Robert NDJOUENKEU | The University of Ngaoundéré (original) (raw)
Papers by Robert NDJOUENKEU
![Research paper thumbnail of Biochemical functional and physical characterization of Bambara groundnut [Vigna subterranea (L.) Verdc. Fabaceae] seeds grown in septentrional area of Cameroon](https://attachments.academia-assets.com/118128698/thumbnails/1.jpg)
](Journal of agricultural, food science & biotechnology, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License (CC BY-NC 4.0).
Journal of experimental agriculture international, Aug 11, 2022
Research Problem: Cassava leaves play an important role in the diet of the Central African popula... more Research Problem: Cassava leaves play an important role in the diet of the Central African population. Several studies have investigate the composition in nutrients of cassava leaves but only few study focused on the impact of the cassava mosaic virus disease, the main threat of the cassava production in sub-Saharan Africa, on the nutritional value of infected cassava leaves. The objective of this work is to determine the content of nutritional and anti-nutritional compounds in cassava leaves infected by the mosaic virus and healthy leaves. Material and Methods: The study was performed on two cassava varieties that are M66033 (susceptible to be infected by the mosaic virus) and Togo or TMS66 (resistant to the virus) planted Original Research Article
Journal of enzyme research, 2014
Leaves of Abrus precatorius, tubers of Burnatia enneandra and stems of Cadaba farinosa are used i... more Leaves of Abrus precatorius, tubers of Burnatia enneandra and stems of Cadaba farinosa are used in savannah regions of Cameroon in traditional food processing, particularly in sweetening and liquefaction of gruels. α-amylase was extracted and partially purified from these plants using conventional methods of protein purification including ammonium sulfate fractionation and two steps of gel filtration. Purification achieved 58, 61 and 46 fold respectively for A. precatorius, B. enneandra and C. farinosa. The purified enzymes were then characterized in terms of molecular weight, optimum pH and stability, optimum temperature and stability, Km, Vmax and metals ions effects. The optimum pH of enzymes varied from 6.0 for amylases from B. enneandra and C. farinosa, to 7.0 for amylase from A. precatorius; while the optimum temperature was 60°C for amylases from A. precatorius and B. enneandra, and 65°c for amylase from C. farinosa. The three enzymes displayed, respectively for A. precatorius, B enneandra and C farinosa, a molecular weight of 60, 65 and 48.5 kDa, Km for hydrolyzing soluble starch of 3.25, 1.81 and 3.18 mg/ml, and strong individual activation by Ca 2+ , Co 2+ and Fe 3+. Li 2+ appeared as a common activator for all the amylases, while Ag + , Hg 2 + , Zn 2+ and Cu 2+ act as common inhibitors.
Oilseeds and fats, crops and lipids, Jul 1, 2006
The effect of some processing parameters (thickness of kernels, kernels to butter mass ratio, tem... more The effect of some processing parameters (thickness of kernels, kernels to butter mass ratio, temperature and duration of frying) on the acid and peroxide values and the melting properties of shea butter was studied during deep fat frying of shea kernels (Butyrospermum parkii). The results showed that the frying of kernels results in low acidic butters fulfilling commercial criteria of acidity. The increase of the frying temperature increased the peroxide value. The thermograms of butters from fried kernels dispayed a peak intermediate to both typical peaks of shea butter. The melting enthalpy of this peak increased with increasing the temperature and the duration of frying. The best frying conditions to preserve the quality of shea butter are: kernel thickness 2-6 mm; frying temperature 140-150°C, kernel to butter mass ratio 0,04-0,06 and duration of frying less than 10 minutes.
HAL (Le Centre pour la Communication Scientifique Directe), 2003
-Les cultures de tomate sont importantes dans l'Extrême-Nord du Cameroun et dans le Ouadaï au Tch... more -Les cultures de tomate sont importantes dans l'Extrême-Nord du Cameroun et dans le Ouadaï au Tchad. Les contraintes liées aux conditions de traitement et de conservation des cultures ont conduit les paysans, notamment ceux du nord-est du Tchad, à valoriser leurs productions sous forme de poudre séchée au soleil. Le produit obtenu trouve un circuit de distribution sur les marchés de N'Djamena, Maroua et Garoua. Toutefois, la qualité marchande de cette poudre de tomate reste limitée par une couleur terne et une charge élevée en impuretés. Des essais de laboratoire, menés à l'ENSAI de Ngaoundéré, montrent qu'un prétraitement des fruits, avant séchage, à 60°C pendant 12 heures dans une solution saturée de sel, ou bien pendant 20 heures dans une solution sucrée à 600 g/l, améliorent la couleur de la poudre. Ces conditions technologiques sont transférables en milieu paysan, en raison de la simplicité de leur mise en oeuvre. Les résultats obtenus offrent ainsi une opportunité de recherche appliquée pour améliorer la qualité de la poudre de tomate.
