Extraction Purification And Characterization Of Flavonoids From Aronia Melanocarpa

Aronia melanocarpa is a kind of small berry with high medicinal value,nutritional value and health care effect,and has been listed as a new food raw material in recent years.It also has multiple biological activities such as antioxidant,antibacterial,anti-cancer and blood sugar reduction,which has good development prospects and scientific research value in food,cosmetics,medicine and other fields.As natural antioxidants,flavonoids have good antioxidant activity,which can remove the free radicals accumulated in the human body and achieve the purpose of protecting the body.The extraction and purification process of flavonoids from Aronia melanocarpa were studied in this paper,and the stability and antioxidant activity in vitro were analyzed,aiming to provide some experimental basis for the development of flavonoids and related products.The main research contents and conclusions are as follows:(1)The effects of ethanol concentration,liquid-solid ratio,extraction time and extraction temperature on the amount of flavonoids extracted by microwave assisted extraction were investigated.Using Box-Behnken experimental design and response surface analysis method,the best extraction process was obtained.The optimum extraction technology was as follows:ethanol concentration of 59%,liquid-solid ratio of 25:1 m L/g,extraction time of 25.5 min,and extraction temperature of 60.6?.Under this process conditions,the amount of flavonoids was up to 7.929 mg/g.(2)The crude extract of Aronia melanocarpa was purified by large hole resin,and AB-8,HPD400,NKA-9,X-5,D101 were screened with static adsorption rate and desorption rate as the evaluation index.The results showed that the adsorption rate and desorption rate of D101 resin were the best among the five resins,and the adsorption rate was 60.55%and desorption rate was 62.48%.Therefore,D101 macroporous resin was selected to purify the crude extract of flavonoids from Aronia melanocarpa.By single factor test,the optimum technological condition was obtained as follows:loading p H of 5,loading concentration of 16 mg/m L,elution p H of 5 and elution ethanol concentration of70%.The content of flavonoids was 129.44 mg/g after purification,which was significantly higher than that before purification(16.83 mg/g).The DPPH free radical scavenging rate of flavonoids after purification was also significantly higher than that before purification.(3)The influences of p H,temperature and metal ions on the stability of flavonoids from Aronia melanocarpa were studied with the content of flavonoids as index.The results showed that the flavonoids from Aronia melanocarpa were stable at p H 5 and suitable for preservation at 4?.K⁺,Na⁺,Mg²⁺and Ca²⁺had little effect on the flavonoids content,while Fe³⁺had obvious influence on its content.Therefore,Fe³⁺should not be exposed to the flavonoids in the preservation process.(4)DPPH and ABTS free radical scavenging rates of flavonoids in Aronia melanocarpa were used as indexes,and ascorbic acid was used as a positive control.The effects of three drying methods including hot blast drying,vacuum drying and freeze drying on the antioxidant activity of flavonoids in vitro were investigated.The results showed that the flavonoids had good antioxidant activity,and the free radical scavenging ability increased with the increase of flavonoids concentration.The antioxidant capacity of three drying methods and ascorbic acid to flavonoids in vitro was as follows:ascorbic acid>freeze drying>vacuum drying>blast drying.