Innovative cowpea processing practices to achieve better food sovereignty
Supervisors :Prof. M.A.J.S. van Boekel, PDQ, WU
Prof. D.J. Hounhouigan, FSA, UAC
Dr. Ir. A.R. Linnemann, PDQ, WU
Dr. Ir. M.J.R. Nout , FHM, WU
Project term :
February 2007 – September 2012
TELFUN / NUFFIC
A diet based on plant foods, as common in West Africa, is frequently deficient in minerals and vitamins. Not only the concentration but also the absorption of minerals (calcium, iron and zinc) is limiting due to, among others, phytate (IP6) and polyphenols (TPC). Moreover, processing and consumption constraints discourage the use of local foods. Therefore, improved food preparation practices, that fit the local food networks, could help to enhance their consumption. This hypothesis is investigated for cowpea (Vigna unguiculata) dishes in West Africa. Our research targets the indigenous knowledge of cowpea processing and consumption practices, the nutritional value of cowpea dishes and the improvement of traditional processing techniques to achieve a better nutritional status and thus contribute to food sovereignty in resouce-poor populations of West Africa.
AimThe research intends to:
1. characterise cowpea landraces in use in Benin with regard to nutritional, anti-nutritional and functional properties
2. determine present cowpea dishes processing practices and consumption habits, with special reference to their load of Ca, Fe and Zn
3. assess the effect of local processing methods on iron and zinc availability in cowpea dishes
4. assess the effect of traditional softeners (kanwu and sodium bicarbonate) on the amino acids composition and cookability of cowpea
5. evaluate the contribution of processing practices to the reduction of the flatulence generated by cowpea foods
ResearchObjective 1. Twenty landraces have been collected, multiplied and analysed for their chemical composition. Fe and Zn contents range from 6 to 10 and 4 to 5 mg/100g d.w., respectively. IP6 and TPC vary from 0.67 to 1.52 and 0.25 to 1.2 g/100g d.w., respectively. White landraces have lower amount of TPC than coloured ones. White landraces are genetically and functionally close.
Objective 2. In Benin, 18 cowpea dishes were reported among which two are leaves-based. A correspondence analysis revealed that three highly consumed dishes : Abobo (boiled beans), Ata (deep-fried dumplings) and Atassi (boiled rice and beans). Steeping, dehulling, milling, cooking, whipping, deep-frying, and roasting are the main processing operations, while fermentation and germination are not applied. The use of softeners (kanwu, bicarbonate) is a common way to reduce the cooking time. The long cooking time, tedious bean dehulling and flatulence are the key constraints for cowpea processing and consumption.
Objective 3. Ten cowpea dishes were collected from commercial processors and analysed for their mineral (calcium, iron, and zinc) and antinutrients composition. The only dish with an acceptable [IP6] : [Mineral] molar ratio for all targeted minerals is Adjagbé, a cowpea-leaf dish, although the TPC concentration is still high (0.91 ± 0.1 g Tannic Acid Equivalent /100g d.w.). Present traditional processing techniques do not lead to an adequate availability of iron and zinc.
Objective 4. Sodium bicarbonate induced 30% reduction in cooking time while calcium carbonate leads to 10% increase. The presence of monovalent and divalent cations strongly influence the cooking time.
Objective 5. Flatulence inducing compounds are not mainly located in cowpea hulls. Rhizopus and Bacillus fermentation reduced notably the flatus factors while lactic acid bacteria fermentations did not. Dehulling, normal cooking and cooking with softeners (kanwu and bicarbonate) do not have much effect on the in-vitro digestibility and the fermentability of cowpeas.
Future research- Effect of the use of softeners on amino acid composition
- Confirmation of the effects of processing techniques on flatulence inducing observed in vitro by in-vivo experiments.
- Suitability of selected cowpea landraces to the production of commonly consumed food needs
References1. Madode Y.E., Houssou P., Linnemann R.A., Hounhouigan D.J., Nout M.J.R and M.A.J.S. van Boekel, 2011. Production, consumption and nutritional analysis of West african cowpea dishes. Ecol. Food Nutr. 50 (2) 115-136.
2. Madode Y.E., Adofo K., Linnemann A., Nout M.J.R. Hounhouigan D.J., and van Boekel M.A.J.S. Relation between genetics, composition and functional make-up of twenty cowpea landraces cultivated in Benin. To be submitted to J. Food Sci. Agr.