The Extraction And Antioxidation Protection Of The Betacyanin From The Pitaya Peel

Consumption of natural pigments has the advantage of being more nutritious and safer,and has become a hot topic in the field of food additives at home and abroad.In the process of scientific research staff constantly exploring the best natural pigments,it is found that the poor stability of edible natural pigments is a bottleneck problem of its development.At present,the peels producted in the production and processing process of Pitaya are rich in natural pigment-betanin,but there are few study reports on the high-purity purification process and stability.Therefore,in this paper,the betanin was separated and purified from the common white meat pitaya peel as raw material.The degradation kinetics model was established,and the antioxidant activity was evaluated.It provided the experimental evidence for the development of new functional natural pigments.The specific research contents and results were as follows:The pitaya peel was used as raw material,and the crude extract of betanin was extracted by distilled water.The optimum extraction conditions were as follows:the ratio of material to liquid was 1:5?m/V?,the extraction pH was 5.0,and unter 40°C water temperature bath extraction was 1.4h.The highest extraction rate of crude betanin was obtained to16.83%±0.2905%.Purification of betanin from the crude extract using AB-8 macroporous resin purification method revealed that the pH was 4.0,the adsorption time was 1h,the sample concentration was 2 mg/mL,the flow rate was 1 mL/min,and 30%ethanol was used for 1 h.The color value of purified betanin was 11.53±0.603,which was 5.5 times higher than that of the crude extract.The purity was 91.23%as identified by high-phase liquid chromatography.Taking the preservation rate?%?of betanin as an indicator,the effects of 7 metal ions and10 common food additives?carbohydrates,acid additives?on their stability under different conditions were investigated.The results showed that Fe³⁺,Al³⁺,and Cu²⁺ions had a destructive effect on the betanin of pitaya peel,and Na⁺,K⁺,Mg²⁺,and carbohydrates could play a role in auxiliary coloration.When lactose concentration was 10%and storage time was within 120 h,the highest preservation rate of betanin was 88.4%.0.2⁰.3%citric acid has the effect of improving the stability of betanin.To study the degradation kinetics of betanin of pitaya peel in aqueous solution,lactose solution and potassium chloride solution under different temperature,pH and light conditions.The results showed that the degradation reactions of three kinds of betanin solutions in different temperature,pH and light conditions belonged to the first-order reaction.10%lactose solution at high temperature?above 40°C?,pH 2.0⁸.0,light and dark than the aqueous solution conducive to the preservation of pitaya peel betanin.The aqueous solution of0.08mol/L potassium chloride in the acid and neutral conditions at high temperature was more conducive to the preservation of betanin in pitaya peel.Under the acidity and neutrality conditions at high temperature,the aqueous solution of 0.08mol/L was better than the aqueous solution for the preservation of betanin in pitaya peel.The DPPH radical scavenging rate,·radical scavenging rate,and O·radicalscavenging rate were intected as indicators for evaluation by external spectrophotometry.The abilities of eliminating DPPH,·and eliminating·were positively correlated with the concentration of betacyanin.In contrast to the one of Vc,the antioxidant activity of betanin in vitro was analyzed.The results showed that its antioxidant capacity was slightly lower than Vc.The H₂O₂-induced oxidative damage model of human umbilical vein endothelial cells?HUVECs?was constructed and the ability of betanin repair cells to oxidative damage was detected by MTT assay.As a result,betanin significantly reduced H₂O₂ induced oxidative damage to HUVECs and inhibited cell death in a dose-dependent manner.Flow cytometry was used to detect the apoptosis rate of the cells.It was found that betanin could dose-dependently antagonize H₂O₂-induced apoptosis of HUVECs in a concentration range of0.2-0.4 mg/mL.