Journal of entomology and zoology studies, Mar 1, 2016
In Sub Saharan Africa, one of high potential nutritional crop is the Bambara groundnut. Popular a... more In Sub Saharan Africa, one of high potential nutritional crop is the Bambara groundnut. Popular and neglected legume, it is available in very low amount despite of being the richest seeds in lysine and methionine. To enhance the production of this crop and raise it as a strategic crop to fight hunger, the present work investigate in smallholders farms, the typology of systems of production of Bambara groundnuts in Adamawa Region of Cameroon. After 2 agricultural campaigns, storage facilities, morphotypes cultivated, storing method and protective tools to secure stored seeds were censed. Two bruchids (Coleoptera: Chrysomelidae): Callosobruchus subinnotatus (Bridwell) and Callobruchus maculatus (Fabricius), are major pests present on 10 of the 14 morphotypes of Bambara groundnuts sampled. To alleviate their damages, hazardous pesticides are currently used by producers, the possibility for developing some alternatives from local tools is discussed.
Des tranches de patate douce de 0,5 mm, 1 mm et 2 mm d'epaisseur, ont ete blanchies et/ou pre... more Des tranches de patate douce de 0,5 mm, 1 mm et 2 mm d'epaisseur, ont ete blanchies et/ou presechees, puis frites a 150 + 5 C. L'etude du comportement des tranches aux pretraitements a montre que le blanchiment a 65 C ou a 75 C est plus efficace pour l'elimination des sucres reducteurs et l'inactivation des polyphenols oxydases. Au cours de la friture, l'essentiel des echanges huile-eau s'effectue pendant les 10 ou 20 premieres secondes de friture, leur cinetique etant influencee a la fois par l'epaisseur des tranches, les pretraitements et le temps de friture. L'absorption d'huile semble cependant plus tributaire de l'epaisseur des tranches que des pretraitements. Les valeurs minimales d'huile absorbees par les tranches de 2 mm d'epaisseur laissent supposer que ces dernieres seraient plus convenables pour la production de chips de qualite. (Resume d'auteur)
Journal of applied biotechnology & bioengineering, Jan 17, 2017
TSM, Jul 1, 2019
L’eau du bassin versant de la Menoua subit de plein fouet le phénomène de pollution induite par l... more L’eau du bassin versant de la Menoua subit de plein fouet le phénomène de pollution induite par les activités anthropiques très nombreuses dans la région. L’objectif de ce travail est d’étudier l’évolution spatio-temporelle de la qualité métallique de l’eau de consommation humaine du bassin versant de la Menoua, dans le but d’évaluer son degré de pollution due aux activités anthropiques. Cela afin d’estimer le niveau de risque sanitaire que court la population exposée à sa consommation. L’analyse physico-chimique (pH, température, conductivité électrique, turbidité et oxygène dissous) et métallique (Pb, Ni, Fe, Zn et Cu) a été faite sur 132 échantillons prélevés dans 33 sites répartis durant deux saisons, dont deux campagnes en saison sèche et deux autres en saison pluvieuse. Il en ressort que les eaux ont un pH acide compris entre 5,70 et 6,02, une faible minéralisation, une conductivité comprise entre 107,85 et 146,74 μS/cm et une forte turbidité comprise entre 0,58 et 0,68 NFU. Les résultats d’analyse en métaux mettent en évidence une forte contamination en fer, compris entre 0,79 et 0,89 mg/L, avec une toxicité forte, le quotient de danger étant supérieur à 1. Les autres métaux, Pb, Zn, Cu, Ni présents dans les ressources sont révélateurs d’une pollution anthropique, mais ne constituent pas un risque pour la boisson.
