Physicochemical Properties and Molecular Structure of Starches from Potato Cultivars of Different Tuber Colors

Potato plays an important role for starch resource and has diverse colored tubers because of diverse genotype backgrounds. However, it is unknown whether starch physiological and structural properties are dependent on the color of tuber. In the present study, six potato cultivars are grown under the same conditions. Though granule size (D-50, 31.33-39.47 mu m) and amylose content (29.91-36.66%) of starches from different varieties show significant (p <= 0.05) differences, but all exhibit similar morphology and B-type crystalline structure. The molecular weight of amylose and amylopectin ranges from 5.47 x 10(4) to 71.50 x 10(4) g mol(-1) and from 121.44 x 10(5) to 141.09 x 10(5) g mol(-1), respectively. The distributions of amylopectin chain length, thermal, and digestive properties differ among potato starches from six different varieties. The cluster analysis based on starch physiological and structural parameters shows that starch properties of potatoes are independent of the color of tuber but are determined by the variety genotype background. These results can provide a structural basis for quality breeding and targeting future utilization of different colored potato varieties.