Food-grade Glycerin

Glycerin is a versatile ingredient commonly used in the food industry. It is a natural substance that has been employed for many years. It imparts very interesting properties to the foods in which it is used. Glycerin is made up of three carbon atoms, each bonded to a hydroxyl group. It forms the backbone of the most abundant fats and oils in living organisms, known as acylglycerols. It is also known as glycerol, 1,2,3-propanetriol, trihydroxypropane, or E-422.

At temperatures above 18°C, it is a transparent viscous liquid that is fully soluble in water. It has a sweet taste, about 65% as intense as that of sucrose. The European regulation that governs its use in food is Regulation (EC) No. 1333/2008. It is listed in Annex I, which means it can be used without a maximum dosage limit in many food products.

The European Food Safety Authority (EFSA) has recently reevaluated glycerin as a food additive on two occasions (in 2017 and 2022). It considers glycerin to be a safe additive with no adverse effects, and for which it has not set an Acceptable Daily Intake (ADI). There are no toxicological, genotoxic, or carcinogenic concerns. EFSA recommends reducing the limits of certain contaminants and refining glycerin through distillation and washing. The raw materials used to obtain glycerin must be of either animal or plant origin.

Glycerin is considered a hypoallergenic ingredient, and allergic reactions to it are very rare (see here and here). To be approved for use in food within the European Union, glycerin must meet the EU’s identity and purity criteria. One of its quality indicators is its water content: the upper limit is 5%, and the less water it contains, the better.

The main applications of glycerin in the food industry are as follows:

• In beverages, it adds body to the liquid, enhancing its palatability.

• In ice cream, it acts as an antifreeze agent by preventing crystal formation, softens the texture, and adds body.

• In baked goods and pastries, it is primarily used as a humectant. In cupcakes, sponge cakes, and whipped batters, it retains moisture and helps keep the products juicy for longer. It extends shelf life by preventing dryness and brittleness.

• In fondant, glycerin softens the texture and adds elasticity, making it easier to handle and mold. It also prevents the surface from drying out.

• In confectionery, it works as a plasticizer and humectant. It prevents sugar crystallization and hardening and helps keep surfaces soft and flexible.

Although there is no dosage limit, the recommended amount of glycerin in food products generally ranges between 0.5% and 3%. The exact amount may vary depending on environmental humidity: in drier environments, a higher amount may be used to help prevent food from drying out. However, it is important to note that excessive glycerin can make the product too sticky or soft. Too much glycerin may also cause the food to absorb water from the air, affecting its properties and shortening its shelf life.

Excessive intake of glycerin is not toxic, but very high doses may cause diarrhea. The effects of glycerin on food described above are due to the hydroxyl groups in its molecule, which form hydrogen bonds with water molecules. This affinity for water explains its humectant effect. Additionally, glycerin reduces water activity, which contributes to preservation by lowering the amount of free water needed for microbial growth.