Study On Antioxidant And Stability Properties Of Red Raspberry Anthocyanin

Although widely distributed and abundant in China,raspberries have not been well industrialized and possess little acceptance by the public.That is mainly due to difficulties in transportation,processing and sales.Rich in anthocyanins,which is a good natural coloring agent and antioxidant,raspberries possess great potential for development in food and medicine.In this paper,the following studies were carried out:1.Optimizing the extraction process of anthocyanins from red raspberry and qualitative analysis of its components;2.Demonstrating the antioxidant properties of RRE in vitro and at the cellular level;3.In order to improve the application value and commercial value of red raspberry,red raspberry anthocyanins microspheres were successfully designed.The main research results were as follows:The single-factor experiment of ethanol concentration,extraction temperature,extraction time and solid-liquid ratio of RRE extraction process was optimized by response surface design.The response surface equation indicated that when ethanol concentration was 56.70%,the extraction temperature was 66.63%,extraction time was140.06 min,extraction ratio of the material and the anthocyanin was 1:18.89,the extraction efficiency of anthocyanin from red raspberry could be maximized.Under the optimal conditions,the relative error between the actual value and the predicted value was 4.02%.The actual anthocyanin content was 27.45 mg/100 g,which was better than Henan Xinyang Red Raspberry?16.2 mg/100 g?.HPLC-MS was employed for the qualitative analysis for extractive of red raspberry anthocyanins.Three anthocyanins were identified,which were cyanidin-3-glucoside,cyanidin-3-glucoside-5-glucoside and cyanidin,respectively.Remarkably,cyanidin-3-glucoside was the highest content anthocyanin of red raspberry,accounting for 47.20%of the total peak area.In vitro,compared with Vc and Trolox,five tests were carried out for evaluating antioxidant capacity of RRE.RRE exhibited superior antioxidant capacity.Using IC₅₀as an indicator,the order of self-extracting anthocyanins on these four free radical scavenging abilities was DPPH>ABTS>O₂^-·>·OH,which had good in vitro antioxidant capacity.At the cellular level,a model of oxidative stress induced by H₂O₂ in lung cancer A-549 cells was successfully constructed.H₂O₂ could decrease the activity of A-549cells,increase the content of reactive oxygen species,and break and fix nucleus.After RRE pretreatment,the intracellular ROS content was reduced,the degree of damage of the nucleus was improved,and the cell activity was improved.RRE was a good candidate for improving H₂O₂-induced oxidative stress damage and exhibited excellent antioxidant activity at the cellular level.In order to improve the stability of RRE,microspheres were successfully manufactured.The single-factor experiment of sodium alginate concentration,calcium chloride concentration and core wall ratio of microspheres preparation was optimized by response surface design.The response surface equation indicated when sodium alginate concentration was 4.43%,calcium chloride concentration was 1.86%,core-wall ratio was 1:3,the encapsulation rate could be maximized.Under the optimal conditions,the relative error between the actual value and the predicted value was 1.79%.Infrared spectroscopy and scanning electron microscopy of red raspberry anthocyanin microspheres showed that red raspberry anthocyanins were successfully encapsulated.The effects of different light and temperature conditions on the stability of red raspberry anthocyanins and red raspberry anthocyanin microspheres were investigated.The result showed that the red raspberry anthocyanin microspheres were more stable than red raspberry anthocyanins.