Study Of Pomegranate Anthocyanins Extraction And Purification Process And Their In Vitro Antioxidant Activity

Pomegranate is one of the main fruit resources in China, which has attractive color andunique pharmacological effect as well as high nutrition health care value, and anthocyaninscompounds is one of its main active ingredients. The study of the anthocyanins extraction andpurification process of pomegranate is of great significance for the high value utilization offood additives, medicine, health care products, cosmetics and other fields.This thesis selected edible(San baitian,Jing Pitian) and medicinal pomegranate (Suan)juices and ornamental pomegranate(P. granatum L. var. Nigra) peel as the research object,and the anthocyanins purification of juices, the anthocyanins extraction of pomegranate peelas well as their antioxidant properties were studied, which were divided into the followingthree parts.1. Compared static and dynamic adsorption performance of5macroporous resins (AB-8, X-5, D101,101A, NKA-9), The results showed that AB-8resin is the ideal resin ofanthocyanins purification.The optimal condition for purification（Resin column Φ2.5cm×30cm）at25℃was found, as that the sample juice pH is adjusted to2.5, the initialconcentration of anthocyanin is0.0579mg/mL～0.0832mg/mL, and the desorption agent is70%ethanol (pH2.0).. For dynamic adsorption, the best performance was observed at pH of2.5, liquid flow rate of1.5mL/min and desorption elution flow rate of2mL/min. Under thiscondition，anthocyanins mass concentration of Jing Pitian pomegranate juice increased from109.01mg/L to146.06mg/L and that of Suan pomegranate juice rised from74.57mg/L to101.25mg/L.2. Response Surface Method was employed to study ultrasonic-assisted extraction ofanthocyanins from the peel of P. granatum L. var. Nigra. The optimum condition for theextraction of anthocyanins was concluded as that the temperature is40℃, the ethanolconcentration is70%, the material-solvent ratio is1:25, the ultrasonic time is40min, andultrasonic power is90W. The maximum extraction yield of anthocyanins was up to182mg/kg, compared to the predicted content183mg/kg, which proved that the optimization resultis reliable. 3.The total phenolics, tannins, flavonoids, anthocyanins and Vc contents of the originaljuices of three varieties were determined, and DPPH and ABTS radical scavenging assays aswell as FRAP assay were employed to determine the in vitro antioxidant activities of SanBaitian juice(SBT), Jing Pitian juice(JPT)，Suan juice(SSL) and JPT macroporous resinpurification anthocyanin samples(JPTA), SSL macroporous resin purification anthocyaninsamples(SSLA)，and anthocyanins extract of P. granatum L. var. Nigra peel(MSLA). Theresult shows that:(1) The anthocyanins mass concentration of the purified sample by AB-8resin issignificantly increased, and the sample has better antioxidant capacity than the originalsamples.(2) The anthocyanin contents range of the original juices(SBT, JPT, SSL) is0.91mg/~109.01mg/L, total polyphenol contents range1.87g/L~2.42g/L, total flavonoids contentsrange81.1mg/~90.2mg/L, tannin contents range1.65g/L~1.82g/L, VC contents range0.08mg/mL~0.18mg/mL.(3) All of pomegranate samples has good antioxidant capacity, with FRAP range of351~682μmol/100g, DPPH radical scavenging rate range of25.6%～47.7%, ABTS radicalscavenging rate range of60.2%～86.6%. Among them the anthocyanins extract of P.granatum L. var. Nigra peel(MSLA) has the strongest antioxidant capacity, with FRAP of0.84, DPPH radical scavenging rate of47.7%, ABTS radical scavenging rate of86.6%...