I would like to ask if emulsifying, it can be divided into a simple general type. oil in water and water in oil So I suspect that the group สารกันเสีย popular and permitted for use with emulsions as what substances that does not denature the emulsion and then different types of emulsions สารกันเสีย are they the same? The final insertion is with the outer phase, right? What is the approximate percentage by weight? Thank you very much. PS. I'm studying emulsification so I'm afraid that other substances will affect the stability of the emulsion. 