Isolation and identification of lutein esters, including their regioisomers, in tritordeum (×Tritordeum Ascherson et Graebner) grains: Evidence for a preferential xanthophyll acyltransferase activity

► The major carotenoid in tritordeum was lutein, in free form and esterified with fatty acids. ► MS fragmentation patterns allow the structural assignment of lutein ester regioisomers. ► Lutein ester regioisomers have been isolated and identified for the first time in a cereal. ► Evidence for a preferential xanthophyll acyltransferase activity has been deduced.