Les tubercules

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Les tubercules sont une source de nourriture importante dans de nombreuses régions d’Afrique. Selon les estimations de la FAO, les racines et les tubercules représentent 20% des calories consommées en Afrique subsaharienne, et leur demande devrait augmenter au cours des deux prochaines décennies en raison de l’urbanisation croissante. Les tubercules comme le manioc, l’igname et la pomme de terre sont essentiels à la sécurité alimentaire et à la génération de revenus. Les tubercules sont produits pour la consommation humaine et animale, mais aussi pour de nombreuses applications industrielles dans les industries alimentaires, textiles, papetières, pharmaceutiques et autres.

Les défis actuels liés à la production de tubercules comprennent la gestion des ravageurs et des maladies, la conservation des racines, la salubrité des aliments (libération possible de cyanure) et l’adaptation des nouvelles variétés sélectionnées à des fins alimentaires et industrielles. Les croissances futures de la consommation de tubercules en Afrique dépendront des progrès réalisés dans la transformation des tubercules en diverses formes alimentaires, ou de leur utilisation comme alternative au blé importé, au riz et à l’amidon de maïs pour cibler les consommateurs urbains.

Oluwatoyin Ayetigbo, Sajid Latif, Adebayo Abass, Joachim Müller. 2019. Preparation, optimization and characterization of foam from white-flesh and yellow-flesh cassava (Manihot esculenta) for powder production. Food Hydrocolloids (97)

Cassava foam, another form in which cassava may potentially be used as food, was produced from the pulp of
yellow-flesh and white-flesh cassava varieties by whipping with foaming agent (20 %w/w glycerol monostearate
colloid, GMS) and stabilizer (sodium carboxymethyl cellulose, NaCMC). Cassava foaming was optimized for
concentration of foaming agent, stabilizer and whipping time. Using Box-Behnken experimental design, two
responses were measured: foam expansion (FE, %) and foam density (FD, g/mL). White-flesh cassava pulp required
14.97% GMS, 0.51% NaCMC and 2.07 min to give a foam of 52.63% expansion and density of 0.75 g/mL.
Yellow-flesh cassava pulp required 14.29% GMS, 0.6% NaCMC and 2 min to yield a foam of 48.25% expansion
and density of 0.76 g/mL. Predicted optimal FE and FD were 54.9% and 0.73 g/mL for white-flesh cassava foam,
and 49.86% and 0.73 g/mL for yellow-flesh cassava foam, respectively, and are close to validated values. The
optimal foams were quite stable after 4 h at 25 ± 2 °C, with low volume collapse of 1.79% and 1.26% for white
and yellow cassava foams, respectively. The optimal cassava foams were dried into foam powder. There was
significant difference in color values (L*, a*, b*, C*, E*, H*, % W, Eyellow white) and total carotenoids content of
pulp, optimal foam, and powder of both varieties. Microstructure analysis of the optimal foams revealed round
air bubbles and positive skewed distribution of bubble sizes. Foaming and drying significantly reduced total
cyanogenic potential in cassava, and may be considered as processing operations capable of reducing cyanogenic
potential in cassava considerably.

Show details Posted by : MSc. Ayetigbo Oluwatoyin Elijah

Oluwatoyin Ayetigbo, Sajid Latif, Adebayo Abass, Joachim Müller. 2019. Osmotic dehydration kinetics of biofortified yellow-flesh cassava in contrast to white-flesh cassava (Manihot esculenta). Journal of Food Science and Technology

In recent times, the cultivation, processing and
consumption of biofortified yellow-flesh cassava is of
significant interest to breeders and food processors due to
its relatively high pro-vitamin-A content, compared to the
conventional white-flesh cassava. In light of this, osmotic
dehydration (OD) kinetics of a recently released biofortified
yellow-flesh cassava was compared to that of a whiteflesh
cassava, using salt, sugar, and salt–sugar solutions at
different temperatures (30, 45, 60 C) and fixed cube/solution-
ratio. Water loss (WL) and solids gain (SG) data
were fitted by non-linear regression using four models
(Page, Weibull, Azuara, and Peleg). Azuara model was
most appropriate in describing OD kinetics for both cultivars.
Azuara estimates for equilibrium WL and equilibrium
SG, respectively, ranged between 0.101–0.120 and
0.049–0.094 g/g for salt solution, 0.158–0.212 g/g and
0.107–0.268 g/g for sugar solution and 0.234–0.306 g/g
and 0.189–0.276 g/g for salt–sugar solution. The best
conditions for OD of both cultivars by salt solution and
sugar solution was at 60 C and 45 C, respectively, while
that for salt–sugar solution varied with cultivar. Increasing
temperature increased water loss and solids gain. Salt-OD
conformed to Arrhenius temperature dependence of diffusivity,
but sugar-OD and salt–sugar-OD did not. Micrographs
reveal biofortified yellow-flesh cassava was more susceptible to cell wall collapse than white-flesh cassava.
Extent of dehydration by OD agents ranked: salt–sugar[
sugar[salt. Osmotic dehydration may be useful as a
means of dehydration for cassava prior to drying, and is
especially relevant for the carotenoids-rich biofortified
yellow cassava.

