Study on Effect of the Amylase Content of Sweet Potato (Ipomoea batatas Lam.) Tubers on Slurry Viscosity

Sweet potato (Ipomoea batatas Lam.) is a tuber that is widespread throughout Cameroon and highly prized by the population, who eat it using a variety of culinary techniques. It naturally contains amylases, which play a crucial role in the digestion of starch into simpler molecules (such as maltose and glucose), facilitating their absorption by the body. The aim of this article is to determine the nature of these amylases and to highlight the optimum conditions for their activity. To do this, sweet potato tubers were harvested in 3 agro-ecological zones (high savannah, high plateau and bimodal forest) in order to determine their hydrolysis capacity in a slurry. The results showed that all sweet potato tubers exhibit both α- and β-amylase activity, but in varying proportions. However, β-amylase activity was highest in all the tubers analyzed (106.65 ± 6.74 BU/g for Bafia to 543.14 ± 12.09 for Dang in the high savannah zone in the north). The viscosities of the slurries produced by cooking the different flours were very high between 20 and 30°C and moderately high at 40 and 80-90°C (before and after 60°C). As for the optimum pH for activity, the amylases contained in the sweet potato act best at a pH close to neutral (5.55 - 6.55). Measurement of the viscosity of the various slurries showed that it was the slurry made with sweet potato flour from Dang that allowed the incorporation of a large quantity of flour and gave fluid slurries up to a high proportion of flour in the same quantity of water.