Preparation, Antioxidant Activity And Stability Of Lycopene And β-carotene From Papaya

There are abundant nutritive value and important biological function in papaya,which always enjoyed the reputation of "the king of fruits in ling nan area".There are many kinds of carotenoids in flesh,especially higher contents of lycopene andβ-carotene,and their important physiological function.The paper is aimed at the research on these two fat-soluble carotenoids.(1) Use solvent extraction to figure out the optimal extraction technics of carotenoid from papaya combined with One-way and Orthogonal design:use 95%ethanol as extractant,at the solid/liquid ratio of 1/13 (1/5,1/4,1/4 m / v),at 35℃,under 100 min,Extracting carotenoids from flesh pulp,Then extracting carotenoids from residue of the above papaya futher more using petroleum ether,the total content of carotenoids in papaya flesh was 73.3±8.0μg/g:(2) Establishment of the test condition of lycopene andβ-carotene in papaya:In TLC system with silica-gel solid phase,developer is petroleum ether/acetone/dichloromethane = 18/0.1/0.3～0.4.In coarse separation with silica-gel column chromatography,the eluent is petroleum ether/acetone = 100/0-5,gradient elution.In separation and purification,n-Hexane is used as eluent forβ-carotene sample,while for lycopene sample,optimized eluent is n-Hexane/acetone = 100/0.5.When HPLC is used to separate carotenoids from papaya,mobile phase is acetonitrile/Tetrahydrofuran/water = 69/28.5/2.5.(3) Use silica-gel column chromatography combined with TLC tracking to separation and purification, use spectrometry and chromatography,such as ultraviolet and visible spectrometry,thin-layer chromatography,high performance liquid chromatography,infrared spectrum and so on,to qualitative and quantitative.The results from shows that the separate and purity of lycopene andβ-carotene from column chromatography reaches above 90%.(4) Quantitative analysis of lycopene andβ-carotene from papaya by using HPLC standard curve,and the results are:lycopene 1145.5μg/100g,β-carotene124.05μg/100g.(5) Prove the antioxidant activity of carotenoids contracts,lycopene andβ-carotene from papaya through researching its effects on the oxidation induction time of lipid(lard and peanut oil);Through calculation preserving rate of carotenoids from papaya with different illumination and temperature,we conclude that at carotenoids extraction and separation,low temperature and light-shielding measures should be taken to reduce the damage to papaya carotenoids by light and high temperature.