298 research outputs found

    Development of frozen-fried yam slices: Optimization of the processing conditions

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    The research performed on yam processing mainly concerns the production of crisps and flour. However, its transformation into deep-frozen French fries does not necessitate any other equipment than those used for potatoes. The industrial process of production of frozen French fries traditionally includes a pre-frying step. These steps contribute to the development of color and crispness, and the oil partially absorbed inhibits dehydration during the freezing step. The aim of this study was tooptimize frying conditions of deep-frozen fried yam (Dioscorea cayenensis var Kponan) slices. The effect of pre-frying time and temperature, final frying time and temperature on the oil uptake, texture, dry matter and colour of the fried yam slices has been studied. Frying conditions optimized with Box-Behnken experimental design were short pre-frying and frying conditions at high temperature characterized by prefryingtemperature at 157-170°C during 5-9s and frying temperature at 181-188°C for 2min 15s-2min 30s; or long pre-frying and frying conditions at low temperature characterized by pre-frying temperature at 150-158°C during 10-15s and frying temperature 170-177°C for 3-3min 15s. An adiabatic system was also developed by means of an insulator in which the core temperature of fried yam slices can be maintained constant at about 55°C after 15min of cooling, facilitating texture measurements at constant temperature. The present results may help in choosing the yam slices frying condition to be applied in order to achieve the desirable fried yamslices quality, required for protection against certain diseases like obesity. These models may also provide guidance as to how to control these quality parameters by altering four key environmental factors, pre-frying temperature and time and, final frying temperature and time. This process can also be commercialized and does not necessitate any other cost for equipment than those used for potatoes French fries and might be an interesting way of added value processing for this highly perishable yamtuber

    Influence de quelques facteurs environnementaux sur la germination d'Euphorbia heterophylla L. (Euphorbiaceae)

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    Influence of some Environmental Factors on Euphorbia heterophylla L. (Euphorbiaceae) Seeds Germination. In Ivory Coast, Euphorbia heterophylla appears as a weed in cotton fields. Effects of temperature, light and burying levels on its seed germination were tested. Temperature effects were monitored by means of 4 procedures, using a range of temperatures between 20 and 35 °C. The germination latency period can vary between 1 and 2 days, according to the temperature. After 4 days, germination rates were not longer related to temperature and were very similar. Germination can not happen without light. In order to measure the effect of burying levels, six series of 100 seeds were buried; the first at ground level, the others respectively 2, 4, 6, 8 and 9 cm deeper. Optimal germination rates were found for seeds that were buried between 0 and 6 cm

    Physicochemical and Nutritional Properties of Varieties of Carrot (Daucus carota) grown in Region of Korhogo, North of Côte d’Ivoire

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    Very popular for its therapeutic and nutritional virtues, culture of carrot (Daucus carota) has developed in temperate zones of Asia and Europe but also in some tropical regions of Africa including CĂ´te d'Ivoire. Agronomic factors, commercial and food requirements require selection of varieties with good nutritional values. In this study, physicochemical properties and nutritional values of four carrot varieties namely Amazonia, Bahia, Madona and Pamela+ were compared after cultivation and harvest in region of Korhogo. Results showed that, Amazonia, the control carrot variety stands out for its acidity and minerals levels. Bahia is the richest variety with high levels of carbohydrate and protein. Madona is the most basic, wettest and fatest carrot. For a long storage, Pamela is most interesting variety. To our knowledge, it is the first time that physicochemical and nutritional parameters of carrot varieties in region of Korhogo have been studied. Future research on these carrot varieties will be studied of their post-harvest conservation, their sensory analysis and their transformation

    Behavioural determinants of gene flow in malaria vector populations: Anopheles gambiae males select large females as mates

