A comparison study on microwave-assisted extraction of Potentilla anserina L. polysaccharides with conventional method: Molecule weight and antioxidant activities evaluation

The conventional extraction methods for polysaccharides were time-consuming, laborious and energy-consuming. Microwave-assisted extraction (MAE) technique was employed for the extraction of Potentilla anserina polysaccharides (PAPMAE), which is a traditional Chinese functional food. The extracting parameters of PAPMAE were optimized by Box–Behnken design. The optimum conditions were ratio of water to raw material 14.5:1, microwave power 369 W, extraction temperature 63.3 °C and extraction time 76.8 min with an enhanced yield of 13.33%. In microwave heating process, a sharp decrease in Mw was detected in SEC-LLS measurement. A df value of 3.03 indicated that PAPMAE exhibited a compact hard sphere conformation in an aqueous solution. Furthermore, it showed stronger antioxidant activities compared with hot water extraction by evaluating in superoxide radical (O2-), hydroxyl radical (OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, reducing power and metal chelating assay. The data obtained clearly showed that the molecular weights played a more important role in antioxidant activities.