Effects of extraction methods on physicochemical properties and hypoglycemic activities of polysaccharides from coarse green tea.

Coarse tea is made of mature tea plant (Camellia sinensis L.) shoots and is generally discarded as a worthless crop product, but has been proved an excellent material for the treatment of diabetes. This study aims to evaluate the effects of the extraction techniques WE (water extraction), UAE (ultrasound-assisted extraction), MAE (microwave-assisted extraction), and EE (enzyme extraction) on the physicochemical properties and antidiabetic activities of polysaccharides from coarse tea (CTPSs). The results showed that all four CTPSs had homogeneity in the monosaccharide types and similar IR (Infrared spectroscopy) characteristic absorption peaks, but differed in monosaccharide proportion and molecular weight distribution. Compared with the other three extraction techniques, CCTPS extracted by EE had the lowest protein content, the highest total sugar content of 71.83% and a polysaccharide yield of 4.52%. In addition, EE-CTPS had the best hypoglycemic activity that was better than ordinary green tea polysaccharides, the α-glucosidase and α-amylase inhibitory activities of EE-CTPS were highest in the range of 2-10 mg/mL compared with the other three CTPSs, which may be related to its smaller molecular weight and porous structure. The results suggested that the EE method was a good way to extract polysaccharides from coarse tea for food and pharmaceutical production.

Emulsifying Properties of Polysaccharide Conjugates Prepared from Chin-Brick Tea.

Chin-brick tea polysaccharide conjugates (TPC-C) were prepared to study their emulsion capabilities. Interfacial tension and the effects of some factors, such as storage time, metal ion concentrations (Na+, Ca2+), pH (2.0-8.0), and heat treatment (70-100 °C) on the emulsions stabilized by TPC-C were studied. The interfacial tension of TPC-C (10.88 mN/m) was lower than that of gum arabic (15.18 mN/m) at a concentration of 0.08%. As the TPC-C concentration increased from 0.1 to 3.0 wt %, the mean particle diameter (MPD) (d32) of emulsions stabilized by TPC-C decreased from 1.88 to 0.16 µm. Furthermore, at a concentration of 0.5 wt % or higher, the MPD (d32) of emulsions stabilized by TPC-C at 25 and 60 °C for 10 days was between 0.20 and 0.50 µm. In the tested pH conditions from 2.0 to 8.0, the MPD (d32) of emulsions stabilized by 2.0 wt % TPC-C was less than 0.20 µm. At Na+ concentration conditions between 0.10 and 0.50 mol/L, the MPD (d32) of emulsions was between 0.19 and 0.20 µm, and the zeta potential values varied from -34.10 to -32.60 mV. However, with an increasing Ca2+ concentration from 0.01 to 0.05 mol/L, the MPD (d32) of emulsions was between 0.20 and 21.65 µm, and the zeta potential raised sharply from -34.10 to -28.46 mV. The emulsions stabilized by TPC-C have a decent storage stability after a high-temperature heat treatment. Overall, tea polysaccharide conjugates strongly stabilized the emulsions, which support their new application as natural emulsifiers.

[Study on the preparation of effervescent tablets of EGb and its quality].

OBJECTIVE: To prepare effervescent tablets of EGb and establish quality preparation. METHOD: Taking pH, disintegration time and rigidity as index, the formulation and technique of EGb effervescent tablets were optimized by orthogonal experiment, the products were prepared and its stability were tested. RESULT: The optimum procedure condition was adding 12.5% citric acid, 20% sodium bicarbonate encapsulated by PEG6000, the products were tested by stability, the preparation was stable. CONCLUSION: It is valuable to be further studied as a new preparation of EGb.