Food additives are: in order to improve the quality of food and color, aroma and taste, as well as in order to preservative, freshness and processing needs to be added to the food in the synthetic or natural substances, food flavors, gum-based confectionery base agent substances, food industry processing aids are also included. For example: nitrite, sodium benzoate, Tween 60, etc. are food additives.

Emulsifier means: can improve the emulsification system in a variety of constituent phases of the surface tension between the formation of a uniform dispersion or emulsion of the substance. Examples include: ammonium phospholipids, propylene glycol, and so on.

The above content from the "GB 2760-2014 food safety national standards for the use of food additives"