E105 is a derivative of riboflavin (vitamin B2), an essential vitamin that plays a critical role in energy metabolism and the maintenance of healthy skin, eyes, and nervous system. Riboflavin itself is a naturally occurring compound found in various foods, including eggs, green leafy vegetables, nuts, and dairy products. The phosphate ester form, E105, is water-soluble and is often synthesized for use in food production. This additive can impart a bright yellow to orange hue to food products, making them visually appealing.