凌云白毫茶多糖超声波提取工艺优化及其抗氧化效果

以凌云白毫为原料，优化茶多糖提取工艺，并探讨茶多糖的抗氧化效果。以茶多糖得率为响应值，在单因素实验的基础上采用Box-Bohnken法优化茶多糖超声波辅助热水浸提工艺。考察茶多糖对羟基自由基（·OH）、1,1-二苯基-2-三硝基苯肼自由基（DPPH·）的清除率及对油脂自氧化反应的抑制情况，评价其抗氧化效果。实验结果表明，茶多糖的最佳提取工艺为:液料比69:1 mL/g、提取温度52 ℃、超声时间21 min、超声功率180 W，实测茶多糖平均得率为（4.84%±0.04%），接近模型预测值5.06%（<5%）。抗氧化效果测试结果表明，茶多糖清除·OH、DPPH·的IC₅₀分别为0.262、0.438 mg/mL，且其抗氧化能力与浓度成正向关系。同时，茶多糖可抑制油脂的自氧化反应，延长油脂在常温常压环境中的保存时间。凌云白毫茶中茶多糖的含量较为丰富，且具有良好的抗氧化效果，可为凌云白毫在国内外的深度推广提供数据支撑。

Optimization of Ultrasonic Extraction of Polysaccharides in Lingyun Pekoe and Its Antioxidant Activity

Lingyun pekoe as starting material, studies were carried out to optimize the extracting technology of polysaccharides, and investigate its antioxidant activity. Extracting yield of polysaccharides as the index, the extraction conditions were optimized by Box-Bohnken method based on the results of single-factor experiments. The antioxidant activities were evaluated by the determination of hydroxyl radical (·OH), 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH·) , and inhibition effect on auto-oxidation of grease. Experimental results showed that, the optimal extraction conditions were obtained as follows: liquid-material ratio 69:1 mL/g, temperature 52 ℃, ultrasonic time 21 min, ultrasonic power 180 W. Under the optimal conditions, an average extraction yield (4.84%±0.04%) was obtained, which was similar with the expected yield 5.06% (<5%) of regressive equation. The IC₅₀ of polysaccharides for eliminating ·OH, DPPH· were 0.262, 0.438 mg/mL, and a better clearance result would be obtained with higher concentration. Moreover, polysaccharides could prolong the storage time of grease in normal circumstance for inhibiting the auto-oxidation. The studies mentioned above indicated that polysaccharides were plentiful in Lingyun poeke, and had a good antioxidant activity, providing data support for promoting in home and abroad.