摘要：在乌龙茶加工过程中,多糖含量以及组成多糖的中性糖、蛋白质含量呈递减趋势,从鲜叶至第2次摇青结束,下降幅度小,但第3次摇青后大幅度下降,而糖醛酸的变化较小;加工过程多糖清除·OH和 自由基的趋势基本一致,呈现抛物线变化,活性最高峰出现在第2次摇青结束,多酚类保留量为85%左右可以作为制定乌龙茶加工过程高活性茶多糖的形成指标。采用纤维素和葡聚糖凝胶柱层析法分离纯化乌龙茶多糖,各级分中性糖、蛋白质、糖醛酸含量以及清除OH、 的作用有较大差异。获得的乌龙茶多糖主要组分OTPS2-1是富含糖醛酸和少量蛋白质的三元糖复合物,相对重均分子质量为8.877×10⁴,糖基由半乳糖、葡萄糖、阿拉伯糖、岩藻糖和鼠李糖组成,其摩尔比为7.58:2.14:7.05:1.76:1.02。

During the process of Oolong tea, the extraction rate of TPS and the contents of its neutral sugar and protein decreased, particularly notably after the third shaking, but the content change of uronic acid was less. It was also indicated that the inhibiting effects of polysaccharide on radicals increased before the third shaking, and then decreased on Zuoqing stage. According to the changes of polyphenol content, when it was retained 85%, the content of TPS was highest and the effect on scavenging •OH and was best, which was regarded the technical index to end shaking during the process of Oolong tea. Four fractions of OTPS was obtained by DEAE-52 column chromatography, and there were obvious differences not only in contents of neutral sugar, uronic acid and protein of OTPS, but also in inhibiting effects on hydroxyl radical (•OH) and superoxide anion radical ( ). OTPS 2-1, a main fraction of OTPS, was obtained by DEAE-52 and Sephadex column chromatography. It was found that OTPS2-1 was a trinal compound of polysaccharide containing rich uronic acid and less protein. The results also showed that the molecular average-weight of OTPS2-1 was 8.877?10⁴, and it was composed of Gal, Glu, Ara, Fuc and Rha with a molar ratio of 7.58:2.14:7.05:1.76:1.02.