E920 – Cysteine
StabiliserDescription
L-Cysteine is a sulfur-containing, non-essential amino acid used primarily as a dough conditioner (reducing agent) in baking to break disulfide bonds in gluten proteins, improving dough extensibility, reducing mixing time, and preventing shrinkage in processed goods. It is also used as an antioxidant and as a precursor in flavor development, particularly savory flavors. E920 is typically produced via microbial fermentation or hydrolysis of protein sources (historically human hair or poultry feathers).
Notes
L-Cysteine is a sulfur-containing amino acid that can be obtained from several sources. Historically, it was often derived from human hair, duck feathers, or hog hair through an acid treatment process that breaks down the keratin proteins to release the cysteine. Today, much of the commercial L-cysteine used in food is produced through fermentation using genetically modified bacteria or yeast, which is a more controlled and consistent method similar to how we make other fermented ingredients like citric acid. In baking, L-cysteine works as a dough conditioner and reducing agent, meaning it helps break down the gluten proteins in flour to make dough more pliable and easier to work with. This results in bread and baked goods with better texture, improved volume, and easier industrial processing. You'll primarily find it in commercial breads, pizza doughs, bagels, and other wheat-based products where dough needs to be stretched or shaped efficiently. The source of L-cysteine is crucial for dietary considerations. While the synthetic versions produced through bacterial fermentation are generally suitable for vegetarians and vegans, those derived from animal sources (hair, feathers) are not. Additionally, L-cysteine from human hair raises concerns for some religious dietary laws. Many manufacturers now clearly indicate the source on ingredient lists, and the trend is moving toward synthetic production methods. The additive is considered safe by food regulators when used within approved limits.