Effect Of Copigment On Antioxidant Activity And Antioxidant Stability Of Jujube Pigment

Jujube pigment extracted from waste jujube dregs,such as juice and fruit wine,is a kind of natural pigment resource with natural color,rich content,safety and non toxicity.Studies have shown that jujube pigment has good antioxidant activity in vitro,which can protect the oxidative damage of vascular endothelial cells induced by H2O2,improve the oxidative stress-induced liver damage and KBrO3-induced renal damage in mice.However,the active components of jujube pigment,such as flavonoids,polyphenols,anthraquinones and m-diphenols,are easily affected by environmental factors due to their large amount of phenolic hydroxyl and change its stability.A large number of studies have confirmed that adding copigments is one of the most effective and common methods to maintain the stability of natural pigments.The common copigments include phenols,organic acids,alkaloids,flavonoids,amino acids,nucleotides,metals and other anthocyanins.The type and concentration of copigments are the important factors affecting the copigmention.Therefore,the subject takes jujube pigment as the research object to study the influence of copigments on the antioxidant activity,anti lipid peroxidation ability and antioxidant stability of jujube pigment by adding different copigments,so as to lay a theoretical foundation for the application of jujube pigment in food and the development of functional food.The experimental results are as follows:(1)Screen the copigments.Phenolic acids,flavonoids,amino acids and organic acids were selected as copigments.The copigments were selected according to the absorbance value of red jujube pigment and the increase of absorbance value I per mole of copigments.The results showed that adding 10 mmol/L tea polyphenol,tannic acid,ferulic acid and 0.2 mmol/L rutin,baicalein,naringin,quercetin and puerarin to jujube pigment could improve the stability of jujube pigment and could be used as copigments of jujube pigment.(2)To study the effect of copigments on antioxidant activity of jujube pigment in vitro.The scavenging system of DPPH�,ABTS+�,�OH,O2-�and the determination method of reducing power were established to evaluate the effect of copigments on the antioxidant activity of jujube pigment.The results showed that adding copigments could significantly improve the antioxidant activity of jujube pigment,and the ability of scavenging DPPH�,ABTS+�,�OH,O2-�and reducing power all were significantly higher than jujube pigment(p<0.05).The scavenging ability of ferulic acid,baicalein and puerarin to the free radicals of jujube pigment was slightly stronger than that of other copigments,while the scavenging ability of naringin to DPPH�,the scavenging ability of tea polyphenol,quercetin and naringin to ABTS+�were not significantly different from that of jujube pigment(p>0.05).The results showed that adding ferulic acid,puerarin,baicalein and other copigments to red jujube pigment could also improve the antioxidant activity of red jujube pigment.(3)To study the effect of copigments on anti lipid peroxidation of jujube pigment.Through the establishment of soybean oil lipid,Fe2+induced vitellin,linoleic acid lipid,Fe2+catalyzed linoleic acid,H2O2 induced hemolysis of red blood cells and red blood cell membrane,spontaneous mice,H2O2 induced,Fe2++H2O2 combined induced lipid peroxidation system of liver tissue and the determination of swelling degree of mitochondria,the inhibition of lipid peroxidation and swelling degree of mitochondria of liver cells by copigments were studied.The results showed that the copigments could significantly improve the anti lipid peroxidation of jujube pigment,tannic acid,rutin,scutellarin and puerarin could significantly inhibit soybean oil,linoleic acid,lecithin,hemolysis of mice red blood cells,anti lipid peroxidation of liver tissue system and swelling of mitochondria of mice liver cells(p<0.05).The copigmention treatment of jujube pigment with ferulic acid,quercetin and naringin could obviously inhibit the lipid peroxidation of vitellin system,and quercetin has a negative effect on the anti lipid peroxidation of jujube pigment.In the selection of application,tannic acid,rutin,baicalein and puerarin can be considered as copigments of jujube pigment.(4)To study the effect of copigments on antioxidant stability of jujube pigment.The effects of temperature,light and pH on the absorbance of jujube pigment juice solution,scavenging DPPH�ability and the inhibition of Fe2+induced lipid peroxidation of vitellin were studied.The results showed that the copigments can significantly enhance the stability and antioxidant stability of jujube pigment(p<0.05).In jujube juice system,jujube pigment has good stability under the environment of temperature(<60 ?),light(indoor or dark),pH(?7.0),is not easy to be affected by environmental factors,and maintains good antioxidant stability.Therefore,the stability and antioxidant stability of jujube pigment could be significantly improved by adding tannin,baicalein and rutin as copigments under the conditions of high temperature,sunlight and acid environment(p?0.05).