Study On Extraction, Purification And Properties Of Pigment From Edible Rose

Rose is a kind of Rosaceae plants. It is generally used as raw material for theextraction of rose oil. The rose residue is rich in anthocyanins with high edible as well asmedical value. Therefore, it is a natural pigment resource to be reused. In this thesis,extraction, purification, stability, structure and antioxidant activity were systematicallystudied and results were as follows:1. On the basis of single factor experiment, optimum conditions for pigmentextraction obtained by orthogonal experimental design were: temperature70℃, extractiontime1h,10%aqueous solution of citric acid, liquid-solid ratio50, extracted twice couldobtain the rate of96.60%.2. Based on the pre-experiment, AB-8macroporous resin was chosen through thestatic adsorption and desorption experiment, and the optimal purification conditions were:the concentration of anthocyanins0.08mg/mL, pH2.0, the flow velocity1mL/min. Thebest desorption conditions were:80%ethanol aqueous with0.1%hydrochloric acid and itsflow velocity was1mL/min, elution volume was220mL. The desorption rate could reachto87.15%, the color value was55.2and its purification was14.27%. The yield of pigmentand extraction ratio of anthocyanins were2.16%and87.19%, respectively.3. The stability tests of pigments from rose showed that the pigment was sensitive tothe pH of the solution, as the pH value increased, the wavelength of maximum absorptionredshifted and the color changed from red to gray. Temperature, K+, Zn²⁺, Fe²⁺saccharidesand antiputrefactiva had no significant effects on the stability of anthocyanins; light, Mg²⁺,VC, H2O2and Na2SO3would decrease the stability of anthocyanins, while Cu²⁺、Al3+、Ca²⁺、Na+、could increase the stability of anthocyanins.4. From the analysis results of qualitative test, UV visible spectroscopy and highperformance liquid-mass spectrometry （LC-MS）, Cyanidin-3,5-diglu was the predominantconstituent which accounted for approximately94.9%of the total anthocyanins contentand Cyanidin-3-glu accounted for2.1%.5. The in vitro antioxidant activities of pigment from rose were simultaneouslystudied. The total phenol was666.5mg GAE/g. Extract from rose exhibited excellentreducing capacity and free radical scavenging activity against both DPPH and ABTS. ItsEC50values of DPPH, ABTS and ferric reducing ability were20.8μg/mL,18.3μg/mL,2.6μg/mL, respectively, while EC50of the equivalents （GA） were184.3μg/mL,33.0μg/mL and10.3μg/mL, which indicated that the antioxidant activity of rose extract wasbetter than GA.