Influence of Mechanical Shelling on the Microbiological and Physico-Chemical Quality of Souna Millet (Pennisetum glaucum) and its Derivatived

Souna millet (Pennisetum glaucum) is used in Senegal for human consumption after primary processing to obtain flour and semolina. Mechanical shelling and dry milling of local cereals results in processed products with a long shelf life. The objective of this work is to study the influence of mechanical shelling on the microbiological and physico-chemical qualities of Souna millet and primary products, flour and semolina. The results of the physico-chemical analyses revealed a reduction in the content of the various parameters studied. However, the greatest losses were obtained on flour fatty acidity with 50% and on millet ash with 55% while the reduction in protein content only varied from 12% to 15% for millet and flour respectively with 14% for semolina. The percentages of reduction of calcium (14.6%), zinc (23.3%) and potassium (18.4%) contents obtained after shelling, were more important on millet, while the highest losses of iron and magnesium composition were noted respectively in flour with 18.1% and in semolina with 15.3%. At the same time, the results of microbiological analyses showed a decrease in the level of contamination of husked millet and derived products by aerobic mesophilic flora at 30°C, by yeasts and molds and by thermotolerant coliforms. An absence of Salmonella was also noted in all samples as well as Bacillus cereus, Staphylococcus aureus and E. coli were not enumerated.