火龙果果皮总黄酮和多糖的提取工艺及抗氧化研究

考察提取时间、料液比、乙醇体积分数和提取温度对火龙果果皮总黄酮和多糖得率的影响. 并在单因素实验结果的基础上设计L₉(34)的正交实验，优化总黄酮和多糖的提取工艺. 此外，通过进行DPPH ·、ABTS自由基及·OH的清除实验，考察火龙果果皮提取物的抗氧化活性能力. 正交实验优化得出的提取时间3 h、料液比1 ∶ 30、乙醇体积分数70%、提取温度70 ℃为火龙果果皮总黄酮和多糖的最佳提取工艺. 该条件下提取到的火龙果果皮总黄酮和多糖的平均质量分数分别为7.87 mg/g和114.05 mg/g. 在373.44 μg/mL时，抗坏血酸对DPPH ·、ABTS自由基及·OH的最大清除率分别达到95.25%、99.57%、89.99%；而火龙果果皮提取物的最大清除率分别为88.64%、60.84%和61.77%，数据表明火龙果果皮提取物对自由基的清除率均达到对照品的2/3，证实火龙果果皮提取物具有良好的抗氧化活性能力，可作为天然抗氧化剂的提取原材料.

On the Extraction and Antioxidation of Total Flavonoids and Polysaccharides from Pitaya Peel (Hylocereus undatus 'Foo-Lon')

The effects of extraction time, ratio of solid to liquid, ethanol concentration and extraction temperature on the yield of total flavonoids and polysaccharides from pitaya peel were investigated. On the basis of the single-factor test results, an orthogonal experiment of L₉(34) was designed to optimize the extraction process of total flavonoids and polysaccharides. In addition, the antioxidant activity of pitaya peel extract was investigated with experiments with DPPH·, ABTS free radical and ·OH scavenging assay. The optimal extraction conditions of total flavonoids and polysaccharides from pitaya peel were as follows: extraction time 3 h, solid-liquid ratio 1 ∶ 30, ethanol mass fraction 70%, and extraction temperature 70 ℃. Under these conditions, the average contents of total flavonoids and polysaccharides in pitaya peel were 7.87 mg/g and 114.05 mg/g, respectively. The in vitro antioxidant study showed that in the concentration of 373.44 μg/mL, the scavenging effect on DPPH ·, ·OH and ABTS radical was significant, and the maximum scavenging rates of the ascorbic acid were 95.25%, 99.57% and 89.99% while those of the sample were 88.64%, 60.84% and 61.77%, respectively. In conclusion, pitaya peel extract has good antioxidant capacity.