Food emulsifiers: functions, examples, and health effects

Emulsifiers are additives that can be added to processed foods to improve their stability, consistency, and shelf life.[1][2][3]

From a chemical point of view, emulsifiers are surfactants, specifically amphipathic molecules, as they possess both a hydrophilic and a hydrophobic region.[3]

There are over 60 different emulsifiers, and they are among the most commonly used additives in the food industry.[4]

Like other food additives, emulsifiers are identified by their name and/or a code number, known as the E-numbering system, where “E” stands for Europe.[5][6]

The safety of food additives, including emulsifiers, is assessed by competent authorities on the basis of the scientific literature available at the time of evaluation.[7] Recent research has highlighted the need for further studies regarding the long-term safety of certain emulsifiers, as positive association have been observed between their consumption and the risk of cardiovascular disease and inflammatory bowel disease (IBD).[6][8]

Contents

What emulsifiers are

Emulsifiers are surfactants, that is, molecules that reduce the surface tension of a liquid, promoting miscibility between different liquids or the wettability of surfaces.[9]

They are amphipathic (or amphiphilic) molecules, meaning that they contain both a hydrophilic region, soluble in water and characterized by polar groups such as hydroxyl and carboxyl groups, and a lipophilic region, soluble in lipids and characterized by non-polar groups such as methyl groups, methylene bridges, or benzene rings.[1]

Other examples of amphipathic molecules include phospholipids, one of the main components of cell membranes, and bile salts, which are essential in lipid digestion in the small intestine.[10]

What they are used for

Emulsifiers perform multiple functions.

They assist in the dispersion of mutually insoluble phases, namely aqueous and fatty phases, and allow the formation of stable mixtures, whether emulsions, foams, or colloids. By preventing separation between the aqueous and fatty phases in food, they extend shelf life and improve appearance and consistency.[4][9]

Through interactions with food components such as proteins, carbohydrates, ions, and water, emulsifiers also influence other properties of processed foods.
In dairy products, for example, they can displace proteins at air/water and fat/water interfaces, modifying both the properties and stability of the product.[3]
In bread and other baked goods, emulsifiers help improve volume and crumb structure while slowing down starch retrogradation; in bread, this prevents staling.[9]
In chocolate, they improve rheological properties such as deformability and viscosity, and prevent fat blooming, the crystallization of triacylglycerols on the surface of chocolate.[1][11]

The most commonly used emulsifiers include:

  • lecithins, used in chocolate products;
  • monoglycerides and diglycerides of fatty acids (E471), used for example in ice cream;
  • guar gum (E412), added to dairy products;
  • carrageenan (E407), added to ice cream, frozen desserts, flavoured milk, and iced coffee;
  • xanthan gum (E415), used for example in mayonnaise;
  • various types of cellulose (E460–E469), found in food and vitamin supplements;
  • polysorbates (E432–E436), added to products such as icing, chocolate syrup, ice cream, cake mixes, and edible oils.[8][12][13][14]

Natural and synthetic emulsifiers

Emulsifiers, like other food additives, can be of natural origin, derived from either plant or animal sources, or synthetic. Among the emulsifiers of natural origin are lecithins (E322), agar-agar (E406), and guar gum (E412). Examples of synthetic emulsifiers include polysorbates, which are obtained from polyethoxylated sorbitan conjugated with fatty acids such as lauric acid, palmitic acid, oleic acid, or stearic acid.[3][12]
Skeletal formulas of emulsifiers used in food, such as alginic acid, carrageenan, and polysorbate 80.Several emulsifiers are obtained by chemically modifying natural compounds, which alters their original properties. Examples include sucrose esters (E473) and sucroglycerides (E474).[14]

Health effects

In vitro and mouse studies, as well as population studies, have shown that certain emulsifiers may have potential adverse effects on the gastrointestinal and cardiovascular systems.
However, evidence in humans is still limited and not all emulsifiers have the same effects, with regulatory agencies considering approved levels to be safe.

