Polyglycerols were known since the beginning of the twentieth century. However, it is only in the last decade that high purity products were developed. This led to their increasing use in the form of polyglycerol esters in many food applications.
Polyglycerol esters are non-ionic surfactants that are allowed for food use in many countries. In addition to the stabilization of emulsions, foams, and dispersions, polyglycerol esters can act as aerating agents, dough strengtheners, rheology modifiers, crystal modifiers, anti-spattering agents, beverage clouding agents, humectants, solubilizers, or fat substitutes.
Furthermore, they are biodegradable, biocompatible, and free from ethylene oxide and nitrosamines. Note that Solvay produces Diglycerol and Polyglycerol-3 but not their ester derivatives. For additional information about the composition and unique properties of Solvay Polyglycerols, please refer to our other product and Technical Data Sheets on the web site posted at the bottom of the page.
Polyglycerol esters have been used as food additives for many years. From the legal point of view, food grade polyglycerol esters are divided in 2 classes: polyglycerol esters of edible fatty acids (E-number: E475, also known as “PGFA”) and polyglycerol polyricinoleate (E-number: E476, also known as “PGPR”).
Depending upon their HLB, polyglycerol esters can act as water-in-oil (W/O) or oil-in-water (O/W) emulsifiers. As mentioned in the “Polyglycerols for ester production” Application Data Sheet, Diglycerol and Polyglycerol-3 esters allow a strong interfacial tension reduction between water and a wide variety of oils. In many systems, they have an even better surface activity than glycerol or homologous polyol esters.3,4
Diglycerol and Polyglycerol-3 esters also form highly stable α-gels in water, while gels produced from glycerol monostearate transform with time into a β-crystal structure called coagel.5,6 The high stability of α-gels is a key advantage of polyglycerol esters in food applications. Indeed, it leads to better emulsification properties and a higher viscosity of the external water phase, resulting in enhanced stabilization of O/W emulsions and foams.
Polyglycerols in Food Applications
The most popular food grade PGFAs are Diglycerol and Polyglycerol-3 monostearates. When mixed with water, these emulsifiers form highly stable α-gels and exhibit α-tending properties. These esters are of special interest, for example in sponge cake technology, where they lead to an optimal stabilization of the batter and a more uniform foam structure.The superior performance of esters based on Solvay polyglycerols is likely due to several reasons: Lower content in glycerol., Lower content in high molecular weight oligomers, Lower content in cyclic byproducts, Indeed, the following results, using fresh gels, show the detrimental effect of cyclic and long chain polyglycerols on cake quality.
Other typical food applications
In addition to the previously described applications, polyglycerol esters can be used in: Whipped products, in which they act as emulsifiers and aerating agents for the manufacture of stable foams with softer textures, Ice creams, to improve foaming, stability and texture,Refined salad and cooking oils, as crystallization inhibitors,Dressings, to improve their freezing and thaw stability,Beverage whiteners, to improve their stability and their dispersibility in coffee,Coatings and glazes, to which they confer improved workability, gloss, gloss life, and stability, Reduced-fat foods, in which they contribute to their stability, texture and mouth-feel, Chewing gums, as softeners and to avoid sticking to teeth.