Journal of experimental agriculture international, Jan 10, 2017
Journal of the Science of Food and Agriculture
BackgroundCassava processing is a crucial source of livelihood for rural farmers and processors i... more BackgroundCassava processing is a crucial source of livelihood for rural farmers and processors in Nigeria and Cameroon. This study investigated the varietal effect on the processing productivity of women farmer processors within their working environment and compared this to the field yield and the food product quality as evaluated by the processors. Field trials were established in Nigeria (Benue and Osun state) and Cameroon (Littoral zone). Eight cassava genotypes, including improved, regional, and processors' preferred checks were evaluated. Roots of these genotypes were harvested, and processed into gari and eba by processors with the time of each processing step recorded. Through pairwise ranking processors assessed the quality of the roots and food products.ResultsSuperior field performance of improved genotypes was observed over checks in Cameroon and Nigeria (Benue state) for dry matter content and fresh and dry yield. During processing, genotypes showed significant var...
Food bioscience, Apr 1, 2022
Zenodo (CERN European Organization for Nuclear Research), Sep 7, 2022
Bonagoum Men Agriculture (all), trade, transport (men) Women Agriculture (all), fishing (men), tr... more Bonagoum Men Agriculture (all), trade, transport (men) Women Agriculture (all), fishing (men), trade, hunting, breeding Bonamukandjo I Men Agriculture (all), trade, task work (mainly men from NorthWest) Women Agriculture (all), trade Passim Men Agriculture (all), breeding, task work Women Agriculture (all) Nkongsoung Long Trait Women Agriculture (all), breeding, trade Quartier 5 Men Agriculture (all), trade, breeding Women Agriculture (all), trade, breeding Distinction between farmers is generally done in two classes: wealthy and poor. Although data clearly show that there are middle farmers, it is difficult for interviewee to characterize these ones. Differences between wealth categories are in terms of land ownership, type of culture, farmed surface, and harvested quantities (table 3). In this respect Wealthy have land ownership, invest * I: Improved Variety, old released; L: Local variety; For each variety, the number of each gender in the brackets is the number of persons which have selected this variety
Bioresources and Bioprocessing, Dec 1, 2018
Background: Biosurfactants are natural surface-active compounds produced by a variety of microorg... more Background: Biosurfactants are natural surface-active compounds produced by a variety of microorganisms. The high cost of culture media limits the large-scale production and use of biosurfactants. It is therefore necessary to develop an efficient and cost-effective bioprocess to improve the yield of biosurfactants from microorganisms. In this study, the response surface method was used to optimize the production of biosurfactants by a Lactobacillus strain and the antimicrobial activity of the biosurfactants was assessed. Results: The biosurfactant-producing strain was identified as Lactobacillus paracasei subsp. tolerans N2 after 16S rRNA gene analysis. Among the different variables studied using a Plackett-Burman statistical design, temperature and peptone and sugar cane molasses concentrations were found to be the main factors that had significant (p < 0.05) influence on biosurfactant production. The results of this study showed that molasses concentration at 59.5 g/L, peptone at 6.20 g/L and temperature of 33 °C were optimal conditions for biosurfactant production, with a maximum yield of 2.70 g/L. The biosurfactant exhibited surface tension reduction of 37.85 mN/m and antimicrobial activity expressed as inhibition diameter of 63 mm. Partial characterizations by elemental, biochemical and Fourier transmission infrared spectroscopy analysis of the biosurfactant produced revealed that it was glycolipoprotein in nature. The biosurfactant exhibited bactericidal activity against Pseudomonas aeruginosa PSB2, Pseudomonas putida PSJ1, Salmonella sp. SL2, Escherichia coli MTCC 118, Bacillus sp. BC1 and Staphylococcus aureus STP1 at concentrations ranging from 6.4 to 50 mg/mL. Conclusion: The yield of biosurfactant was four-fold higher after optimization of media components and culture conditions using response surface methodology. The results of this study suggested that sugar cane molasses can be used as a low-cost substrate to enhance the yield of biosurfactants with antimicrobial activity.
Journal of the Science of Food and Agriculture
BACKGROUNDNigeria and Cameroon are multi‐ethnic countries with diverse preferences for food chara... more BACKGROUNDNigeria and Cameroon are multi‐ethnic countries with diverse preferences for food characteristics. The present study aimed to inform cassava breeders on consumer‐prioritized eba quality traits. Consumer testing was carried out using the triadic comparison of technologies (tricot). Diverse consumers in villages, towns and cities evaluated the overall acceptability of eba made from different cassava genotypes. Data from both countries were combined and linked to laboratory analyses of eba and the gari used to make it.RESULTSThere is a strong preference for eba with higher cohesiveness and eba from gari with higher brightness and especially in Cameroon, with lower redness and yellowness. Relatively higher eba hardness and springiness values are preferred in the Nigerian locations, whereas lower values are preferred in Cameroon. Trends for solubility and swelling power of the gari differ between the two countries. The study also reveals that the older improved cassava genotype...
