Comparison of Carbohydrate and Pasting Profile of Sweet Potato (Ipomoea batatas L. Lam) Flour from Three Agro-Ecological Zones in Cameroon

Abstract

Processing sweet potato tubers into flour is the most common way of making a variety of food products, particularly in traditional cooking, baking and pastry-making. However, this flour can also be used in baby food to prepare porridges. The present work highlights a comparative study of the carbohydrate potential of sweet potatoes from three agro-ecological zones that constitute the tuber's production basins in Cameroon in regards of an improved variety. The tubers were processed into flour after peeling, washing, slicing, drying and sieving. Different carbohydrate compounds contents were determined through various classical methods (starch and its two compounds: amylose and amylopectin; total sugars, maltodextrins, reducing sugars, sucrose, free glucose, free fructose, free galactose, raffinose and dietary fibers). After that, viscosimetric properties and sweetness index were also determined in sweet potato flour. Results showed that tubers harvested in the High Savannah zone (Dang) has a high starch content compared with the other two. However, the sweet potato from the High Plateaux zone showed intermediate values. However, tubers harvested in the Bimodal Forest zone (Bafia) showed high levels of amylose, soluble carbohydrates, sucrose, fructose and crude fiber. Measurement of the viscosity of starch stacks shows that this parameter varies from 1.49 Pa.s for sweet potatoes harvested in Bafia to 3.49 Pa.s for sweet potatoes from Dang (High Savannah). This leads us to conclude that the tubers from Bafia (Bimodal Forest zone) are more suitable for confectionery-type food products, whereas those harvested in the High Savannah zone are better suited to the preparation of porridges for young children.