| Gouqi (Lycium barbarum) is a major specialty resources in Northwest of China and a source of wide range of high nutritional value variety. The dry fruit of Jingning Gouqi of Gansu province was ued as the main material in this paper, with species of extraction reagent, ratio of extraction solvent, extraction temperature, extraction time, extraction frequency and Liquid ratio in the single factor test and orthogonal test (L934). The result indicated that using acet one and petroleum ether solvent with the volume ratio 1 to 5, at 50℃, let the ratio of the solid and the liquid be 1 to 3, picing up 3 times and every time was 60 minute as the optimum extraction condition of Gouqi pigments. The extraction temperature of Gouqi pigments reached a very significant level and the extraction times also reached a significant level under the orthogonal test (L934) of the 6 factors. Pigment powder of Gouqi was required under the saponification experiment of the solution of pigmnet of Gouqi with potassium hydroxide of the Concentration of 20 percent. The yield was 9.67 percent under the optimum of Gouqi pigments. Its coloration was well for the measured color of 36.7. The standard curve equation ofβ-carotene standard was Y=0.8457x-0.0208(R2=0.9989). According to the standard curve equation ofβ-carotene, the total carotene content of pigmnet of Gouqi was 168mg in 100g, and theβ-carotene content was 142.8mg in 100g.The stability of pigmnet of Gouqi in temperature, illumination, oxidants of aquae hydrogenii dioxidi, aid of citric acid, metal ions of kalium, natriumsodium, iron, copper and zinc and food addiitive was studied by colorimetry. The result indicated that temperature and illumination was the main factor for the stability of pigmnet of Gouqi, so it was conserved below 60℃and in dark condition. The oxidants of aquae hydrogenii dioxidi, aid of citric acid, most metal ions and most food additives had no effects for the stability of pigmnet of Gouqi except copper ions and sodium benzoate.The separation and purification of Gouqi pigments were measured through MgO, silica gel chromatography and TLC, and the changes of composition and contents of Gouqi pigments before and after saponification were measured with HPLC.The result indicated that the purification products were required by the elution of acetone and petroleum ether solvent with the volume ratio 1 to 15. Through the measuration of HPLC, the compositions of Gouqi pigments before chromatography was aliphatic ester of carotenoid, and the aliphatic ester of carotenoid was disassemble after saponification, its main composition wereβ-carotene, zeaxanthin and lutein, the content in turn wereβ-carotene, zeaxanthin and lutein. The content ofβ-carotene was reduced after saponification. Soβ-carotene was the main composition of Gouqi pigments.The pigment of Gouqi was extracted by acetone and petroleum ether solvent with the volume ratio 1 to 5. Its antioxidant activity was assessed by the reducing power of the pigment of Gouqi before and after saponification, the capacity of scavenging free radical for DPPH·, O2-,·OH, the antioxidant activity for lipid, the synergy with Vc, comparing with VE and Vc usually used as the traditional antioxidants. The results showed that the pigment of Gouqi existed a certain degree of reducing power and could scavenge DPPH·,·OH and O2- free radical effectively, and it could inhibit lipid oxidation and the antioxidant activity went up along with increasing concentration gradually. The antioxidant activities in turn were Vc, pigment of Gouqi before saponification, Vc and pigment of Gouqi after saponification, VE, pigment of Gouqi after saponification.
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