Physicochemical Characterization of Banggai Yam (Dioscorea alata) Starches

Banggai is a typical yam native to Banggai Island with a large number of varieties. It functions as a source of carbohydrate, especially starch. The physicochemical characteristics of Banggai yam starch are unknown, therefore, this study aims to investigate the starch characteristics of three Banggai yam varieties namely (Baku Pusus, Baku Tuu Oloyo, and Baku Boan). The starch was extracted and analyzed for the physicochemical properties including, amylose, and amylopectin contents, granule morphology, color, pasting properties, solubility, swelling power, gel strength, and syneresis. The results showed that the wet starch extraction of Banggai yam was relatively low, i.e., Baku Pusus (8.66%), Baku Tuu Oloyo (5.09%) and Baku Boan (4.56%). Furthermore, the three varieties contained starch ranging from 88.00-88.89% which composed of amylose (60.29-62.88%) and amylopectin (25.12-28.65%). The starch granules showed ellipsoid, polyhedral, and triangular forms with lengths ranging from 17.94-23.59 mu m and widths of 13.97-16.72 mu m. The RVA profiles showed that the starches had high initial pasting temperatures (80.10-80.35 degrees C), high peak and end viscosity, experienced viscosity breakdown during the heating phase, while the cold paste had a high setback viscosity. Based on the results, Baku Pusus had the highest solubility, limited swelling power with a high gel strength, and experienced syneresis.