L-cysteine

International Numbering System (INS) for Food Additives: 920

Food additives Europe numbers: E920 

L-cysteine is an interesting food excipient because it can serve several purposes depending on the specific application:

  • Type: L-cysteine is a semi-essential amino acid, a building block of protein. It's naturally found in various foods like meat, poultry, eggs, dairy, and some vegetables.
  • Functions in Food: L-cysteine can act as:
    • Dough Strengthener: It helps strengthen gluten in wheat flour, leading to dough with improved elasticity and handling properties, especially in yeast-leavened baked goods.
    • Flavor Enhancer: L-cysteine can contribute to savory, meaty flavors in certain foods.
    • Antioxidant: It might have some antioxidant properties, potentially helping to slow down spoilage.
  • Safety: Generally recognized as safe (GRAS) by the FDA for its permitted uses in food at specific levels.
  • Regulation: Usage is typically limited and controlled. For example, the FDA restricts its use as a dough strengthener to a specific amount in yeast-leavened baked goods.
  • Source: L-cysteine can be derived from various sources:
    • Animal sources: Traditionally obtained from animal hair, feathers, or hooves (not suitable for vegetarians or vegans).
    • Plant-based fermentation: A more sustainable method uses plant starches and fermentation processes to produce L-cysteine, making it suitable for vegan and vegetarian diets.

Important Considerations:

  • Some people with sensitivities to L-cysteine might experience allergic reactions after consuming foods containing it.
  • It's important to check food labels, especially for those with wheat sensitivities or following specific diets, as L-cysteine might be listed as an ingredient.