| In recent years, with the improvement of people's consciousness on environmental protection, "green chemistry" has obtained highly attention. For this reason "green surfactants" has gradually become a hot research in the field. Biocompatible surfactant which has the advantages of green, easy degradation and harmless to human shin is a kind of "green surfactants". So, we chose biocompatible surfactant to build the microemulsion and explored various factors' influence on the phase behaviors of microemulsion. And select the proper microemulsion systems used for entrapment tea polyphenols which is water-soluble natural antioxidant, to explore the influence on the oxidation resistance of vegetable oil. This exploration may provide a theoretical basis for the application of tea polyphenols in vegetable oil development. This paper mainly includes the four chapters as follows,(1)Initially, consulted abundant papers to know more about the biocompatible surfactant and microemulsion and then summarized the latest development and research about the biocompatible microemulsion. Based on this, we chose nonionic surfactant sucrose ester S1570 to mix with anionic surfactant sodium deoxycholate NaDC and explored their phase behaviors using fish diagram and studied various factors' influence on the phase behaviors of the microemulsion. Secondly, we selected biocompatible surfactant Tween 80 mixing with Span 80 to form microemulsion used for entrapment of tea polyphenols which is water-soluble natural antioxidant, to explore the influence on the oxidation resistance of vegetable oil. This exploration may provide a theoretical basis for the application of tea polyphenols in vegetable oil development.(2) The phase behavior of sucrose stearate(S1570)/ isopropyl alcohol/isoamyl acetate/water with ? = 0.5 was investigated at 313 K, and found that emulsification occurs in this system. When the aqueous phase is changed to NaCl solution, the three-phase body appears after the addition of sodium deoxycholate(NaDC) to the S1570 system. And with a less amount of Na DC, the solubilization capacity of the mixed surfactant system is higher. On the other hand, the phase behavior of S1570/NaDC/isopropyl alcohol/isoamyl acetate/NaCl was studied at different temperatures and found that the addition of NaDC changes the temperature sensitivity of the microemulsion system formed using sucrose ester, and with increasing temperature the solubilization capacity of the system increases. The influence of the concentration of NaCl, chain lengh of the oil phase, and oil-water ratio on the phase behaviors was also discussed. Increasing the concentration of NaCl increases the solubilization capacity of the mixed system. With the chain length of oil phase increasing, the monomeric solubility in oil(S1) and the interfacial concentration(S1S) of isopropyl alcohol are all increased, which in turn decreases the solubilization capacity of these systems.(3)Choice n-butyl alcohol as the cosurfactant, the phase behavior of S1570/NaDC/ n-butyl alcohol/amyl acetate/NaCl solution was studied using ?-? fish diagram. The influence of the mass ratio?the concentration of NaCl solution?the chain lengh of oil phase molecule and the chain lengh of alcohol were also explored. It is shown that(1) the solubilization capacity of mixed surfactant system enhanced after the addition of sodium deoxycholate(NaDC) to the S1570 system. With a less amount of NaDC, the solubilization capacity of the mixed surfactant system is higher, and the solubilization capacity reached the highest when the mass ratio of S1570/ NaDC was 8:2.(2) Increasing the concentration of NaCl, the needing of the n-butyl alcohol decreased otherwise the needing of surfactant increased.(3) With the chain length of oil phase increasing, the ability of penetrating and entering the interfacial layer to improve the lipophile property of the interfacial layer for alkane was weaken and the value of SP* was decreased, which in turn decreases the solubilization capacity of these systems.(4)With the chain lengh of alcohol increasing, the ability of controlling the interfacial layer for alcohol was better and the solubilization capacity of the microemulsion increased.(4) The phase behaviors of Tween 80/Span 80/soybean oil?sunflower oil?walnut oil/water system were studied without adding cosurfactant. And use the inverse microemulsion to encapsulate the tea polyphenols which is water-soluble natural antioxidant, to explore the influence on the oxidation resistance of vegetable oil. Using the method of dynamic light scattering tested the particle size of the microemulsion after encapsulating of tea polyphenols and found that the particle size for three vegetable oil microemulsion system were all within 10-100 nm which stated the better stability of the microemulsion system, and with the concentration of tea polyphenols of the microemulsion increasing, the particle size and the polydispersity index were all increasing. By using rheology techniques, the influence of the tea polyphenols on the viscosity of the microemulsion system was explored, and found that the viscosity of three vegetable oil microemulsion system were all reducing with the share rate increasing and last tended to equilibrium, which was pseudoplastic fluid and exhibited a shear-thinning behavior. However, the changing of viscosity of the microemulsion system was not abviously with the concentration of tea polyphenols increasing, which indicated that the influence of the tea polyphenols on the viscosity of the microemulsion system was not abviously. The viscosity of three vegetable oil microemulsion system were all also reducing with elevating the temperature from 283 K to 333 K, which exhibited a heat-thinning behavior. Lastly, the oxidation resistance of vegetable oil microemulsion system encapsulated tea polyphenols was explored and found the tea polyphenols had a good suppression effect on the vegetable oil oxidation. Compared the three vegetable oil microemulsion system, found that tea polyphenols had a best suppression effect on the sunflower oil oxidation. So using inverse microemulsion encapsulated tea polyphenols is a kind of ideal method to vegetable oil oxidation resistance. |
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