Abstract:

Pseudo ternary phase diagram was conducted using water titration method to choose emulsifier EL-35-ethyl butyratewater system to prepare β-carotene liquid crystal, and the microstructures and rheological properties of 4 emulsifier EL-35-ethyl butyrate-water systems (A1, A2, A3 and A4) with different water masses (the mass ratio of emulsifier EL-35 to ethyl butyrate were fixed at 5:5) were characterized with polarizing microscopy and rheometer. Effects of external conditions, including pH value, preservative (sodium benzoate), saturated ethyl butyrate solution of β-carotene and water amount on stability of this system were discussed. Furthermore, effects of sunlight and pH on the stability of β-carotene were compared in different multiphase systems, including liquid crystal, microemulsion and ethyl butyrate solution. Results revealed that the optimal mass ratio of EL- 35 to ethyl butyrate to water was 1:1:1, and other three external conditions had little effects on the stability of emulsifier EL-35- ethyl butyrate-water system. β-carotene contained in liquid crystal was sensitive, but more stable to light at 25 ℃ than that in ethyl butyrate solution and in microemulsion. pH value exhibited marked effects on the stability of the latter two, but little effect on that of the former. Therefore, liquid crystal presents a convenient and nontoxic vehicle for β-carotene in food industry.

Key words: β-carotene, lytropic liquid crystal, preparation, stability