| The objective of this study was to produce a kind of O/W microemulsion of Glycerol monolaurate above 90 percent content of monoester as a raw material by the technology of microemulsification. The resulted product is Glycerol monolaurate (GML) microemulsion , which will significantly enhance the effect of anti-bacteria of GML.The optimum GML microemulsion was obtained according to the following steps. Firstly, Glycerol monolaurate above 90 percent content of monoester was derived by low-temperature-crystallization method for three times from about 45 percent content of monoester as a raw material.Secondly, O/W microemulsion was made. The process was divided into three stages: at first cosurfactant (alcohol) was selected according to the physical properties of GML. Then a kind of food surfactant or several that apt to forming microemulsion were adopted by their values of HLB. At last , orthogonal experiments were done to determine the optimum ingredients for GML microemulsion, that is ,the ratio of oil to surfactant to water to cosurfactant is 1 to 4.5 to 4 to 3.Thirdly, under the optimum ingredients, GML microemulsion was produced. The test of anti-bacteria was done in order to assay the effect of inhibiting microcreature of microemulsion with black, GML(45 percent content of monoester), GML(90 percent content of monoester), a common emulsion of GML and common preservatives such as Patassium sorbate , Nipagin esters as control group. And the result was proved that the microemulsion had stronger efficacy of anti-bacteria. The stability of GML microemulsion was assayed by two ways. One is thatmicroemulsion being stored for some time was observed whether there was a phenomenon of separating phase. Another is the experiment of anti-bacteria to GML microemulsion with being put some time in different temperatures. The results of both tests were showed that the microemulsion had better stability. Application the microemulsion into the food such as sticky-rice cakes was also studied and it could obviously delay the shelf-life of these cakes. |
