E921 – Cystine (L-) and its hydrochlorides – sodium and potassium salts
Flour bleaching agentDescription
White crystalline powder
Notes
L-cystine is a naturally occurring amino acid that appears as a white crystalline powder. Amino acids are the building blocks of proteins, and L-cystine is found naturally in many protein-rich foods like eggs, poultry, and dairy products. For commercial use, it's typically produced through fermentation processes using bacteria or yeast, or it can be extracted and purified from natural protein sources like human hair, duck feathers, or hog bristles. In food production, L-cystine works as a dough conditioner, which means it helps improve the texture and workability of bread and baked goods. It strengthens the gluten network in dough, making it more elastic and easier to handle, while also helping baked products achieve better volume and texture. You'll find it used in commercial bread production, pizza dough, and various other baked goods where improved dough handling and final texture are important. While L-cystine is a natural amino acid, the commercial source matters for dietary considerations. If derived from human hair or animal sources like feathers or bristles, it wouldn't be suitable for vegetarians, vegans, or those following halal or kosher diets. However, versions produced through fermentation using plant-based processes are available and would be suitable for these dietary requirements. Always check with manufacturers if this is a concern, as the source isn't always clearly labeled on ingredient lists.