Separation Of Quercus Variabilis BL. Acorn Shell Pigment And Physico-chemical Properties And Antioxidation

In order to explore the natural functional pigment from Quercus variabilis BL. acorn shells, to improve the economic benefits of comprehensive utilization of acorns, the extraction and purification technology of the pigment in the acorn shell was studied with ultrasonic extraction and macro-porous resin separation methods, and the main composition of the pigment was identified by qualitative tests, quantitative tests, ultraviolet and infrared spectrum analysis, the physic-chemical properties and anti-oxidation of the pigment were investigated. The results were as follows:1. The optimum conditions of the pigment are that the crude pigment were treated by D4020 resin, added sample with 5 mg/mL pigment solution under pH3 at 2BV/h flow rate, eluted with 70% ethanol at 2BV/h flow rate at 2BV volume, the color value of the purified pigment is the highest with increasing by 62.1%.2. The pigment was preliminarily identified to be polyphenols by gelatin, dilute acid, bromine liquid, iron trichloride and aluminium trichloride. The UV spectrum analysis showed that there are absorption peaks near 224 nm and 276 nm. IR spectrum revealed that the main absorption wave numbers of the pigment are 1720、1612、1517、1445、1368、1280、1215、1110 cm-1. The results of the spectrum analysis indicated that the pigments are phenolic compounds and the main structure is procyanidine. The content of the total polyphenols and condensed tannins in the pigment are 70.04% and 62.91%, respectively.3. The pigment is freely soluble in methanol, water and alkaline solution, soluble in acid solution and alcohol, very slightly soluble in acetone, scarcely soluble in ethyl acetate and benzene. The pigment is stable but easy to precipitate under the acidity condition and unstable under the alkaline condition(pH>11). And it is stable under light, stable in the range of 25-100℃ and unstable to oxidant, reducer and chelated with Fe3+、Cu2+、Al3+、Mg2+、Zn2+. It shows high stability to Ca2+、Na+、K+.4. The IC50 of the pigment to scavenge DPPH and superoxide anion radicals are 0.021 and 0.226mg/mL, respectively. The IC50 of Vc to scavenge DPPH and superoxide anion radicals are 0.028 and 0.192mg/mL, respectively. The reducing power of the pigment is higher than Vc. The results demonstrated that the pigment has high antioxidant activity.