Biochemical changes in cassava products (flour & gari) subjected to Saccharomyces cerevisae solid media fermentation

Abstract

In an attempt to enhance the nutritional quality of cassava products (flour and gari), Saccharomyces cerevisae was used in the fermentation (solid media) of cassava pulp. The mash obtained was subsequently processed into flour and gari, the forms in which cassava products are popularly consumed in Nigeria. These products were analysed with regard to proximate composition, mineral composition and antinutrient content. The result revealed that there were significant increases in the protein [flour (10.9%), gari (6.3%)] and fat [flour (4.5%), gari (3.0%)] contents. Conversely, there were significant decreases in the cyanide content [flour (9.5 mg/kg), gari (9.1 mg/kg)], carbohydrate [flour (77.9%), gari (84.5%)] and mineral (Zn, Mg, Fe, Ca, Na and K) contents of the cassava products, except in the fermented gari where there was significant increase in the Mg and Fe contents. However, Saccharomyces cerevisae fermentation of the cassava did not bring about any significant changes in the tannin, crude fibre or ash contents of the cassava products. Heavy metals, such as Cu, Ni and Pb, were not detected in either the fermented or unfermented cassava products. Furthermore, nutrient increase was higher in cassava flour while the antinutrient decrease was higher in gari. It could be inferred that Saccharomyces cerevisae, a cheap and non-pathogenic saprophytic aerobe, could be used for enhancing the nutritional potential of cassava products by increasing nutrient (protein and fat) and decreasing cyanide contents.