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Retting, a spontaneous and traditional fermentation of cassava roots in Central Africa, was optimised in terms of time and the quality of the endproduct. Optimal conditions were achieved by using an experimental research methodology. Temperature is the most influential factor, with an optimum of 34°C for quicker retting. The roots should be peeled and soaked in water immediately after harvesting to increase the quality of cassava foods. Inoculation of water with juice from a prior retting helps in cassava detoxification but has no influence on the time or the quality of foo-foo. Foo-foo samples had the most favourable organoleptic quality when an incubation temperature of between 28 and 37°C was used. Using optimal conditions, retting time was reduced 3-fold, and foo-foo of high and constant quality could be processed.

Hot water-insoluble cell wall polysaccharides of immature and mature Dioscorea dumetorum and D. rotundata yam tubers have been characterized in enzymatically destarched flours and were mainly constituted of cellulose followed by hemicellulosic polymers of xylose, galactose, mannose and arabinose. Immature tubers of both species contained a higher proportion of cell wall carbohydrates than mature ones essentially because of their low starch content. Storage of mature tubers of both species induced an increase of cell wall polysaccharides content particularly for D. dumetomm. The strong hardening of D. dumetorum yam during storage was characterized by the deposition of a xylose-containing polymer and of additional cellulose and by the lignification of the tubers.