoriel et \ue9valu\ue9s par rapport \ue0 une farine commerciale standard (Famila) vendue sur le march\ue9 au Kenya. Les farines ont \ue9galement \ue9t\ue9 soumises \ue0 une \ue9tude de dur\ue9e de conservation acc\ue9l\ue9r\ue9e bas\ue9e sur les propri\ue9t\ue9s physicochimiques et la croissance des levures et des moisissures. Les r\ue9sultats ont indiqu\ue9 que 20:50:30 et 10:50:40 avaient le couleur les plus \ue9lev\ue9s sur une \ue9chelle h\ue9donique \ue0 7 points, 5,2 \ub1 1,35 et 5,2 \ub1 1,48 (P <0,05). L\u2018 \ue9chelle h\ue9donique indique une acceptabilit\ue9 presque \ue9gale de la farine sur la base de la couleur pour le standard. La bouillie verte (15:60:25) \ue9tait la farine la moins accept\ue9e et avait le compte a\ue9robie total le plus \ue9lev\ue9 de 3,7 log ufc g-1 apr\ue8s quatre mois de stockage. L\u2019indice d\u2019acide des farines variait entre 1,84 \ub1 0,01 mg KOH g-1 pour le 20:50:30 au jour z\ue9ro et jusqu\u2019\ue0 12,9 \ub1 1,73 mg KOH g-1 apr\ue8s six mois de stockage. Les farines formul\ue9es \ue0 20:50:30 contiennent des prot\ue9ines (8,0%), des lipides (3,5%), des glucides (70%), du zinc (0,6 mg100 g- 1), du fer (0,6 mg100g- 1) et de la vitamine C (0,3 mg100 g- 1)

MICROBIOLOGICAL SAFETY AND QUALITY OF DRIED CASSAVA CHIPS AND FLOUR SOLD IN THE NAIROBI AND COASTAL REGIONS OF KENYA

Cassava ( Manihot esculenta Crantz) is rich in carbohydrates and is the third most important source of calories, in the tropics. The handling and processing practices of cassava roots expose them to microbial contamination. The objective of this study was to assess the level of contamination of cassava products that are in markets so as to establish the safety for human consumption. Samples from Nairobi and Coastal region of Kenya were evaluated for: total count, Staphylococcus aureus , total coliforms, yeast and mould and E. coli to establish their safety and quality for human consumption. Results for dried cassava chips showed; TVC 5.16-8.04 log cfu g-1; 4.81-7.21 log cfu g-1, mould 1.00-3.86 log cfu g-1; 1.00-3.28 log cfu g-1 and Staphylococcus aureus 2.69-4.36 log cfu -1; 2.90-4.71 log cfu -1 for Nairobi and Coastal region respectively. Cassava flour was; TVC 5.66-7.67 log cfu g-1; 5.92-8.12 log cfu g-1, mould 1.00-6.73 log cfu g-1; 2.65-5.08 log cfu g-1, Staphylococcus aureus 3.77-5.79 log cfu g-1; 1.00-5.73 log cfu g-1, and coliforms 0-6.34; 2.00-6.27 log cfu g-1 for Nairobi and Coastal regions respectively. One sample tested positive for presence of E. coli. Eighty seven percent of cassava flour and 77% of dried cassava chips samples were confirmed for presence of Staphylococcus aureus. There was a significant (P<0.05) difference in the microbial counts among the dried cassava chips samples and the cassava flour samples from markets in Nairobi and Mombasa. Results indicate excessive manual and poor post-harvest handling practices of the products hence, their poor quality and non-safety for consumption.Manioc ( Manihot esculenta Crantz) est riche en hydrates de carbone et est la troisi\ue8me plus importante source de calories, sous les tropiques. Les pratiques de manipulation et de traitement des racines de manioc les exposent \ue0 la contamination microbienne. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer le niveau de contamination des produits de manioc qui sont sur les march\ue9s afin d\u2019\ue9tablir la s\ue9curit\ue9 pour la consommation humaine. Les \ue9chantillons provenant de Nairobi et de la r\ue9gion c\uf4ti\ue8re du Kenya ont \ue9t\ue9 \ue9valu\ue9s pour: nombre total, Staphylococcus aureus , coliformes totaux, levures et moisissures et E. coli pour \ue9tablir leur s\ue9curit\ue9 et de qualit\ue9 pour la consommation humaine. R\ue9sultats pour les cossettes de manioc s\ue9ch\ue9es ont montr\ue9; TVC de 5,16 \ue0 8,04 log ufc g-1; 4,81 \ue0 7,21 log ufc g-1, moule de 1,00 \ue0 3,86 log ufc g-1; 1,00 \ue0 3,28 log ufc g-1 et Staphylococcus aureus 2,69 \ue0 4,36 log ufc-1; 2,90 \ue0 4,71 log ufc-1 pour Nairobi et de la r\ue9gion c\uf4ti\ue8re, respectivement. La farine de manioc \ue9tait; TVC 5,66 \ue0 7,67 log ufc g-1; 5,92 \ue0 8,12 log ufc g-1, moule de 1,00 \ue0 6,73 log ufc g-1; 2,65 \ue0 5,08 log ufc g-1, Staphylococcus aureus 3,77 \ue0 5,79 log ufc g-1; 1,00 \ue0 5,73 log ufc g-1, et les coliformes 0 \ue0 6,34; 2.00-6.27 log ufc g-1 pour Nairobi et c\uf4ti\ue8res des r\ue9gions respectivement. Un \ue9chantillon a \ue9t\ue9 test\ue9 positif pour la pr\ue9sence de E. coli. Quatre-vingt-sept pour cent de farine de manioc et 77% des \ue9chantillons s\ue9ch\ue9s chips de manioc ont \ue9t\ue9 confirm\ue9es pour la pr\ue9sence de Staphylococcus aureus. Il y avait une diff\ue9rence significative (P <0,05) dans les comptes microbiens parmi les cossettes de manioc \ue9chantillons s\ue9ch\ue9s et les \ue9chantillons de farine de manioc en provenance des march\ue9s \ue0 Nairobi et Mombasa. Les r\ue9sultats indiquent manuelles et mauvaises pratiques excessives de manutention post-r\ue9colte des produits donc, leur mauvaise qualit\ue9 et non-s\ue9curit\ue9 pour la consommation

