Method for extracting dendrobium polysaccharides through subcritical water

The invention discloses a method for extracting dendrobium polysaccharides through subcritical water and belongs to the field of extraction of natural active ingredients. The method comprises the following steps: smashing, degreasing and drying dendrobe raw materials, then placing the processed materials in a subcritical water extracting device, extracting for 1-3 times and for 5-30 min under the conditions that the temperature is 100-160 DEG C, the pressure 0.5-2.0 MPa, and the liquid-solid ratio of subcritical water to dendrobe powder is 15-45 mL/g; collecting an extracting solution, adding absolute ethyl alcohol, performing standing, and performing centrifugal separation to obtain precipitate which is a crude product; washing with absolute ethyl alcohol, acetone and ethyl ether to obtain the dendrobium polysaccharides. According to the invention, the advanced subcritical water extracting technology is adopted to extract the dendrobium polysaccharides, the extracting time is short, the extracting efficiency is high, and the obtained dendrobium polysaccharides has remarkable antioxidant activity. The method is environment-friendly and free of pollution, has low requirements to equipment, and facilitates industrial production.