IUPAC Name:  (2E,4E,6E,8E,10E,12E,14E,16Z,18E)-4,8,13,17-Tetramethylicosa-2,4,6,8,10,12,14,16,18-nonaenedioic acid
The MF of Annatto (CAS NO.1393-63-1) is C₂₄H₂₈O₄.

                  
The MW of Annatto (CAS NO.1393-63-1) is 380.4767.
Synonyms of Annatto (CAS NO.1393-63-1): (2E,4Z,6E,8E,10E,12E,14E,16E,18E)-4,8,13,17-Tetramethylicosa-2,4,6,8,10,12,14,16,18-nonaenedioic acid ; 2,4,6,8,10,12,14,16,18-Eicosanonaenedioic acid, 4,8,13,17-tetramethyl-, (2E,4Z,6E,8E,10E,12E,14E,16E,18E)-

 Annatto has long been used by indigenous Caribbean and South American cultures. It is believed to originate in Brazil. It was probably not initially used as a food additive but for other reasons, such as body painting, to ward off evil, and as an insect repellent.The ancient Aztecs called it achiotl, and it was used for Mexican manuscript painting in the sixteenth century.

 Annatto (CAS NO.1393-63-1) is used to produce a red food coloring and also as a flavoring.Annatto is commonly found in Latin America and Caribbean cuisines as both a coloring agent and for flavoring. 
 In Venezuela, annatto (called locally onoto) is used in the preparation of hallacas, perico, and other traditional dishes. In Brazil, both annatto (the product) and the tree (Bixa orellana L.) are called urucum and the product itself may also be called colorau. In the Caribbean islands, both fruit and tree are popularly called achiote or bija (pronounced "bee-ha") instead of Bixa. In the Philippines, it is called atsuete and is used as food coloring in traditional dishes.

 Annatto is produced from the reddish pulp which surrounds the seed of the achiote (Bixa orellana L.). It is used in many cheeses (e.g., Cheddar, Red Leicester, and Brie), margarine, butter, rice, smoked fish, and custard powder.

Reported in EPA TSCA Inventory.

Mutation data reported. When heated to decomposition it emits acrid smoke and irritating vapors. Annatto has been linked with many cases of food-related allergies, and is the only natural food coloring believed to cause as many allergic-type reactions as artificial food coloring. Because it is a natural colorant, companies using annatto may label their products "all natural" or "no artificial colors".

 Annatto, sometimes called Roucou, is a derivative of the achiote trees of tropical regions of the Americas, used to produce a red food coloring and also as a flavoring. Its scent is described as "slightly peppery with a hint of nutmeg" and flavor as "slightly sweet and peppery".
 Annatto is commonly found in Latin America and Caribbean cuisines as both a coloring agent and for flavoring. Central and South American natives use the seeds to make a body paint, and lipstick. For this reason, the achiote is sometimes called the lipstick-tree. Achiote originated in South America and has spread in popularity to many parts of Asia. The heart-shaped fruits are brown or reddish brown at maturity, and are covered with short, stiff hairs. When fully mature, the fruits split open exposing the numerous dark red seeds. While the fruit itself is not edible, the orange-red pulp that covers the seed is used as a commercial food coloring and dye (similar to turmeric). The achiote dye is prepared by stirring the seeds in water.