Effects of Fermentation, Germination, Roasting and Mono-Screw Extrusion Cooking on the Phytate and Iron Contents of Millet Souna Produced in Senegal (Pennisetum Glaucum)

Millet is one of the most widely consumed cereals in Senegal and in terms of the country’s grain production volume, it ranks second after rice. It is a high energy cereal but also contains a lot of nutrients such as minerals. However, millet contains anti nutritional factors such as phytates which form insoluble complexes with iron and zinc, thus reducing their bioavailability for the body. During millet processing, artisanal units, unknowingly, use methods that are known to reduce phytic acid levels. That is why, we have chosen three of these methods (germination, fermentation, roasting) and evaluated their effects on phytic acid content of millet. The results of these methods are compared to those of single-screw extrusion cooking. They show that the phytates content of raw millet is 7.56 mg / g. The different applied treatments all give reductions of the phytates contents. Thus, the highest reduction rates are obtained for 72 hours of germination with 62% of reduction of phytates, followed by extrusion cooking at 120° C which is 48.42%. Then, come respectively fermentation at 24 hours and roasting at 120° C which give respectively 44.05%, 34.89% of reduction. Whether wet or thermal methods, the degradation of phytates increases when the treatment time increases or when the temperature increases. For the iron, the contents pass from 7.56 mg / 100g in the untreated sample to 4.48 mg / 100g after roasting at 120° C. The fermentation at 24 hours and the extrusion cooking at 120° C respectively come with 7.55 and 6.80 mg / 100, while the germination causes a small increase in the iron content which goes from 7.56 to 8.13 mg / 100gs Received: June 03, 2019; Accepted: June 25, 2019; Published: July 11, 2019 *Corresponding author: Mamadou Salif Sow, Institut de Technologie Alimentaire (ITA), Hann-Dakar BP 2765, Senegal, E-mail : sowmamadou-