白肉番石榴总黄酮提取工艺优化及体外抗氧化活性分析

对白肉番石榴中总黄酮的提取工艺进行优化,并研究其体外的抗氧化活性。以珍珠番石榴(白肉)的叶、皮为原料,在单因素实验的基础上,以总黄酮提取量为指标,采用正交试验优化获得了番石榴叶、皮中总黄酮的提取工艺。在此基础上提取番石榴果肉中的总黄酮,然后比较番石榴叶、皮、果肉中黄酮的体外抗氧化作用。结果表明,番石榴叶、皮的总黄酮的最优提取工艺略有差异。番石榴叶总黄酮的提取最优工艺为:乙醇浓度50%,提取温度65 ℃,料液比1:20 (g/mL),提取时间135 min。番石榴皮总黄酮提取最优工艺为:乙醇浓度60%,提取温度45 ℃,料液比1:7 (g/mL),提取时间105 min。在最优条件下番石榴叶、皮总黄酮的提取量分别为(188.66±0.23)、(48.03±0.16) mg/g。番石榴叶、皮、果肉总黄酮在ABTS自由基及羟基自由基清除实验、铁还原力及总抗氧化力测定分析中显示良好的抗氧化活性,其中番石榴叶总黄酮的体外抗氧化能力最强。由此说明番石榴黄酮有望成为一种良好的天然抗氧化剂。

Optimization of Extraction Process and in Vitro Antioxidant Activity Analysis of Total Flavonoids from White-flesh Guava(Psidium guajava L. cv. Pearl)

The extraction process of total flavonoids from white-flesh guava was optimized and the in vitro antioxidant activity was studied. The leaves and peel of pearl guava(white meat)were used as raw materials. Based on a single factor experiment,the total flavonoids extraction quantity was used as an indicator to optimize the extraction process of total flavonoids from leaves and peel of guava by orthogonal test. On this basis,the total flavonoids in flesh of guava were extracted,and the in vitro antioxidant effects of total flavonoids in leaves,peel and flesh of guava were compared. The results showed that the optimal extraction process of total flavonoids from leaves and peel of guava were slightly different. The optimal extraction process of total flavonoids from guava leaves were as follows:ethanol concentration 50%,extraction temperature 65 ℃,solid-liquid ratio 1:20 (g/mL),extraction time 135 min. The optimum extraction process of total flavonoids from guava peel were as follows:ethanol concentration 60%,extraction temperature 45 ℃,solid-liquid ratio 1:7 (g/mL),extraction time 105 min. Under optimal conditions,the extraction quantities of total flavonoids in guava leaves and peel were(188.66±0.23)and(48.03±0.16) mg/g,respectively. Total flavonoids of guava leaves,peel and flesh showed good antioxidant activity in the experiments of ABTS radical and hydroxyl radical scavenging experiments,iron reducing force and total antioxidant capacity,among which total flavonoids of guava leaves had the strongest antioxidant capacity in vitro. This indicated that white-flesh guava flavonoids were expected to be a good natural antioxidant.