Optimization of the ultrasonic-assisted enzymatic extraction of polysaccharides from Dendrobium offcinale Kimura et Migo and bioactivity study

Ultrasonic-assisted enzymatic extraction (UAEE) technology was employed to extract the polysaccharides from Dendrobium offcinale Kimura et Migo (D. offcinale). The extraction conditions were optimized by central composite design (CCD) found in the response surface methodology (RSM). The polysaccharide yield (34.05 +/- 1.03%) was well matched with the predicted value, as obtained under the optimum parameters: enzyme activity of 2040 U/g, a liquid-solid ratio of 71 mL/g, and a time of 84 min. Compared to other extraction methods, UAEE was able to yield D. offcinale polysaccharide (DOP) highly efficiently in a shorter extraction time period and at a lower extraction temperature. The extracted polysaccharide (DOPUAEE) showcased a better nitrite scavenging ability, a high antioxidant activity, and more potency in inhibiting alpha-glucosidase, expanding its versatility in food applications.