What is L-Cysteine?
What is L-cysteine and is it a safe ingredient for Muslims to consume?
L-cysteine and the corresponding disulfide L-cystine, are non-essential amino acids that can be formed in the body through the conversion of the essential amino acid methionine. L-cysteine hydrochloride is used in the baking industry as a dough conditioner. Specially, it breaks the disulfide bonds of gluten, which lowers the viscosity of the dough. It is then easier to work with and increases the elasticity of the dough, helping it to rise during baking.
L-cysteine is used in bagels, sliced bread, croissants, hard rolls, pita bread, crackers, etc. It is also used as a nutrient in baby milk formula and dietary supplements.
Ten years ago the most common way to obtain L-cysteine on industrial scale was through hydrolysis of human hair found on the floors of barbershops in China.
Today, the primary source of this amino acid is goose and duck feathers; however, human hair, swine bristles, and swine hooves have also been identified as sources. These latter sources are not used in Canada*. There is also a vegetarian source manufactured through a fermentation process, but due to cost and availability, it is not used widely.
According to Islamqa.org, it is NOT permissible to consume L-cysteine or any product which contains L-cysteine derived from human hair extracts because the human body is to be honored and revered at all times. Furthermore, L-cysteine derived from pig would also not be halal since every part of the pig is considered impure in Islam.
If L-cysteine is produced from the hair or feather extracts of any animal besides pig, whether the animal was halal slaughtered, died a natural death or the animal was incorrectly slaughtered, it is permissible.
It will also be permissible to consume L-cysteine or any product which contains L-cysteine if it is produced synthetically since it is not produced from any impure or haram (forbidden) substance.
Unless L-cysteine is derived from syntheitc sources, it would not be considered vegetarian. However, for Muslims living in Canada, we can rest a little easier knowing that most if not all the L-cysteine used in Canadian manufacturing is from goose and duck feathers.
Source: Islamqa.org and the *Baking Association of Canada