Carotenoid content in tritordeum is not primarily associated with esterification during grain development.

Tritordeums show a significant proportion of lutein esters which increases carotenoid stability and retention throughout the food chain. Esterification is a common means of carotenoid sequestration. A putative association between lutein esters formation acting as a metabolic sink during early stages of grain development and the high carotenoid content of tritordeums is analyzed in this work. Compared to wheat, tritordeums accumulated significantly higher lutein contents from 20 days post anthesis (dpa) but lutein esters were not detected until 36 dpa. Thus esterification is not acting as a metabolific sink before 36 dpa. The presence of lutein esters at late stages of grain development may have a complementary role in carotenoid accumulation by reducing and/or counteracting their catabolism. The differences for lutein esterification among tritordeums suggest the existence of diversity for xanthophyll acyl transferases that could be exploited to increase lutein retention in this cereal and through the food chain.