No abstract

Tea polysaccharide is a kind of acid glycoprotein complex extracted from tea. Tea polysaccharide has a variety of biological activities, especially the hypoglycemic effect is outstanding. It is good for human health. Tea polysaccharides have been extensively studied over the past few decades. The advantages and disadvantages of water extraction, enzyme-assisted extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and supercritical fluid extraction were described. At the same time, the structure and biological activity of tea polysaccharide were also summarized. The development of tea polysaccharide was prospected.

Pueraria lobata polysaccharides (PLPs) were obtained by a hot water extraction method. Starting from the single factor experiment, the extraction was optimized by response surface methodology, and the following optimal extraction parameters were obtained: the extraction temperature was 84 °C, the liquid−solid ratio was 11 mL/g, the extraction time was 73 min, and the extraction rate of polysaccharides was 8.59%. The Sevag method was used to remove the protein soluble in water and H 2 O 2 was used to remove the pigment; then PLPs were precipitated with three times of anhydrous ethanol, soluble salts and other small molecules were removed by dialysis, and finally refined PLPs were obtained by freeze-drying.

Pueraria lobata polysaccharides (PLPs) were obtained by hot water extraction using Pueraria lobata as raw material. Structural analysis revealed that PLPs may have a repetitive backbone units of !4) -α-D-Glcp (1!4-α-D-Glcp (1!. Phosphorylated Pueraria lobata polysaccharides (P-PLPs), carboxymethylated Pueraria lobata polysaccharides (CM-PLPs) and acetylated Pueraria lobata polysaccharides (Ac-PLPs) were obtained by chemical modifications of PLPs, respectively. The physicochemical properties and antioxidant activities of these four Pueraria lobata polysaccharides were studied in comparison. In particular, the clearance rate of P-PLPs exceeded 80 %, and was expected to achieve the same effect as V c . The results showed that the effects of different chemical modifications on the antioxidant activity of PLPs varied greatly.