不同提取方法对茶多酚理化性质的影响

以绿茶为原料，研究茶多酚的超声波提取、酶法提取、常规浸提、热回流提取以及纤维素酶协同超声波提取法，比较评价所得茶多酚的理化性质。结果表明：90℃热回流提取得到的提取率、产品纯度最高，但是过高的热回流提取温度导致产物抗氧化活性低；超声波在室温条件下提取茶多酚能获得较高的提取率和较好的产品纯度，产物抗氧化活性相对最强；酶法和纤维素酶协同超声波法提取能够获得较高的提取率，但是产品纯度和抗氧化活性低于超声波法所得结果。

Effect of Extraction Methods on the Physico-chemical Properties of Green Tea Polyphenols

Green tea polyphenols (TPs) were extracted by hot water reflux extraction, combination of cellulase hydrolysis and ultrasound-assisted extraction or each of them and extraction with room temperature water, respectively, and the resultant products were measured for their physico-chemical properties. The results showed that the extraction efficiency and product purity resulting from hot water reflux extraction at 90 ℃ were higher than those resulting from other 4 methods, but the product obtained had lower hydroxyl free radical scavenging activity than that obtained at lower reflux temperatures. Ultrasoundassisted extraction at room temperature exhibited better extraction efficiency and product purity, and the hydroxyl free radical scavenging activity of the product obtained was higher than that of the products obtained by other 4 methods. Combination of ultrasound-assisted extraction and cellulase hydrolysis gave better extraction efficiency; however, the purity and hydroxyl free radical scavenging activity of the product obtained were both lower than those of the product obtain by ultrasound-assisted extraction alone.