4种柠檬不同组织的酚类物质分布及其抗氧化特性

Distribution of Phenolics in Different Tissues of Four Kinds of Lemon and Their Antioxidant Activity

采用分光光度计法评价4种柠檬(尤力克黄柠檬、小青柠、青柠檬、香水柠檬)中果皮与果肉的总酚含量与抗氧化活性(清除ABTS+自由基能力、铁离子还原能力和清除DPPH自由基能力),并用超高效液相色谱对其酚类物质进行定性和定量。结果表明:4种柠檬果皮中的总酚含量及抗氧化活性均显著高于果肉(P<0.05),其中尤力克果皮与果肉的总酚、抗氧化活性均显著高于其余3个品种(P<0.05),而香水柠檬果皮与果肉中总酚、清除ABTS+自由基能力均最低。不同品种柠檬中酚酸、类黄酮种类及含量差异较大。从4种柠檬中共检出21种酚类物质,其中酚酸6种,黄酮6种,黄烷酮6种,多甲氧基黄酮3种。柠檬中的酚类物质主要是黄烷酮,占类黄酮总量61.82%～91.61%,其中青柠檬果皮中酚酸总量最高(535.62 mg/100 g DW),尤力克果皮中类黄酮总量最高(1 506.33 mg/100 g DW),果肉规律与果皮基本一致,然而其含量显著低于果皮含量(P<0.05)。从尤力克果皮与果肉中共检出15种酚类物质,其中圣草枸橼含量最高,而新绿原酸是含量最高的酚酸。从小青柠、青柠檬和香水柠檬的果皮与果肉中分别检测出19,16,15种酚类物质,其中橙皮苷含量均最高,而香草酸是含量最高的酚酸。不同品种柠檬的总酚和总类黄酮含量与ABTS+呈极显著的正相关性,同时总酚含量与DPPH呈显著性的正相关性。

In this paper, the content of total phenolic and antioxidant activity(ABTS+free radical scavenging ability, iron ion reducing ability and scavenging DPPH free radical ability) of peel and pulp of 4 kinds of lemon(Eureka Lemon, small lime, green lemon and ‘xiangshui’ lemon) were evaluated by spectrophotometer, and their phenolic compounds were qualitatively and quantitatively analyzed by ultra performance liquid chromatography. The results showed that: the total phenolic content and antioxidant activity of 4 kinds of lemon peel were significantly higher than those of pulp(P<0.05), and the total phenolics and antioxidant activity of Eureka Lemon peel and pulp were significantly higher than other three cultivars(P<0.05), and the total phenolics and ABTS+free radical scavenging capacity of the ‘xiangshui’ lemon peel and pulp were the lowest. There were significant differences in phenolic acids and flavonoids among different lemons, Among the 4 lemons, 21 phenolic compounds were detected, including 6 phenolic acids, 6 flavonoids,6 flavanones, 3 polyoxymethyl flavonoids. The main phenolic compounds in lemon were flavanones, accounting for 61.82-91.61% of total flavonoids, and the total content of phenolic acids in the green lemon peel was the highest(535.62 mg/100 g DW), the content of flavonoids in the Eureka peel was the highest(1 506.33 mg/100 g DW). The regular of the content in the pulp was similar to the peel, but the pulp was significantly lower than the peel(P<0.05). There were 15 phenolic compounds in Eureka peel and pulp, the highest content was eriocitrin, and the neochlorogenic acid was the highest content of phenolic acid. Small lime, green lemon and ‘xiangshui’ lemon peel and pulp were detected in 19,16,15 kinds of phenolic compounds, and the content of hesperidin was the highest among these varieties, and vanillic acid was the highest content of phenolic acid. The content of total phenolics and total flavonoids in different varieties of lemon had a highly significant positive correlation with ABTS+, and the total phenolic content had a significant positive correlation with DPPH.