QUALITY AND SAFETY CHARACTERISTICS OF CASSAVA CRISPS SOLD IN URBAN KENYA

Cassava ( Manihot esculenta Crantz) crisps are increasingly popular in Kenya\u2019s urban areas. Crisps are popularly consumed as snacks outside homes and in-between meals. However, limited information on the quality and safety of the crisps is available in the country. This study sought to characterise the quality and safety in terms of cyanide levels of cassava crisps commercially traded in Mombasa and Nairobi areas in Kenya. Samples of six commercially traded crisp brands were collected in duplicates, from venders and supermarkets; and evaluated for moisture, oil, cyanide and sodium chloride contents. Product colour and texture were also evaluated. There were significant differences among brand contents of moisture (P=0.0001), oil (P<0.0001) and cyanide content (P=0.026). Levels of sodium chloride were, however, insignificant (P>0.07). Moisture content ranged from 4.3 to 6.77%, oil content 19.17 to 30.68%; and cyanide and salt contents ranged 13.5 to 32.24 ppb and 2.3 to 2.7%, respectively. There were no significant differences (P>0.57) in the texture, as well as in the yellowness (b*) parameter (P>0.137). On the other hand, significant differences were observed on colour. Moisture and cyanide levels exceeded the statutory limits.Le chips de manioc ( Manihot esculenta Crantz) deviant de plus en plus populaire dans les zones urbaines du Kenya. Les chips son generalemant consommes sous forme de gouter en dehors de la maison et au mileu de deux repas. Neanmoins, tres peu d\u2019informations sont disponibles sur la qualite et l\u2019hygienne des chips vendus au Kenya. Cette etude visait a faire le point de la qualite et de l\u2019hygienne en terme de quantite de cyanure du manioc dans les chips commercializes dans les villes de Mombasa et Nairobi au Kenya. Des echantillons de six marques de chips commercializes ont ete collectes chez des vendeurs et supermarches, et ont ete evalues pour leur taux d\u2019humidite, d\u2019huile, de cyanure et de chlorure de sodium. La couleur et la texture ont ete aussi evaluee. Des differences significatives ont ete observes dans les taux d\u2019humidite (P=0,0001), d\u2019huile (P<0,0001) et de cyanure (P=0,026) d\u2019une marque a une autre. Les taux de chlorure de sodium n\u2019etait pas significativement differents (P>0,07). les taux d\u2019humidite varient de 4,3 a 6,77%, ceux d\u2019huile de 19,17 a 30,68%; tandis que ceux de cyanure et de sel varient respectivement de 13,5 a 32,24 ppb et 2,3 a 2,7%. Aucune difference significative n\u2019etait observee dans la texture (P>0.57), ni dans l\u2019inde de teinte jaune (b*) (P>0.137). D\u2019autre part, des differences significatives ont ete observes au niveau des couleurs. Les taux d\u2019humidite et de cyanure depassaient les limites statutaires; d\u2019ou de potentiel dangers pour la sante des populations

