Abstract:Chinese yam powder was prepared by limewater immersion with fresh, commercially available Dioscorea opposita as the raw material; amylose and amylopectin were separated and purified by repeated recrystallizations using n-butanol. Using iodine ions as chromogenic agents, capillary electrophoresis was used to determine the content and ratio of amylose and amylopectin in Chinese yam starch. In this study, the use of different buffers, such as citrate-phosphate and acetate acid-acetate, was compared. The acetate acid-acetate buffer was found to be superior in the separation of amylose and amylopectin. Subsequently, the separation effects of acetate acid-acetate buffer under different pH values were compared and the electrophoretic mobilities were measured. When the pH was 4.8, the best separation effect was obtained, with an electrophoretic mobility of 15.4. Under the optimized conditions, the retention time of amylopectin and amylose was 1.8 min and 2.9 min, respectively, with pure potato amylose and amylopectin as the standards. Dioscorea opposita starch was analyzed, and the amylose content was found to be 19.49%. Repeatability and recovery experiments confirmed the suitable accuracy and precision of this method.
