1911 Encyclopædia Britannica/Anatto
ANATTO (possibly a native American name, with many variants such as annatto, arnotto), a colouring matter produced from the seeds of Bixa orellana (natural order Flacourtiaceae), a small tree which grows in Central and South America. The seeds are surrounded with a thin coating of a waxy pulp, which is separated from them by washing in water, passing the liquid through a sieve and allowing the suspended pulp to deposit. The water is then drained away and the paste dried, till it is a thick, stiff, unctuous mass. In this state it has a dark orange-red colour and is known as “roll” or “flag” arnotto, according to the form in which it is put up, but when further dried it is called “cake” arnotto. Arnotto is much used by South American Indians for painting their bodies; among civilized communities its principal use is for colouring butter, cheese and varnishes. It yields a fugitive bright orange colour, and is to some extent used alone, or in conjunction with other dyes, in the dyeing of silks and in calico printing. It contains a yellow colouring matter, bixin, C16H26O2.