Springer eBooks, 2022
The development and scaling out of flash-dryer innovations for more efficient, small-scale produc... more The development and scaling out of flash-dryer innovations for more efficient, small-scale production of high-quality cassava flour (HQCF) and starch is described. The diagnoses of cassava-processing SMEs (small and medium enterprises) revealed their energy expenditures for drying were considerably higher than those of large-scale industrial companies, which was mostly due to suboptimal design of flash-drying systems. As a result, small-scale production of cassava starch and HQCF often incurs high production costs, incompatible with market prices of final products. Taking stock of this situation, RTB scientists have developed several innovations to optimize energy efficiency and costs, including a longer drying pipe, reengineered heat exchanger, larger blower for higher air velocity, and a higher product/air ratio. This was based on numerical modelling to determine the key design features of energy-efficient flash dryers, followed by construction and demonstration of a pilot-scale prototype. As a result, improved small-scale flash dryers are now being scaled out to the private sector in various countries, using the Scaling Readiness framework and achieving 10-15% gains in productivity and incomes. A method for diagnosis of process efficiency is also described, to identify technical bottlenecks and to document and measure the outcomes and impacts during the implementation of scaling-out projects.
European Scientific Journal, ESJ, 2018
The health risk associated with the consumption of water polluted by humans in the World, particu... more The health risk associated with the consumption of water polluted by humans in the World, particularly in Africa, is a real public health problem. This is why WHO, from its inception in 1948, has always been concerned with defining limit values. The aim of this work was to study the physicochemical and microbiological quality of water in the Menoua watershed through a spatiotemporal dynamics to assess its degree of anthropogenic pollution and to estimate the level of risk of infection and diseases inherent in its consumption. Physicochemical analysis (pH, temperature, turbidity and dissolved oxygen) and microbiological (E-coli, salmonella and shigellas) was carried out on 132 samples taken from 33 sites distributed in two seasons, two in dry seasons and two in rainy season. The results show that these waters have an acidic pH, a low dissolved oxygen content, strong microorganism levels all correlated with high turbidity. These very high levels of microorganism, illustrate well the e...
Journal of agricultural, food science & biotechnology, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License (CC BY-NC 4.0).
Journal of experimental agriculture international, Aug 11, 2022
Research Problem: Cassava leaves play an important role in the diet of the Central African popula... more Research Problem: Cassava leaves play an important role in the diet of the Central African population. Several studies have investigate the composition in nutrients of cassava leaves but only few study focused on the impact of the cassava mosaic virus disease, the main threat of the cassava production in sub-Saharan Africa, on the nutritional value of infected cassava leaves. The objective of this work is to determine the content of nutritional and anti-nutritional compounds in cassava leaves infected by the mosaic virus and healthy leaves. Material and Methods: The study was performed on two cassava varieties that are M66033 (susceptible to be infected by the mosaic virus) and Togo or TMS66 (resistant to the virus) planted Original Research Article
Journal of enzyme research, 2014
Leaves of Abrus precatorius, tubers of Burnatia enneandra and stems of Cadaba farinosa are used i... more Leaves of Abrus precatorius, tubers of Burnatia enneandra and stems of Cadaba farinosa are used in savannah regions of Cameroon in traditional food processing, particularly in sweetening and liquefaction of gruels. α-amylase was extracted and partially purified from these plants using conventional methods of protein purification including ammonium sulfate fractionation and two steps of gel filtration. Purification achieved 58, 61 and 46 fold respectively for A. precatorius, B. enneandra and C. farinosa. The purified enzymes were then characterized in terms of molecular weight, optimum pH and stability, optimum temperature and stability, Km, Vmax and metals ions effects. The optimum pH of enzymes varied from 6.0 for amylases from B. enneandra and C. farinosa, to 7.0 for amylase from A. precatorius; while the optimum temperature was 60°C for amylases from A. precatorius and B. enneandra, and 65°c for amylase from C. farinosa. The three enzymes displayed, respectively for A. precatorius, B enneandra and C farinosa, a molecular weight of 60, 65 and 48.5 kDa, Km for hydrolyzing soluble starch of 3.25, 1.81 and 3.18 mg/ml, and strong individual activation by Ca 2+ , Co 2+ and Fe 3+. Li 2+ appeared as a common activator for all the amylases, while Ag + , Hg 2 + , Zn 2+ and Cu 2+ act as common inhibitors.
