Effect of different processing methods on maize, sorghum and millet flours on nutritional couscous quality consumed in the Far North region of Cameroon

Maize (Z. mays), sorghum (S.bicolor) and millet (P. miliaceum)) are staple cereal grains consumed in many part of the world as nutraceutical and for their nutritional and sensory properties. In Maroua town (Far North region of Cameroon) maize, sorghum and millet grains are the main staple food to prepare couscous, however they were subjected to various processing methods (PMs) such as soaking, crushing, grinding, sieving, roasting, fermentation and germination as well. While, still to date there was no information about their effects on couscous quality. Therefore, the present study aimed to evaluate the effect of soaking, crushing, grinding, sieving and their combination on nutritional couscous quality produced from various flours processed. Hence, starch, carbohydrates, soluble sugars (SS), fibre, proteins, amino-acids, density, water absorption capacity (WAC) and oil absorption capacity (OAC) were investigated. The results obtained showed significant (P < 0.05) effect of various PMs on couscous quality, however their effects varied in respect with cereal types used. The ash content and pH increased in most of couscous samples, while SS, fibres and starch increased in maize, sorghum and millet couscous with the exception of SS which decreased in maize (12.40–3.16 g/100 g) and sorghum (11.98–3.09 g/100 g). Carbohydrates, proteins and amino-acids increased in maize and sorghum couscous, while they decreased slightly in millet couscous. The techno-functional properties increased in maize, sorghum and millet couscous except WAC (4.07–3.53 g/g) and OAC (1.55–1.16 g/g) which decreased in millet couscous. The present study demonstrated that the effect of various PMs on couscous quality is highly significant (P < 0.05) and variations were explained by PCA (PC1 x PC2: 47.05%). The PMs such as soaking, crushing and sieving had significant (P < 0.05) effect on conscous quality, thus they can be applied in order to maximize couscous quality for potential health benefit for consumers.