Glycerol

What it is

Glycerol (E422), also known as glycerin, is a simple polyol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. In food, it is primarily used as a humectant—an agent that holds onto water and prevents food from drying out.

How it is used in food

In food it holds moisture — it’s why protein bars stay chewy for months.

• Protein bars and energy bars (keeps them chewy instead of rock-hard)
• Fondant icing and cake decorations
• Marshmallows and soft candies
• Dried fruits

Health and safety

None known.

Completely natural metabolic product.

Regulatory status

Identification on labels

E-number

E422

Also printed asGlycerin · Glycerine

Alternatives to this additive

• E420: Sorbitol — Another sugar alcohol that functions as a humectant and sweetener.
• E1520: Propylene glycol — A synthetic humectant often used in flavor extracts.

How it is made

Glycerol forms the "backbone" of all triglyceride molecules (dietary fats). It is commercially produced as a byproduct of soap manufacturing or biodiesel production from plant oils or animal fats.

1. Saponification or Hydrolysis — Triglycerides (fats and oils) are reacted with water under high pressure, or with an alkali (like lye in soap making).
2. Separation — The fatty acids separate from the glycerol backbone.
3. Purification — The crude glycerol is distilled and filtered through activated carbon to produce pure, food-grade glycerin.

Worth knowing

The backbone molecule of all fats, released whenever fat is digested.

Conclusion

E422 is a safe and effective humectant. Like E471, it can theoretically be derived from animal fats, so strict vegans look for plant-derived or certified vegan sources.

References

• EFSA re-evaluation of glycerol (E 422) — EFSA