Résumé
Gari, a cassava traditional product, is a key staple food in several western African countries. It is a type of dried particle semolina made through successive operations such as peeling, grating/rasping, fermentation/pressing, sieving, and roasting (cooking/drying). In Benin, there is a large variability of gari products, defined by a large range of particle sizes, homogeneity, colour, sour taste, and texture (crispiness and swelling), depending on the process. Rasping, fermentation, pressing and roasting operations were identified as key steps on technological and sensory properties of gari. Five main types of gari (Sohia, Ahayoe, Sohui, Missé, Djeffa) made with variable processes were identified. In this study, the process, and its variants according to the gari type, was precisely described. Data were collected for each unit operation, in view of assessing process efficiency and consequently, the potential to improve sustainability of gari processing. Production capacity was limited by the peeling operation, which was carried out manually (30 kg of roots/hour/worker). Cooking was the second slowest operation, also involving drudgery with exposure to heat and smoke. Energy use for cooking/drying was high, with 0.9-1.0 kg of wood/kg of gari, i.e. 13-16 MJ/kg of gari. Significant losses occurred during peeling and pressing operations (25-35% and 20-30% of root dry matter respectively). Mass balances pointed out low process yields, with only 15-25% (d.b.) of cassava roots ending in the final gari product. Losses of raw materials and energy were significant and might impact on both production costs and the environment. Moisture contents of gari ranged between 3 and 8%, which ensures a long product shelf-life. Average particle size varied from 0.5 to 0.8 mm. Particle size distribution was a key factor related to consumption way and consumer preferences in the different regions of the study. (Résumé d'auteur)