Norbixin is a carotenoid dicarboxylic acid derived from the alkaline hydrolysis of bixin, the primary pigment in annatto seeds (Bixa orellana). It serves as a natural food colorant (E160b) imparting yellow to orange hues in aqueous systems such as cheeses, beverages, and processed foods. Structurally, it consists of a conjugated polyene chain with terminal carboxylic acid groups, conferring water solubility especially in alkaline conditions where it forms salts. Unlike the lipophilic bixin, norbixin is hydrophilic and exhibits antioxidant properties due to its extended conjugation. It is stable under neutral to alkaline pH but may degrade under strong light or acidic conditions. Regulatory bodies including FDA and EFSA approve its use with established ADI limits.