Oilseeds and fats, crops and lipids, Jul 1, 2006
The effect of some processing parameters (thickness of kernels, kernels to butter mass ratio, tem... more The effect of some processing parameters (thickness of kernels, kernels to butter mass ratio, temperature and duration of frying) on the acid and peroxide values and the melting properties of shea butter was studied during deep fat frying of shea kernels (Butyrospermum parkii). The results showed that the frying of kernels results in low acidic butters fulfilling commercial criteria of acidity. The increase of the frying temperature increased the peroxide value. The thermograms of butters from fried kernels dispayed a peak intermediate to both typical peaks of shea butter. The melting enthalpy of this peak increased with increasing the temperature and the duration of frying. The best frying conditions to preserve the quality of shea butter are: kernel thickness 2-6 mm; frying temperature 140-150°C, kernel to butter mass ratio 0,04-0,06 and duration of frying less than 10 minutes.
HAL (Le Centre pour la Communication Scientifique Directe), 2003
-Les cultures de tomate sont importantes dans l'Extrême-Nord du Cameroun et dans le Ouadaï au Tch... more -Les cultures de tomate sont importantes dans l'Extrême-Nord du Cameroun et dans le Ouadaï au Tchad. Les contraintes liées aux conditions de traitement et de conservation des cultures ont conduit les paysans, notamment ceux du nord-est du Tchad, à valoriser leurs productions sous forme de poudre séchée au soleil. Le produit obtenu trouve un circuit de distribution sur les marchés de N'Djamena, Maroua et Garoua. Toutefois, la qualité marchande de cette poudre de tomate reste limitée par une couleur terne et une charge élevée en impuretés. Des essais de laboratoire, menés à l'ENSAI de Ngaoundéré, montrent qu'un prétraitement des fruits, avant séchage, à 60°C pendant 12 heures dans une solution saturée de sel, ou bien pendant 20 heures dans une solution sucrée à 600 g/l, améliorent la couleur de la poudre. Ces conditions technologiques sont transférables en milieu paysan, en raison de la simplicité de leur mise en oeuvre. Les résultats obtenus offrent ainsi une opportunité de recherche appliquée pour améliorer la qualité de la poudre de tomate.
Journal of entomology and zoology studies, Mar 1, 2016
In Sub Saharan Africa, one of high potential nutritional crop is the Bambara groundnut. Popular a... more In Sub Saharan Africa, one of high potential nutritional crop is the Bambara groundnut. Popular and neglected legume, it is available in very low amount despite of being the richest seeds in lysine and methionine. To enhance the production of this crop and raise it as a strategic crop to fight hunger, the present work investigate in smallholders farms, the typology of systems of production of Bambara groundnuts in Adamawa Region of Cameroon. After 2 agricultural campaigns, storage facilities, morphotypes cultivated, storing method and protective tools to secure stored seeds were censed. Two bruchids (Coleoptera: Chrysomelidae): Callosobruchus subinnotatus (Bridwell) and Callobruchus maculatus (Fabricius), are major pests present on 10 of the 14 morphotypes of Bambara groundnuts sampled. To alleviate their damages, hazardous pesticides are currently used by producers, the possibility for developing some alternatives from local tools is discussed.
