E101

E101 is the European food additive code for riboflavin, also known as vitamin B2. It is a water-soluble vitamin and a natural yellow pigment used in foods and animal feeds as both a nutrient and a colorant. As a food additive, E101 is valued for its ability to impart a yellow color and to contribute to the dietary riboflavin content of products.

Common uses include fortifying cereals, dairy products, baked goods, confectionery, beverages, and processed foods that require a yellow hue. It is also used in some infant formulas and breakfast mixes in certain jurisdictions. In addition to human foods, riboflavin is employed as a feed additive to improve the riboflavin content of animal diets.

Chemically, riboflavin is a flavin derivative with the formula C17H20N4O6. It exists as a yellow crystalline powder and is water-soluble. It is sensitive to light, which can cause fading of color, and it functionally serves as a cofactor in the body in the forms FMN and FAD, supporting energy metabolism and redox reactions.

Regulatory and safety notes vary by jurisdiction. In the European Union, E101 is approved under specific purity criteria for use as a coloring agent and fortificant. As a vitamin, riboflavin is essential for health, and excess intake is generally excreted in urine. High-dose supplementation is rarely associated with adverse effects, though excessive exposure can lead to harmless urine discoloration. Storage recommendations typically emphasize protection from light to preserve color stability.