Show details Posted by : MSc. Ayetigbo Oluwatoyin Elijah

Latif Sajid, Müller Joachim. 2015. Potential of cassava leaves in human nutrition: A riveiw. Trends in Food Science & Technology

Cassava is mainly grown for its root tubers whereas its leaves are mainly considered as a byproduct. However, cassava leaves are a rich source of roughage, protein, minerals, and vitamins. But, the presence of anti nutrients and cyanogenic glucosides are the major drawbacks in cassava leaves which limit its human consumption. These anti-nutrients and toxic compounds of cassava leaves cause various diseases depending on the consumption level. Hence these anti-nutrients and toxic potential of cassava leaves should be addressed during cassava leaf processing (CLP) before human consumption. Several CLP methods have been developed but every method has its own limitations. Some CLP methods successfully detoxify cassava leaves but simultaneously destroy the nutrients. Efforts have also been made for cassava leaf protein extraction in the form of cassava leaf protein concentrate (CLPC) but protein recovery was very low. This review summarizes the nutrient, anti-nutrient and toxic composition of cassava leaves, CLPC, different CLP methods, human consumption and diseases caused by cassava leaves. Furthermore, recommendations have been made in order to encourage cassava leaves consumption as an important source of protein and micro-nutrients.

Show details Posted by : Arthur

Akinwale T E, Niniola D M, Abass A B, Shittu T A, Adebowale A A, Awoyale W, Awonorin S O, Adewuyi S, Eromosele C O. 2017. Screening of some cassava starches for their potential applications in custard and salad cream productions. Journal of Food Measurement and Characterization

Custard powder and salad cream are two food products commercially manufactured using different quantities of corn starch. This study aimed at determining the physicochemical properties of some starches extracted from some white and yellow root cassava varieties. The
prospective applicability of the cassava starches in custard powder and salad cream production was also determined. The physical, chemical and functional properties of eight cassava starches were determined using standard analytical procedures. Sensory acceptability of the products was also determined using untrained consumer group. Products made from corn starch were used as the reference samples. The physical, chemical and functional properties of the cassava
starches varied significantly (p < 0.05). The results of multivariate data analysis (principal component and cluster analyses) showed that it was difficult to completely discriminate starches from the yellow fleshed and white fleshed cassava roots. Texture was the most important sensory attribute determining the two products’ acceptability. Starch powder dispersibility was found to have significant influence (p < 0.05) on the sensory acceptability of the two
products. However, starch from a yellow fleshed root (TMS 01/1368) was the most preferred for salad cream making while starch from a white fleshed root (TMS 30572) was the most preferred for making custard powder. The starches showed high potential to replace corn starch for the respective product manufacture.

Show details Posted by : Arthur

Callo-Concha Daniel, Ewert Frank. 2014. Using the Concepts of Resilience, Vulnerability and Adaptability for the Assessment and Analysis of Agricultural Systems. Change and Adaptation in Socio-Ecological Systems, Volume 1, Issue 1, ISSN (Online) 2300-3669

Resilience, vulnerability and adaptability have emerged as dominant concepts in the study of disturbance and change of social-ecological systems. We analyze the conceptual, methodological and operational aspects in using these concepts for the assessment and analysis of agricultural systems and try to identify differences and possible overlaps between them. The analysis is performed considering a number of published studies on agricultural systems over a wide geographical range where these concepts have been applied. Our results show a clear conceptual overlap and often the exchangeable use of the concepts. Furthermore, the driving methodological and operational criteria for their application could not be separated unambiguously. It was, thus, difficult to identify guiding principles for the operational application of the individual concepts. We stress that the operationalization of these concepts requires consistency in the approaches and protocols to ensure their coherent use. We also argue that the conceptual and operational integration of resilience, vulnerability and adaptability would perhaps lead to a more complete portrayal of the behavior of agricultural systems in changing situations. But this requires more research including the development of operational protocols for which the premises of complexity, participation and functionality seem key.

