Physicochemical properties of starches during potato growth

The characterization of physicochemical properties of starch during potato growth is critical to the development of new starch products. Desired functional properties may be achieved by controlling the growth period, without further physical or chemical modification of the starch. In this study, starch was extracted from three potato cultivars (Shepody, Snowden, and Superior) during growth. The physicochemical properties of starches were characterized by different analytical techniques. Gelatinization and retrogradation of starches were measured using differential scanning calorimetry. Starch crystalline structure was evaluated by X-ray diffraction. Rapid viscosity analysis was employed to measure starch paste viscosity and pasting temperature. Starch obtained from potatoes with a shorter growth time had higher gelatinization temperature, pasting temperature, lower peak viscosity (half that of normal starch) and higher final viscosity (double the value of normal starch). Results indicate that physicochemical properties of starches varied among the potato cultivars, as well as growth time. Different starch granular size, phosphorous content and amylose content could be major factors influencing starch functional properties.