Synthesis And Applications Of Acetylated Catechins With Different Substituting Degrees

Catechin is one of the main functional components in tea. A lot of researches on catechinmodification have undertaken at home and aboard in recent years to improve the catechinsapplication characteristics. The thesis conducted the basic research on catechin acetylationcomprehensively. Firstly, we optimized the synthesis condition of O-acylation catechin （PAE and AE,PATP and ATP） with different degrees of substitution. Secondly, we explored the solubility,antioxidant activity and ultraviolet absorption of acetylated catechins with different degrees ofsubstitution. Finally, we studied the application of acetylated catechins in edible oil. The mainresearch results were as follows:1.On the basis of single factor experiment, optimum condition for synthesis of acylatedcatechins was that:0.1840g EGCG or0.1760g TP react with0.2mL acetic anhydride for5h underroom temperature in the presence of pyridine as catalyst.2. With the degree of substitution（DS） increased, the lipid solubility of acetylated catechinsenhanced, the total antioxidant capacity and scavenging effect on O₂^-· reduced. The UV absorptionspectra of acetylated catechins exhibit hypochromism with a small blue shift.3. Modification of catechin by acetic anhydride improve the solubility of catechin in edibleoil.The anti-oxidative effect of acetylated catechins for edible oil was strengthened with the increaseof concentration in the range of0.05mg/g to0.4mg/g. TBHQ and BHT had synergetic effect onanti-oxidation of the edible oil with acetylated catechins.The anti-oxidative rate of acetylatedcatechins have significant differences under40℃, room temperature and cold storage temperature,have no significant differences in dark and natural light.4. The kind and amount of acetylated catechins degradation products in edible oil was less thanpartial acetylated catechins. AE, a representative of acylated catechin, was stable in saturated waterethyl acetate, absolute ethanol and95%ethanol, but AE can deacetylate gradually in methanol and50%ethanol. The degradation rate of AE was faster in37.5℃than at room temperature. AE canwholly deacetylate within one hour in CO₃^2-solution, but stable in HCO₃^-solution in four hours.