Show details Posted by : Arthur

Ayetigbo Oluwatoyin, Latif Sajid, Abass Adebayo, Müller Joachim. 2018. Comparing Characteristics of Root, Flour and Starch of Biofortified Yellow-Flesh and White-Flesh Cassava Variants, and Sustainability Considerations. Sustainability: Special Issue Advances in Food and Non-Food Biomass Production, Processing and Use in Sub-Saharan Africa: Towards a Basis for a Regional Bioeconomy

Cassava is a significant food security and industrial crop, contributing as food, feed and industrial biomass in Africa, Asia and South America. Breeding efforts have led to the development of cassava variants having desirable traits such as increased root, flour, and starch yield, reduced toxicity, reduced pest/disease susceptibility and improved nutrient contents. Prominent among those breeding efforts is the development of colored-flesh cassava variants, especially biofortified yellow-fleshed ones, with increased pro-vitamin A carotenoids, compared to the white-flesh variants. The concept of sustainability in adoption of biofortified yellow-flesh cassava and its products cannot be fully grasped without some detailed information on its properties and how these variants compare to those of the white-flesh cassava. Flour and starch are highly profitable food products derived from cassava. Cassava roots can be visually distinguished based on flesh color and other physical properties, just as their flours and starches can be differentiated by their macro- and micro-properties. The few subtle differences that exist between cassava variants are identified and exploited by consumers and industry. Although white-flesh variants are still widely cultivated, value addition offered by biofortified yellow-flesh variants may strengthen acceptance and widespread cultivation among farmers, and, possibly, cultivation of biofortified yellow-flesh variants may outpace that of white-flesh variants in the future. This review compares properties of cassava root, flour, and starch from white-flesh and biofortified yellow-flesh variants. It also states the factors affecting the chemical, functional, and physicochemical properties; relationships between the physicochemical and functional properties; effects of processing on the nutritional properties; and practical considerations for sustaining adoption of the biofortified yellow-flesh cassava.

Show details Posted by : Arthur

Awoyale Wasiu, Abass Adebayo B, Ndavi Malu, Maziya-Dixon Bussie, Sulyok Michael. 2017. Assessment of the potential industrial applications of commercial dried cassava products in Nigeria.. Journal of Food Measurement and Characterization

Variations in the functional and pasting properties of four groups of commercial dried cassava product in Nigeria were evaluated in this study, to explore their potential for use as industrial raw materials. In total, 692 products were analyzed using standard analytical methods. The functional and pasting properties of the samples were found to vary significantly (p < 0.05). Toasted cassava was found to have the highest water absorption capacity, at 467.42 %, and dried cassava the lowest, at 252.57 %. Conversely, dried cassava was found to have the highest peak and breakdown viscosities, and toasted cassava the lowest. A significant (p < 0.01) positive correlation was found to exist between dispersibility and the swelling power (r = −0.93) and solubility index (r = −0.84) of the cassava products. Meanwhile, the correlation between dispersibility and the peak (r = −0.75) and breakdown (r = −0.72) viscosities was positive and significant (p < 0.05). Therefore, the authors of this study conclude that user industries such as the food, paper, adhesives, textiles and plywood sectors might require information on the pre-processing of cassava-based feedstock, so as to predetermine the technical usability of such raw materials within their industrial processes.

Show details Posted by : Arthur

Malabo Montpellier Panel.2018.Mechanized: Transforming Africas Agriculture Value Chains.Dakar.

The current report—Mechanized: Transforming Africa’s Agriculture Value Chains—summarizes the findings of a systematic analysis of what countries at the forefront of progress in mechanization have done right. It analyzes which policy decisions were taken and which interventions were implemented to substantially increase the uptake of mechanization. The report takes a broad perspective on mechanization, including technologies along the entire value chain and how they relate to agricultural development and job creation.
Show details Posted by : Jelana Vajen

Adu-Gyamfi Poku, Regina Birner, Saurabh Gupta. 2018. Is Africa ready to develop a competitive bioeconomy? The case of the cassava value web in Ghana. Journal of Cleaner Production (200): 134-147 pp.

The increasing global demand for diverse biomass-based products such as food, feed and fuel can
transform African agriculture from a food-supplying to a biomass-supplying and processing sector in the
growing international bioeconomy. This study addresses the requisite policy and institutional environment
needed to foster the development of a competitive and sustainable bioeconomy in Africa. The
paper uses the case of cassava in Ghana for an empirical case study. The novel concept of biomass-based
value webs, that is, interlinked agricultural value chains, is combined with Porter’s Diamond model to
analyse the extent to which Ghana is positioned to develop a competitive cassava value web. Empirical
data collection involved mapping the physical biomass flows, applying the ‘Net-Map’ tool to identify all
the actors in the emerging value web and their linkages, as well as in-depth interviews with the identified
actors. The study finds that despite the huge opportunities for cassava biomass in Ghana, there are
coordination problems between farmers, processors and industrial end-users. This has hindered the
potential for increased cassava production, processing and utilisation. There is also generally a lack of
private sector initiatives in the development of new cassava based products. Accordingly, industrial endusers
tend to depend on imported alternatives. Unsuccessful government initiatives and the absence of
legislation such as a composite flour policy or a biofuel blend policy have also been major contributing
factors to the unrealised industrial potential of cassava in Ghana. The findings therefore suggest that
competitive cassava utilisation in the emerging bioeconomy hinges on stronger institutional linkages
between value web actors and government support mainly in the form of local content policies that
encourage the use of cassava based products.

Show details Posted by : Dr. Adu-Gyamfi Poku