Group: E100–E199 (colours)
E101(i) is a food additive approved by the European Union (EU). It is used as natural colouring agents in food products. The common name for E101(i) is Riboflavin. E101(i) is better known as vitamin B2. These colourings occur naturally in liver, kidney, eggs, milk and vegetables. They can also be prepared industrially by synthesis of certain yeasts. E101 gives foods a yellow colour but its use is limited by its low solubility. E101 in the diet is essential in order for antibody production and for the formation of red blood cells.

E101(ii) or E101a is a food additive approved by the European Union (EU). It is used as natural colouring agents in food products. The common name for E101 (ii) is Riboflavin-5'phosphate. These colourings occur naturally in liver, kidney, eggs, milk and vegetables. They can also be prepared industrially by synthesis of certain yeasts. E101 gives foods a yellow colour but its use is limited by its low solubility. E101 in the diet is essential in order for antibody production and for the formation of red blood cells.