Preparation And Research Of Tea Polyphenols W/O Microemulsion Using Edible Oil As Contineous Phase

Lipopholic property of tea polyphonels has restricted their application as natural antioxidant in oil.In order to increase the solubility of tea polyphenols(TPs)in edible oil,water in oil(W/O)microemulison(ME)using edible oils as continuous phase to envelop TPs was prepared.The ternary phase diagram,particle size,electrical conductivity,viscosity,rheological properties as well as the antioxidant capacity of the ME were investigated.This paper studied the soybean oil/Span80-Tween80/ethanol/water reverse ME system firstly.The results showed: the W/O ME formed when water content was below 30%.The mean particle size of the ME system was about 8.40 nm and kept basically stable within 45 days.The ME was characterized as newtonian viscous fluid at high shear rate,pseudoplastic at low shear rate.Moreover,the ME had nice salinity and pH tolerance.The peroxide value determination indicated that the antioxidant capacity of the ME was enhanced greatly by the addition of TPs.Secondly,linoleic acid/ethanol/water ME to envelop TPs was prepared,and in this system,the linoleic acid played a dual role of both oil phase and surfactant phase.Then the ternary phase diagram,particle size,electrical conductivity,rheological behavior and antioxidant capacity were investigated.The results showed the W/O ME was formed when linoleic acid content was above 24%.This ME had a uniform particle size and was also characterized as newtonian viscous fluid at high shear rate,pseudoplastic fluid at low shear rate.Result of antioxidant capacity experiment showed that compared with the empty ME,oxidation inhibition rate of ME with water phase adding 0.01 g/mL tea polyphenols was 68.32%,adding 0.1 g/mL tea polyphenols was 92.42%.Finally,based on the results of the first two system researches,we selected glyceryl monooleate(GMO)-Tween80 as composite surfactant and added a certain amount of linoleic acid to reduce the surfactant content.We use edible oil(soybean oil,corn oil,sunflower oil)as oil phase,tea polyphenols water-ethanol solution as water phase to prepare W/O ME.And researched its formulation,characterization and antioxidant capacity as well as the proper additive amount of tea polyphenols to microemulsion.This article focused on using food-grade surfactants to prepare tea polyphenols W/O ME and try to reduce the surfactant content.It explored the feasibility of using TPs as natural antioxidant in edible oil by method of W/O ME,provided certain reference for related research.