Physicochemical, Pasting and Thermal Properties of the Starch of Three Varieties of Yam (Dioscorea spp.) as Potential Food Ingredients

Yam starch accounts for 70–80% of its dry matter, and its physicochemical and technofunctional properties are crucial for its use in the food industry (gelling agent, thickener, and stabilizer). The objective of this study focuses on the physicochemical, pasting and thermal properties of starch extracted from the yam varieties Dioscorea cayenensis, Dioscorea alata, and Dioscorea rotundata. The proximal composition, amylose and amylopectin content, as well as their functional properties (absorption index, solubility, swelling, thermal and pasting behavior, morphology, and color) were analyzed. The results showed that the starch extraction yield varied between varieties, being highest in D. cayenensis with 14.14%. D. alata had the highest starch (82.24%) and amylose (34.69%) content, which gives it greater gel firmness and retrogradation potential, as well as the best techno-functional properties water absorption index (2.46 g/g), water solubility index (1.1%), and swelling power (2.54 g/g). D. cayenensis stands out for its high amylopectin content (69.62%) and brightness (96.89), reflecting greater starch whiteness. D. rotundata has an intermediate balance between amylose and amylopectin, which makes it versatile. The proximal composition and techno-functional properties of yam starch position it as a promising raw material for the food industry, especially in the manufacture of thickeners, gelling agents, and in bakery products, pasta and noodles.