Studies On Preparation And Bioactivities Of Phytosterol Ester

Phytosterol was used as a novel functional food ingredient with plasma cholesterol lowering activities for years. In order to improve solubility of free phytosterols in edible fats/oils, preparation technology, bioactivities and applications of phytosterols ester were studied systematically in this dissertation. It included four parts:1) GC method for the quantitative of phytosterols was developed: HP-5 capillary gas-chromatography column; FID detector; injector 300℃; oven temperature 285℃; squalane as internal standard.2) Four kinds of phytosterols esters involving phytosterols acetate(PSA)phytosterols oletate(PSO),phytosterols stearic(PSS)andβ-Sitostanol nicotinate(PSN) was synthesized by chemosynthesis. The recrystallization method and optimal synthetic conditions of four phytosterols esters were studied. GC, IR and MS were used to determine the configuration of phytosterols esters. The solubility of phytosterols ester and phytosterols in soy salad oil were studied as well .Compared the catalysis of three lipases as biocatalyst to phytosterol laurate in a solvent-free system for pilot study: the Novo435 lipase was selected as biocatalyst, the optimal reaction conditions were confirmed to be 40℃, mole ratio of substrates 1:1,enzyme ratio over total weight 15%, reaction time 24h, and the yield of esterification was 36.5% in hexane.3) On therapeutic effect: compared with the hyperlipidemic model group, phytosterol esters could significantly reduce the serum TC, LDL-C and AI, lower the liver weight , TC and TG. There were different active effects among three phytosterol esters, PSA and PSO had ideal treatment effects on hyperlipidemia in mice and better than PSS.4) To evaluate the effects of PSO on the immune function : compared with the S18O-bearing mice model group,PSO could enhance significantly the phagocytosing ratio and the phagocytosing index(P<0.05 or P<0.01),the effects of PSO were better than Cyclophosphamide ; PSO also could improve evidently delayed—type hypersensitivity(P<0.05 or P<0.01),but worse than Cyclophosphamide;PSO could increase formation of antibody in splenic cells of S180-bearing mice,but there is not remarkable different(P>0.05);PSO had little influence on the contents of serum hemolysin(P>0.05). The results show that PSO could improve immunologic function of mice.5) Investigated the fermentation yogurt production technology of phytosterols acetate. The zymogen was fermented by Streptococcus thermophilus and Lactobacillus bulgaricus to 1:1;inoculation dosage was 3%; the amout of sugar was 5%, the amout of phytosterols acetate was 0.65 (every 200ml yogurt ); the zymolysis time was 5hr in 43℃. It was best to be cold stored at 0~5℃after fermentation and using post-acidification 24 h.