Ultrasonic-Assisted Extraction and Antioxidant Activity of Polysaccharides from Lotus Leaves

The purpose of this study was to investigate the optimum ultrasonic-assisted extraction process and antioxidant activity of polysaccharides from lotus leaves.A comparison between the ultrasonic-assisted extraction and the traditional water extraction was carried out.The key factors affecting extraction efficiency and their interactions were explored based on a central composite design.The optimum conditions for ultrasonic-assisted extraction were determined as 200 W,22:1,39 min and 76 ℃ for ultrasonic power,water-to-lotus leave ratio,extraction time and temperature,respectively.The extraction yield of polysaccharides under these conditions was 4.25%,which was over 40% higher than that obtained with the traditional water extraction method,while the extraction time was shortened by 56.7% using the ultrasonic-assisted extraction method.Moreover,antioxidant polysaccharides with significantly higher activity were obtained from ultrasonic-assisted extraction.