Genetic variability of carotenoid concentration and degree of esterification among tritordeum (xTritordeum Ascherson et Graebner) and durum wheat accessions

The higher carotenoid content (commonly referred as "yellow pigment content") of tritordeum seeds as compared to wheat and the potential of this species as a donor of useful traits to wheat led us to investigate the detailed carotenoid composition of 53 accessions of hexaploid tritordeums originating from different stages of the tritordeum breeding program developed at IAS-CSIC. In addition, seven durum wheat accessions were also studied for comparison. Lutein was the unique carotenoid detected, either free or esterified with fatty acids. On average, tritordeum had 5.2 times more carotenoids than durum wheat, which suggests a high potential of this species to become a functional food. In addition, the most outstanding result of this work is the high esterification degree of lutein found in tritordeums as compared to durum wheat. This difference may indicate the differential esterification ability between tritordeum and durum wheat species. The implications of this high level of lutein esterification on both carotenoid accumulation and stability are discussed.