13 sep 2006 13:30
Onderdeel:
Wageningen Universiteit
Locatie:
Aula, gebouw 362, Gen. Foulkesweg 1, Wageningen
Organisatie:
Wageningen Universiteit
Promotor:
prof.dr.ir. M.A.J.S. van Boekel (Productontwerpen en kwaliteitskunde)
Co-Promotor:
Dr.ir. M.J.R. Nout, Dr.ir. A.R. Linnemann
This thesis focuses on the diversity of sorghum and its post-harvest processing into food. We studied the contribution that sorghum can make to Fe and Zn intake by poor people in Africa, using the situation in Benin as a study context.
The culinary and sensory characteristics of sorghum crops and their derived foods in northern Benin were surveyed. Three food categories were identified: pastes, porridges, and beverages. We distinguished more than 100 farmers’ varieties.
A genome fingerprinting technique (AFLP) was used to cluster these farmers’ varieties into 45 distinct genotypes which were analyzed for their phytate content and Fe and Zn concentration and in vitro solubility. Seven of the identified genotypes contain adequate in vitro soluble Fe to meet consumers’ requirements.
The impact of the local sorghum processing technologies on phytate, phenolics and Fe and Zn in vitro solubility was evaluated. Wet cleaning of sorghum grain, germination and fermentation are the most effective process operations to degrade phytate and phenolics and to increase the solubility of Fe and Zn.
A mathematical model used to study the effect of processing variables on Fe and Zn solubility suggests that maximum mineral in vitro solubility in sorghum can be achieved, by processing the grains with combined germination and fermentation. Such combinations would enable the preparation of infant cereal porridges with improved nutrient contents.