Study On Synthesis And Oxidation Stability Of Conjugated Linoleic Acid Phytosterol Ester

Conjugated linoleic acid phytosterol ester is a kind of product, of which solubility is betterthan phytosterol, and oxidation stability is stronger than conjugated linoleic acid. At lowerdoses, it can have higher bioavailability, both the effect of phytosterol and conjugated linoleicacid-reducing serum cholesterol levels, anti-cancer, antioxidant effect. The preparation ofconjugated linoleic acid, synthesis process of Conjugated linoleic acid phytosterol esters and itspurification conditions, as well as oxidation resistance of sterol ester in peanut oil and lard weremainly studied in this thesis.With pumpkin seeds riched in linoleic acid as raw material in the text, linoleic acid wasseparated and purified by urea clathration. Using single factor experiment and orthogonalexperiment design method, to study various factors on the the effect of inclusion and separation.The results show that: proportion of fatty acid and urea was l:2.5, proportion of urea and ethanolwas l:3, clathration time was18h, clathration temperature was-15℃, with this understanding,most of the saturated fatty acid and oleic acid were separated, the percentage of linoleic acidincreased from43.13%to92.87%.Conjugated linoleic acid was preparation with KOH as catalyst, and examining the impact ofthe adding amount of alkali and glycerol, reaction time and temperature on the transformationeffect during the process. The results show that: proportion of KOH and linoleic acid was7:10,proportion of linoleic acid and glycerol was1:4, reaction time was40h and temperature was110℃, with this understanding,conjugated linoleic acid conversion rate can reach more than80%.Using stepwise esterification of phytosterols with conjugated linoleic acid catalyzed byNovozym435lipase in solvent-free medium, in combination with single factor experiment andresponse surface method optimization design, Optimal conditions of synthesis of conjugatedlinoleic acid phytosterol ester were as follows: reaction temperature55℃, addition of enzyme6%, reaction time45h, the degree of esterification can reach70%.Thin layer chromatography(TLC) was used for qualitative analysis, components of sterolester mixture were separated and purified by silica gel column chromatography. Highperformance liquid chromatograph and fourier transform infrared spectrometer analysis ofproducts after separation show that,with petroleum ether/ethyl ether/acetate (80:20:1, V/V/V) asdeveloping solvent, when the mobile phase flow rate of1.5mL/min, filling height of65cm, loading quantity of sample5g, components in the sample have good separation effect.Through investigate the solubility and peroxide value of sterol ester and phytosterols in oiland grease, indicated that solubility of the conjugated linoleic acid phytosterol ester in thevegetable oil improved20~30times than that of the phytosterols, and antioxidant effect of sterolester was better than that of phytosterols, when addition concentration of sterol ester was0.10mg/g, oxidation stability of peanut oil and lard oil was improved significantly. Lowconcentration of VEcan improve the antioxidant effect of sterol ester, addition of FeCl3reducedthe antioxidant effect of sterol ester, VCdid not have synergy on the oxidation stability of the VEand sterol ester.