Des tranches de patate douce de 0,5 mm, 1 mm et 2 mm d'epaisseur, ont ete blanchies et/ou pre... more Des tranches de patate douce de 0,5 mm, 1 mm et 2 mm d'epaisseur, ont ete blanchies et/ou presechees, puis frites a 150 + 5 C. L'etude du comportement des tranches aux pretraitements a montre que le blanchiment a 65 C ou a 75 C est plus efficace pour l'elimination des sucres reducteurs et l'inactivation des polyphenols oxydases. Au cours de la friture, l'essentiel des echanges huile-eau s'effectue pendant les 10 ou 20 premieres secondes de friture, leur cinetique etant influencee a la fois par l'epaisseur des tranches, les pretraitements et le temps de friture. L'absorption d'huile semble cependant plus tributaire de l'epaisseur des tranches que des pretraitements. Les valeurs minimales d'huile absorbees par les tranches de 2 mm d'epaisseur laissent supposer que ces dernieres seraient plus convenables pour la production de chips de qualite. (Resume d'auteur)
Journal of applied biotechnology & bioengineering, Jan 17, 2017
TSM, Jul 1, 2019
L’eau du bassin versant de la Menoua subit de plein fouet le phénomène de pollution induite par l... more L’eau du bassin versant de la Menoua subit de plein fouet le phénomène de pollution induite par les activités anthropiques très nombreuses dans la région. L’objectif de ce travail est d’étudier l’évolution spatio-temporelle de la qualité métallique de l’eau de consommation humaine du bassin versant de la Menoua, dans le but d’évaluer son degré de pollution due aux activités anthropiques. Cela afin d’estimer le niveau de risque sanitaire que court la population exposée à sa consommation. L’analyse physico-chimique (pH, température, conductivité électrique, turbidité et oxygène dissous) et métallique (Pb, Ni, Fe, Zn et Cu) a été faite sur 132 échantillons prélevés dans 33 sites répartis durant deux saisons, dont deux campagnes en saison sèche et deux autres en saison pluvieuse. Il en ressort que les eaux ont un pH acide compris entre 5,70 et 6,02, une faible minéralisation, une conductivité comprise entre 107,85 et 146,74 μS/cm et une forte turbidité comprise entre 0,58 et 0,68 NFU. Les résultats d’analyse en métaux mettent en évidence une forte contamination en fer, compris entre 0,79 et 0,89 mg/L, avec une toxicité forte, le quotient de danger étant supérieur à 1. Les autres métaux, Pb, Zn, Cu, Ni présents dans les ressources sont révélateurs d’une pollution anthropique, mais ne constituent pas un risque pour la boisson.
Journal of experimental agriculture international, Jan 10, 2017
Journal of the Science of Food and Agriculture
BackgroundCassava processing is a crucial source of livelihood for rural farmers and processors i... more BackgroundCassava processing is a crucial source of livelihood for rural farmers and processors in Nigeria and Cameroon. This study investigated the varietal effect on the processing productivity of women farmer processors within their working environment and compared this to the field yield and the food product quality as evaluated by the processors. Field trials were established in Nigeria (Benue and Osun state) and Cameroon (Littoral zone). Eight cassava genotypes, including improved, regional, and processors' preferred checks were evaluated. Roots of these genotypes were harvested, and processed into gari and eba by processors with the time of each processing step recorded. Through pairwise ranking processors assessed the quality of the roots and food products.ResultsSuperior field performance of improved genotypes was observed over checks in Cameroon and Nigeria (Benue state) for dry matter content and fresh and dry yield. During processing, genotypes showed significant var...
Food bioscience, Apr 1, 2022
Zenodo (CERN European Organization for Nuclear Research), Sep 7, 2022
Bonagoum Men Agriculture (all), trade, transport (men) Women Agriculture (all), fishing (men), tr... more Bonagoum Men Agriculture (all), trade, transport (men) Women Agriculture (all), fishing (men), trade, hunting, breeding Bonamukandjo I Men Agriculture (all), trade, task work (mainly men from NorthWest) Women Agriculture (all), trade Passim Men Agriculture (all), breeding, task work Women Agriculture (all) Nkongsoung Long Trait Women Agriculture (all), breeding, trade Quartier 5 Men Agriculture (all), trade, breeding Women Agriculture (all), trade, breeding Distinction between farmers is generally done in two classes: wealthy and poor. Although data clearly show that there are middle farmers, it is difficult for interviewee to characterize these ones. Differences between wealth categories are in terms of land ownership, type of culture, farmed surface, and harvested quantities (table 3). In this respect Wealthy have land ownership, invest * I: Improved Variety, old released; L: Local variety; For each variety, the number of each gender in the brackets is the number of persons which have selected this variety
Bioresources and Bioprocessing, Dec 1, 2018