The consumption of processed foods containing emulsifiers is among the factors thought to contribute to the development of inflammatory bowel disease.[8] Proposed mechanisms include changes in the gut microbiota and/or dysfunction of the intestinal barrier, allowing the passage of bacteria and increasing antigen exposure, as suggested by both mechanistic hypotheses and experimental studies. These alterations may contribute to low-grade inflammation, a factor implicated in metabolic and gastrointestinal disorders.[14][15][16]

A prospective cohort study found a positive association between high intakes of cellulose and of monoglycerides and diglycerides of fatty acids, respectively, and the risk of coronary heart disease and cerebrovascular disease.[6]

Further studies are needed to clarify which emulsifiers may pose risks and under what conditions.

References

  1. ^ a b c Belitz H.-D., Grosch W., Schieberle P. Food Chemistry. 4th Edition. Springer, 2009.
  2. ^ Commission Regulation (EU) No 1129/2011 of 11 November 2011 amending Annex II to Regulation (EC) No 1333/2008 of the European Parliament and of the Council by establishing a Union list of food additives. https://eur-lex.europa.eu/eli/reg/2011/1129/2013-11-21
  3. ^ a b c d Hasenhuettl G.L. and Hartel R.W. (Eds.). Food emulsifiers and their applications. 3rd Edition New York: Springer, 2008.
  4. ^ a b Sandall A., Smith L., Svensen E., Whelan K. Emulsifiers in ultra-processed foods in the UK food supply. Public Health Nutr 2023;26(11):2256-2270. doi:10.1017/S1368980023002021
  5. ^ Food Standards Agency. Approved additives and E Numbers. Last updated: 16 July 2025.
  6. ^ a b c Sellem L., Srour B., Javaux G., et al. Food additive emulsifiers and risk of cardiovascular disease in the NutriNet-Santé cohort: prospective cohort study. BMJ 2023;382:e076058. doi:10.1136/bmj-2023-076058
  7. ^ EFSA Food additives: EFSA’s new guidance for applicants. Published: 18 July 2012. https://www.efsa.europa.eu/en/press/news/120718a
  8. ^ a b c Bancil A.S., Sandall A.M., Rossi M., Chassaing B., Lindsay J.O., Whelan K. Food additive emulsifiers and their impact on gut microbiome, permeability, and inflammation: mechanistic insights in inflammatory bowel disease. J Crohns Colitis 2021;15(6):1068-1079. doi:10.1093/ecco-jcc/jjaa254
  9. ^ a b c Damodaran S., Parkin K. Fennema’s Food Chemistry. 5th Edition. CRC Press, 2017.doi:10.1201/9781315372914
  10. ^ Nelson D.L., Cox M.M. Lehninger. Principles of biochemistry. 8th Edition. W.H. Freeman and Company, 2021.
  11. ^ Trapp L., Karschin N., Godejohann M., Schacht H., Nirschl H., Guthausen G. Chemical composition of fat bloom on chocolate products determined by combining NMR and HPLC-MS. Molecules 2024;29(13):3024. doi:10.3390/molecules29133024
  12. ^ a b Cox S., Sandall A., Smith L., Rossi M., Whelan K. Food additive emulsifiers: a review of their role in foods, legislation and classifications, presence in food supply, dietary exposure, and safety assessment. Nutr Rev 2021;79(6):726-741. doi:10.1093/nutrit/nuaa038
  13. ^ EUFIC What are emulsifiers and what are common examples used in food? Last Updated: 01 October 2022.
  14. ^ a b c Partridge D., Lloyd K.A., Rhodes J.M., Walker A.W., Johnstone A.M., Campbell BJ. Food additives: assessing the impact of exposure to permitted emulsifiers on bowel and metabolic health – introducing the FADiets study. Nutr Bull 2019;44(4):329-349. doi:10.1111/nbu12408
  15. ^ Csáki K.F. Synthetic surfactant food additives can cause intestinal barrier dysfunction. Med Hypotheses 2011;76(5):676-81. doi:10.1016/j.mehy.2011.01.030
  16. ^ Roberts C.L., Keita A.V., Duncan S.H., O’Kennedy N., Söderholm J.D., Rhodes J.M., Campbell B.J. Translocation of Crohn’s disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers. Gut 2010;59(10):1331-9. doi:10.1136/gut.2009.195370

Biochemistry and Metabolism