Effect of Low Temperature Storage on Physicochemical Properties of Starch Isolated from Cultivars of Potatoes with Various Characteristics

Abstract

Ten cultivars of potatoes called tasting potatoes (Andes Red, Inkanomezame, Sherry, Jaga Kids Purple, Cynthia, Tawara Murasaki, Destroyer, Tokachi Kogane, Violetta and Yodel) that were collected from different areas of the world were cultivated in Aomori to be adapted to a Japanese climate. After harvest, the potatoes were stored for 2 and 7 months at 2°C. This study examined physicochemical properties of starches isolated from these potatoes and investigated the effects of the low temperature storage. The starch properties determined in this study were particle size distribution, X-ray diffractography, pasting properties using a Rapid Visco Analyzer (RVA), thermal properties using differential scanning calorimetry, the contents of phosphorus and amylose, swelling power, solubility, digestibility by pancreatin and observation using scanning electron microscopy. Starches from tasting potatoes showed type B X-ray diffraction patterns, and the patterns were not affected by increasing the duration of the storage period under low temperature. Setback by RVA, digestibility by pancreatin and the contents of amylose tended to increase during the storage. But the other physicochemical properties changed variously and inconsistently with the cultivars or the places of origin.