Annatto is an orange-red colourant derived from the seeds of the achiote tree (Bixa orellana). The reddish orange colour dye of the annatto mainly comes from the resinous outer covering of the seeds of the plant. The yellow to orange colour is produced by the chemical compounds bixin and norbixin, which are classified as carotenoids. The lipophilic colour is called bixin, which can then be saponified into water-soluble norbixin. This dual solubility property of annatto is rare for carotenoids. The seeds contain 4.5–5.5% pigment, which consists of 70–80% bixin. Unlike beta-carotene, another well-known carotenoid, annatto-based pigments are not vitamin A precursors. The more norbixin in an annatto color, the more yellow it is; a higher level of bixin gives it a more orange shade.