Seasonal fluctuations and damage of lepidopteran stemborers of maize in a major agroecozone of Uganda

The distribution and damage of stemborers of maize, Chilo partellus (Swinhoe), Busseola fusca (Fuller), Eldana saccharina Walker, and Sesamia calamistis Hampson, were studied in two locations in Uganda. The species composition of the stemborers was influenced by crop phenology. Distribution of stem borer larvae in the plant was similar at both locations. At 2-3 weeks after plant emergence (WAE), 100% of larvae recovered was from the funnel of the plant with the proportion decreasing as the stem elongated. Busseola fusca and Chilo partellus were more injurious as indicated by the extent of leaf and stem injury. Sesamia calamistis predominantly attacked the maize ears. This phenological relationship of variation in stemborer incidence and damage to crop phenology is crucial in devising management strategies of the pests.La distribution et les degets causes par les insectes terebrants (stemborers) des tiges du mais, Chillo partellus (Swinhoe), Busseola fusca (Fuller), Eldama Saccharina Walker, et Sesamia calamistis Hampson, ont ete etudies dans deux endroits en Ouganda. La composition specifique des insectes terebrants a ete influencee par la phenologie de la culture. La distribution des larves des insectes terebrants dans la plantes s'est revelee semblable dans les deux sites. Deux a trois semaines apres l'emergence de la plante (WAE), 100% des larves retrouvees provenaient de la cheminee de la plante avec une proportion decroissant avec l'elongation de la tige. Busseola fusca et Chilo partellus etaient plus agressives comme l'indiquaient l'etendue de la feuille et la blessure de la tige. Sesamia calamistis attaquait surtout les epis du mais. Cette relation phenologique de la variation dans l'incidence des insectes terebrants sur les tiges et les degets causee a la phenologie de la culture est cruciale dans les strategies combinees du controle des pestes

Efficacy of different insecticides for the management of stemborers of maize in Uganda

Evaluation was made of the efficacy of commonly available insecticides for control of stemborers on maize. Insecticide application influenced the occurrence and extent of stemborer damage on maize. In the early stages of crop development, the lowest stemborer incidence was recorded on Furadan treated plots, although its efficacy decreased with time. Overall, Sevin treatments effected better control compared to other treatments. A well timed granular application of Sevin could fit well in the integrated stemborer management system and reduce maize yield losses caused by these pests.L'efficacite des insecticides communement disponibles dans la lutte contre les insectes terebrants des tiges du mais a ete evaluee dans la presente etude. L'application de l'insecticide a influence l'existence et l'importance des degets causes par les insectes terebrants sur le mais. Au cours des premiers stades de developpment de la culture, la plus faible incidence de l'insecte terebrant a ete enregistree sur les parcelles traitees avec du furadan, bien que son efficacite ait diminue avec le temps. Dans l'ensemble, les traitements avec du sevin ont produit un meilleur control par rapport a d'autres traitements. Une application granulaire du sevin mieux chronometree conviendrait mieux dans le systeme integre de la gestion de l'insecte terebrant et reduisait les pertes de la productivite du mais causees par ces pestes

Phytochemicals in leaves and roots of selected Kenyan orange fleshed sweet potato (OFSP) varieties.

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 () among the sweet potato varieties regardless of the plant part, leaves having significantly () higher levels than in the roots. Total flavonoids and phenolic compounds differed significantly () among varieties, higher values were found in leaves than in roots. Flavonoid contents in roots ranged from below detectable limits (Whitesp) to 25.8 mg CE/100 g (SPK031), while in leaves it ranged from 4097 to 7316 mg CE/100 g in SPK4 and Kenspot 5, respectively. Phenolic content was below detectable limits in the roots of whitesp but it was in substantial amounts in orange fleshed varieties. The β-carotene content was significantly () higher in leaves (16.43–34.47 mg/100 g dry weight) than in roots (not detected—11.1 mg/100 g dry weight). Total and phytic phosphorus were directly correlated with phytate contents in leaves and the roots. Tannins and soluble oxalates varied significantly () with variety and plant part being higher in leaves. The current information is important for ration formulations and dietary recommendations utilizing sweet potato leaves and roots. Future studies on effects of processing methods on these phytochemicals are recommended

Processing methods affect phytochemical contents in products prepared from orange‐fleshed sweetpotato leaves and roots

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 beta-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