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    BACKGROUND: Plasmodium-refractory mosquitoes are being rapidly developed for malaria control but will only succeed if they can successfully compete for mates when released into the wild. Pre-copulatory behavioural traits maintain genetic population structure in wild mosquito populations and mating barriers have foiled previous attempts to control malaria vectors through sterile male release. METHODS: Varying numbers of virgin male and female Anopheles gambiae Giles, from two strains of different innate sizes, were allowed to mate under standardized conditions in laboratory cages, following which, the insemination status, oviposition success and egg batch size of each female was assessed. The influence of male and female numbers, strain combination and female size were determined using logistic regression, correlation analysis and a simple mechanistic model of male competition for females. RESULTS: Male An. gambiae select females on the basis of size because of much greater fecundity among large females. Even under conditions where large numbers of males must compete for a smaller number of females, the largest females are more likely to become inseminated, to successfully oviposit and to produce large egg batches. CONCLUSIONS: Sexual selection, on the basis of size, could either promote or limit the spread of malaria-refractory genes into wild populations and needs to be considered in the continued development and eventual release of transgenic vectors. Fundamental studies of behavioural ecology in malaria vectors such as An. gambiae can have important implications for malaria control and should be prioritised for more extensive investigation in the future

    Prévalence de la démence dans une population de personnes âgées sénégalaises

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    Description Avec le vieillissement de la population, survient la démence dans la population de personnes âgées. Objectif. L’objectif de cette étude était d’estimer la prévalence de cette affection dans une population de personnes âgées sénégalaises. Méthodes Par une étude transversale qui s’est déroulée du 01 mars 2004 au 31 décembre 2005, des personnes âgées de 55 ans et plus venant consulter pour un problème de santé au Centre Médico-Social et Universitaire de l’IPRES (Sénégal) ont été évaluées sur le plan clinique et neuropsychologique. Des données sur les caractéristiques sociodémographiques, les antécédents médico-chirurgicaux et familiaux, le mode de vie, le réseau social ont été collectées à l’aide d’un questionnaire structuré avec des réponses fermées. Résultat La population à l’étude était composée de 872 personnes. Elles avaient un âge moyen de 67,2 ans ± 7,5.Elles étaient de sexe masculin (62,6%), mariées (79%), non instruites (50,7%). Dans les antécédents, l’HTA, le diabète, les affections respiratoires, les affections rhumatismales, la cataracte et les troublesdigestifs étaient les plus fréquents. Le tabagisme et l’alcoolisme était faible alors que la marche constituait la principale activité physique. Les personnes âgées vivaient en famille avec un bon réseau social.Cinquante huit (58) personnes ont présenté une démence (6,6%). La prévalence de la maladie variait de manière significative avec l’âge et l’instruction. Conclusion Ce résultat confirme que la prévalence de la démence varie en fonction de l’âge et de l’instruction de la personne âgée

    Genetic Diversification and Selection Strategies for Improving Sorghum Grain Yield Under Phosphorous-Deficient Conditions in West Africa

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    Sorghum, a major crop for income generation and food security in West and Central Africa, is predominantly grown in low-input farming systems with serious soil phosphorus (P) deficiencies. This study (a) estimates genetic parameters needed to design selection protocols that optimize genetic gains for yield under low-phosphorus conditions and (b) examines the utility of introgressed backcross nested association mapping (BCNAM) populations for diversifying Malian breeding materials. A total of 1083 BC1F5 progenies derived from an elite hybrid restorer “Lata-3” and 13 diverse donor accessions were evaluated for yield and agronomic traits under contrasting soil P conditions in Mali in 2013. A subset of 298 progenies were further tested under low-P (LP) and high-P (HP) conditions in 2014 and 2015. Significant genetic variation for grain yield was observed under LP and HP conditions. Selection for grain yield under LP conditions was feasible and more efficient than the indirect selection under HP in all three years of testing. Several of the BCNAM populations exhibited yields under LP conditions that were superior to the elite restorer line used as a recurrent parent. The BCNAM approach appears promising for diversifying the male parent pool with introgression of diverse materials using both adapted Malian breed and unadapted landrace material from distant geographic origins as donors
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