不同类型桃果肉酚类物质及抗氧化活性分析

【目的】探讨不同类型桃果肉中酚类物质组成、含量及其抗氧化活性的差异,为桃的品质育种和科学利用提供参考。【方法】以水蜜桃、蟠桃和油桃3种类型共15个品种的桃果肉为试验材料,使用高效液相色谱法(high performance liquid chromatograph,HPLC)检测各品种中的酚类物质,采用1,1-二苯基-2-苦基苯肼自由基(1,1-diphenyl-2-picrylhydrazy,DPPH)、2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸(2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid diammonium salt,ABTS)自由基清除能力和铁离子还原能力(Ferric reducing/antioxidant power,FRAP)3种方法测定抗氧化能力,并利用相关性分析酚类物质与抗氧化活性的关系。【结果】供试品种总酚与总黄酮含量的变异范围分别为0.35—2.54 mg CHA·g-1 FW和0.08—3.32 mg RE·g-1 FW。整体上蟠桃总酚及总黄酮含量高于水蜜桃和油桃,‘早露蟠桃’的含量最高。3种类型桃果实中共检测到酚酸6种(没食子酸、香草酸、原儿茶酸、阿魏酸、新绿原酸、绿原酸)和类黄酮4种(儿茶素、表儿茶素、芦丁、槲皮素)。表儿茶素、儿茶素、绿原酸和新绿原酸在桃果实中的含量最为丰富,不同类型桃果实的酚类物质组成与含量明显不同。其中,水蜜桃以表儿茶素和绿原酸为主,变异范围为37.57—105.49μg·g-1和40.19—49.8μg·g-1;蟠桃以表儿茶素、绿原酸、新绿原酸和儿茶素为主,变异范围分别为35.94—297.32μg·g-1、36.14—80.57μg·g-1、1.45—29.26μg·g-1和0—44.64μg·g-1;油桃以绿原酸和儿茶素为主,变异范围为30.97—48.05μg·g-1和9.22—53.73μg·g-1。DPPH清除速率、ABTS和FRAP值分别为0.21—7.01μmol TE·g-1 FW、0.66—8.57μmol TE·g-1 FW和0.59—5.60μmol TE·g-1 FW,综合抗氧化指数依次为:蟠桃水蜜桃油桃。供试品种中,‘早露蟠桃’多酚含量与抗氧化能力最高。总酚、总黄酮、新绿原酸、表儿茶素与DPPH清除速率、FRAP及ABTS均呈极显著的正相关关系(P0.01)。【结论】不同类型桃果实中酚类物质及抗氧化能力差异较大,表儿茶素和绿原酸是水蜜桃的主要酚类物质,表儿茶素、儿茶素、绿原酸和新绿原酸是蟠桃的主要酚类物质,绿原酸、儿茶素是油桃的主要酚类物质。蟠桃的酚类物质含量和抗氧化能力均高于水蜜桃和油桃,表儿茶素和绿原酸在桃果实抗氧化能力中起着重要的作用。

Phenolic Profiles and Antioxidant Activity of Fruit Pulp from Different Types of Peaches

【Objective】 The aim of this study was to provide reference for the quality breeding and scientific utilization of peach by analyzing the difference of the content and composition of phenolic compounds and antioxidant activity of fruit pulp from different types of peaches.【Method】In this study, phenolic compounds of 15 peach cultivars, including five honey peach cultivars, flat peach cultivars and nectarine cultivars, were determined by high performance liquid chromatography (HPLC), and the antioxidant activities of their extracts were evaluated by DPPH, FRAP and ABTS⁺ antioxidant index. And the relationship between phenolic compounds and antioxidant activity were also analyzed by correlation analysis.【Result】The total phenolic content of 15 peach cultivars ranged from 0.35 to 2.54 mg chlorogenic acid equivalent (CHA)·g^-1 fresh weight (FW), total flavonoid ranged from 0.08 to 3.32 mg of rutin equivalent (RE)·g^-1 FW. On the whole, the total phenolic and total flavonoid contents in flat peach were significantly higher than those in honey peach and nectarine, Zaolupantao had the highest content of total phenolic and total flavonoid. A total of 6 phenolic acids (gallic acid, vanillic acid, protocatechuic acid, ferulic acid, neochlorogenic acid and chlorogenic acid) and 4 flavonoids (catechin, epicatechin, rutin, and quercetin) were identified from the tested peaches. Epicatechin, catechin, chlorogenic acid and neochlorogenic acid were the most abundant phenolic compounds in peach fruits. The composition and content of phenolics in three types of peaches were different. Epicatechin and chlorogenic acid were rich in honey peach cultivars, varying from 37.57 to 105.49 and 40.19 to 49.8 µg·g^-1 FW. Epicatechin, chlorogenic acid, neochlorogenic acid and catechin were rich in flat peach cultivars, ranging from 35.94 to 297.32, 36.14 to 80.57, 1.45 to 29.26 and 0 to 44.64 µg·g^-1 FW, respectively. Chlorogenic acid and catechin were rich in nectarine, ranging from 30.97 to 48.05 and 9.22 to 53.73 µg·g^-1 FW, respectively. The value of DPPH inhibition, ABTS and FRAP in tested fruits were 0.21-7.01, 0.66-8.57 and 0.59-5.60 µmol trolox equivalents (TE)·g^-1 FW, respectively. The overall antioxidant potency composite index (APCI) revealed that flat peach presented the highest antioxidant capacity, followed by honey peach and nectarine. Among these tested cultivars, Zaolupantao not only contained the highest phenolic content, but also presented the highest antioxidant activity. There was a significantly positive correlation between total phenolic, total flavonoid, neochlorogenic acid, epicatechin and DPPH inhibition, ABTS, FRAP values (P<0.01).【Conclusion】 These results indicated that there are significant differences in phenolics and antioxidant capacity in different types of peaches. Epicatechin and chlorogenic acid are the main phenolic compounds of honey peach, epicatechin, catechin, chlorogenic acid, neochlorogenic acid are the main phenolic compounds of flat peach, chlorogenic acid and catechin are the main phenolic compounds of nectarine. Overall, flat peach presented higher phenolic content and antioxidant capacity than honey peach and nectarine. Epicatechin and chlorogenic acid may play an important role in antioxidant capacity of peach fruit.