摘要
【目的】优化锌螯合法提纯石莼多酚工艺,评价提纯前后样品的抗氧化活性。【方法】以石莼多酚锌螯合率为指标,单因素试验初步探讨锌盐种类、氯化锌质量浓度、石莼乙醇粗提物质量浓度、乙醇体积分数、反应时间、pH等6个因素对石莼多酚螯合锌的影响,并通过响应面法优化其关键工艺参数;以石莼多酚锌螯合物解离率为指标,确定解离剂EDTA质量浓度;比较分析提纯前后样品对ABTS+·、DPPH·、·OH的清除能力。【结果】以83%乙醇溶液为溶剂,配制质量浓度为6.8 mg·mL^−1的石莼乙醇粗提物样液,控制氯化锌质量浓度15.0 mg·mL^−1,pH 8.0为优化提纯条件;此外,控制螯合反应时间30 min,解离剂EDTA质量浓度20 mg·mL^−1,提纯后样品中的石莼多酚含量由粗提物的6.95%增至25.18%,纯度提高了2.62倍。石莼乙醇粗提物与提纯物均具有良好的体外抗氧化活性,对3种自由基的清除能力顺序为•OH>DPPH•>ABTS+•。相比粗提物,提纯物对ABTS+•、DPPH•、•OH的清除能力分别提高了5.12、8.35、11.70倍,且当质量浓度分别达到16、12、8 mg·mL^−1后,对应的清除能力与VC无显著性差异。【结论】经过工艺优化的锌螯合法可以显著提高石莼乙醇粗提物中的多酚含量及其体外抗氧化活性,为石莼多酚的深层次开发应用提供参考依据。
【Objective】Polyphenols in the ethanol-extract of Ulva lactuca were purified by zinc-chelation,and antioxidant activities of the materials obtained before and after the optimization were compared.【Methods】Using the polyphenol-Zn^2+chelation rate as an indicator,effects of 6 parameters including variety of zinc salt,ZnCl2 mass concentration,ethanol volume fraction,reaction time,solution pH,and mass concentration of ethanol-extract from U.lactuca on the chelation were studied by a single factor experiment.Then,the process was optimized with the parameters using a response surface method.Applying the polyphenol-Zn^2+dissociation rate as an index,the proper EDTA mass concentration was determined.The scavenging capacities of the materials on ABTS+•,DPPH•,and•OH before and after the optimization were compared for analysis.【Results】The optimized process employed 83%ethanol as the solvent,ethanol-extract mass concentration at 6.8 mg·mL^−1,ZnCl2 mass concentration at 15.0 mg·mL^−1,pH at 8.0,chelation reaction for 30 min,and EDTA mass concentration at 20 mg·mL^−1 to raise the polyphenols content from 6.95%to 25.18%,representing a 2.62-fold increase over the original.The in vitro test on the crude ethanol-extract,as well as its purified product,exhibited antioxidant activity with scavenging capacities on 3 radicals in the order of•OH>DPPH•>ABTS+•.The purified polyphenols showed the scavenging capacities on ABTS+•,to be 5.12-fold,DPPH•,8.35-fold,and·OH,11.70-fold higher than those of the original ethanol-extract.And,in comparison to VC,no significant differences were observed on the scavenging capacities of the purified extract on those radicals at the concentrations of 16,12,and 8 mg·mL^−1,respectively.【Conclusion】The optimized zinc-chelation method significantly increased the polyphenols concentration and antioxidant activity of the crude ethanol-extract from U.lactuca.The approach might be applicable for the development and application of polyphenols extracted from seaweeds in general.
作者
陈雨晴
吕峰
王金铭
CHEN Yu-qing;LÜFeng;WANG Jin-ming(College of Food Science,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350002,China)
出处
《福建农业学报》
CAS
CSCD
北大核心
2019年第12期1447-1456,共10页
Fujian Journal of Agricultural Sciences
基金
福建省自然科学基金项目（2018J01695）
福建农林大学科技创新专项基金（CXZX2017016）
关键词
锌螯合法
石莼多酚
响应面法
抗氧化活性
Zinc-chelation
Ulva lactuca polyphenols
response surface method
antioxidant activity
