| Vitamin E is one kind of essential nutrients, which has many physiological functions such as scavenging free radicals, anti-aging, protecting the skin from the sun radiation damage, enhancing immunity and preventing cancer. However, it is insoluble in water, which greatly limits its application in the food industry. Dilutable microemulsion can significantly increase solubility of fat soluble nutrients including vitamin E. These microemulsions containing such nutrients can be dissolved in water to form isotropic, transparent and stable solution.This paper chose vitamin E acetate (VE), one common form of vitamin E, as the embedding object. The formula of VE microemulsion was optimized by pseudoternary phase diagram and dynamic scattering technology, including surfactant types and the proportion of surfactant and co-surfactant (Km) as well as surfactant and VE (S/O). The results indicated that the optimum formula consisted of VE, Cremophor RH40 and ethanol (Km=3 and S/O =4:3). The loading capacity of VE was 36%. The average particle size of the formula was about 46 nm (PDI = 0.26).The phase characteristic of the dilutable VE microemulsion in the process of dilution by water was examined through the use of electrical conductivity, rheology and dynamic light scattering. The data revealed that the classification results of the three methods were approximately the same. When the water content wasΦ< 20%, W/O microemulsion was obtained. While the system with water contentΦbetween 20% and 72%, resulted in the formation of a bicontinuousin; that ofΦ> 72%, formed O/W microemulsion. At the same time, the affects of the addition orders of microemulsion components on the dilutable microemulsion formation ability were studied by pseudoternary phase diagram and dynamic scattering technology using six oils with different chain length as oil phase and Cremophor RH40/ethanol (Km = 3) as surfactant. The experimental results showed that for short chain oils such as ethyl acetate and ethyl butyrate, the addition orders had no effect; but for long chain oils, such as ethyl laurate, ethyl oleate and vitamin E acetate, the method of oil titration basically could not form dilutable microemulsion when the water content was more than 40%.For the VE microemulsion enzyme hydrolysis experiment it was noted that the release of vitamin E biological activity from VE microemulsion was significantly better than ordinary VE emulsion. After 300 min of enzyme hydrolysis, the free radicals clearance of O/W type VE microemulsion amounted to 90% while the ordinary VE emulsion scavenged below 60%. The observed improvement of biological activity of the former system strongly enhanced the enzyme hydrolysis reaction promoted by the mcroemulsion structure. In addition, when dissolution rate of different dilutable VE microemulsion formulas were compared, ethanol was found to accelerate the phase transition process. The time for dissolution of VE microemulsion was reduced from more than 6 min to less than 2 min upon addition of ethanol.Finally, the effects of the processing conditions, such as temperature, pH, salt concentration and sugar concentration on the particle size of O/W type VE microemulsion were inspected. Also, its storage stability was investigated. The results showed that in 25-85 oC, pH from 3 to 7, NaCl concentration c≤2 mol/L, sugar concentrationω≤20% and storage of 120 days, the particle size of the microemulsion remained basically the same. Under these conditions, the O/W type VE microemulsion exhibited good stability. |
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