银杏叶黄酮的抗氧化性及其稳定性研究

Antioxidant activity and stability of flavonoids from ginkgo leaves

通过紫外分光光度法探究了银杏叶黄酮的抗氧化性及稳定性,其中银杏叶黄酮的抗氧化性主要分析了银杏叶黄酮清除DPPH自由基的能力与强氧化剂H_2O_2对于银杏叶黄酮稳定性的影响。其中银杏叶黄酮的稳定性主要分析了光照、存储时间、温度、pH、还原物、金属、食品添加剂对银杏叶中黄酮类化合物稳定性的影响。实验证明,银杏叶黄酮在避光存储5 d后无明显变化,光照可破坏其结构。20℃存储12 h银杏黄酮无明显变化,高温会导致其变性。弱酸性条件下比较稳定,Na_2SO_3可破坏银杏叶黄酮的结构,当银杏叶黄酮遇到Fe^(2+)和Fe^(3+)会极不稳定,苯甲酸钠与蔗糖对银杏叶黄酮稳定性影响不大,而抗坏血酸和柠檬酸对黄酮有着双重作用。因此,银杏叶黄酮在生产与存储过程中应避免光照、温度过高、过酸过碱、接触Fe^(3+)以及过高浓度的抗坏血酸和柠檬酸。

In this paper,the antioxidant activity and stability of flavonoids in Ginkgo biloba leaves were studied by UV spectrophotometry.The antioxidant activity of flavonoids from Ginkgo biloba leaves mainly explored the ability of flavonoids to remove DPPH free radicals and the stability of flavonoids from Ginkgo biloba leaves.The stability of flavonoids in Ginkgo biloba leaves mainly explored the effects of light,storage time,temperature,pH,reducing substances,metals and food additives on the stability of flavonoids in Ginkgo biloba leaves.The experiment proved that the flavonoids of Ginkgo biloba leaves did not change significantly after 5 days of storage in dark,and the light could destroy its structure.There was no significant change in the flavonoids stored at 20℃for 12 h,and the temperature was too high,which would cause denaturation.It is stable under weakly acidic conditions,and the Na2SO3 has a destructive effect on flavonoids.In addition,when flavonoids of Ginkgo biloba leaves encounter Fe2+and Fe3+,it is extremely unstable,and sodium benzoate and sucrose have little effect on the stability of flavonoids in Ginkgo biloba leaves.Ascorbic acid and citric acid have a dual effect on flavonoids.Therefore,ginkgo flavonoids should avoid light,excessive temperature,peracid and peralkali,contact with Fe3+and excessive concentrations of ascorbic acid and citric acid during production and storage.