Background: Biosurfactants are natural surface-active compounds produced by a variety of microorg... more Background: Biosurfactants are natural surface-active compounds produced by a variety of microorganisms. The high cost of culture media limits the large-scale production and use of biosurfactants. It is therefore necessary to develop an efficient and cost-effective bioprocess to improve the yield of biosurfactants from microorganisms. In this study, the response surface method was used to optimize the production of biosurfactants by a Lactobacillus strain and the antimicrobial activity of the biosurfactants was assessed. Results: The biosurfactant-producing strain was identified as Lactobacillus paracasei subsp. tolerans N2 after 16S rRNA gene analysis. Among the different variables studied using a Plackett-Burman statistical design, temperature and peptone and sugar cane molasses concentrations were found to be the main factors that had significant (p < 0.05) influence on biosurfactant production. The results of this study showed that molasses concentration at 59.5 g/L, peptone at 6.20 g/L and temperature of 33 °C were optimal conditions for biosurfactant production, with a maximum yield of 2.70 g/L. The biosurfactant exhibited surface tension reduction of 37.85 mN/m and antimicrobial activity expressed as inhibition diameter of 63 mm. Partial characterizations by elemental, biochemical and Fourier transmission infrared spectroscopy analysis of the biosurfactant produced revealed that it was glycolipoprotein in nature. The biosurfactant exhibited bactericidal activity against Pseudomonas aeruginosa PSB2, Pseudomonas putida PSJ1, Salmonella sp. SL2, Escherichia coli MTCC 118, Bacillus sp. BC1 and Staphylococcus aureus STP1 at concentrations ranging from 6.4 to 50 mg/mL. Conclusion: The yield of biosurfactant was four-fold higher after optimization of media components and culture conditions using response surface methodology. The results of this study suggested that sugar cane molasses can be used as a low-cost substrate to enhance the yield of biosurfactants with antimicrobial activity.
Journal of the Science of Food and Agriculture
BACKGROUNDNigeria and Cameroon are multi‐ethnic countries with diverse preferences for food chara... more BACKGROUNDNigeria and Cameroon are multi‐ethnic countries with diverse preferences for food characteristics. The present study aimed to inform cassava breeders on consumer‐prioritized eba quality traits. Consumer testing was carried out using the triadic comparison of technologies (tricot). Diverse consumers in villages, towns and cities evaluated the overall acceptability of eba made from different cassava genotypes. Data from both countries were combined and linked to laboratory analyses of eba and the gari used to make it.RESULTSThere is a strong preference for eba with higher cohesiveness and eba from gari with higher brightness and especially in Cameroon, with lower redness and yellowness. Relatively higher eba hardness and springiness values are preferred in the Nigerian locations, whereas lower values are preferred in Cameroon. Trends for solubility and swelling power of the gari differ between the two countries. The study also reveals that the older improved cassava genotype...
Springer eBooks, 2022
The development and scaling out of flash-dryer innovations for more efficient, small-scale produc... more The development and scaling out of flash-dryer innovations for more efficient, small-scale production of high-quality cassava flour (HQCF) and starch is described. The diagnoses of cassava-processing SMEs (small and medium enterprises) revealed their energy expenditures for drying were considerably higher than those of large-scale industrial companies, which was mostly due to suboptimal design of flash-drying systems. As a result, small-scale production of cassava starch and HQCF often incurs high production costs, incompatible with market prices of final products. Taking stock of this situation, RTB scientists have developed several innovations to optimize energy efficiency and costs, including a longer drying pipe, reengineered heat exchanger, larger blower for higher air velocity, and a higher product/air ratio. This was based on numerical modelling to determine the key design features of energy-efficient flash dryers, followed by construction and demonstration of a pilot-scale prototype. As a result, improved small-scale flash dryers are now being scaled out to the private sector in various countries, using the Scaling Readiness framework and achieving 10-15% gains in productivity and incomes. A method for diagnosis of process efficiency is also described, to identify technical bottlenecks and to document and measure the outcomes and impacts during the implementation of scaling-out projects.
European Scientific Journal, ESJ, 2018
The health risk associated with the consumption of water polluted by humans in the World, particu... more The health risk associated with the consumption of water polluted by humans in the World, particularly in Africa, is a real public health problem. This is why WHO, from its inception in 1948, has always been concerned with defining limit values. The aim of this work was to study the physicochemical and microbiological quality of water in the Menoua watershed through a spatiotemporal dynamics to assess its degree of anthropogenic pollution and to estimate the level of risk of infection and diseases inherent in its consumption. Physicochemical analysis (pH, temperature, turbidity and dissolved oxygen) and microbiological (E-coli, salmonella and shigellas) was carried out on 132 samples taken from 33 sites distributed in two seasons, two in dry seasons and two in rainy season. The results show that these waters have an acidic pH, a low dissolved oxygen content, strong microorganism levels all correlated with high turbidity. These very high levels of microorganism, illustrate well the e...