Enhancing starch hydrolysis in sweet potato (Ipomoea batatas (L.) Lam.) through CaCl2 solution mashing: insights into endogenous amylase activity

Abstract

Sweet potato (Ipomoea batatas (L.) Lam.) is a tuber root crop with high economical potential and China is responsible for harvesting roughly 70% of the world production. It is relatively easy to cultivate and has high nutritional value, including fiber, vitamins, starch and sugars. Cooking the roots results in deep changes of the carbohydrate profile due to the presence of active endogenous amylases. The objective of the present study was to evaluate the influence of CaCl₂ mashing at different temperature-time conditions on the starch hydrolysis by endogenous amylases of sweet potato in order to suggest potential industrial applications. Three thermal treatments were performed with the aid of a Rapid Visco Analyzer (RVA), which allowed programming temperature-time profiles. After the treatments, the sugar analysis was carried out by high performance liquid chromatography (HPLC). Total starch content was measured in the insoluble residue from the hydrolysis and the hydrolysis efficiency was calculated. The results have demonstrated that the presence of CaCl₂ enhanced enzyme activity, resulting in higher sugar yields when compared to hydrolysis conducted without CaCl₂. The results from the present study are promising to the use of sweet potato to produce bioethanol, maltose syrup and vinegar.