Free and esterified carotenoids in pigmented wheat, tritordeum and barley grains

- Purple wheat varieties and breeding lines contained higher levels of carotenoids than blue ones.
- Purple wheat varieties and breeding lines were high in esterified forms of xanthophylls.
- Lutein was predominant in wheat and tritordeum while zeaxanthin in barley.
- Antheraxanthin was quantified at very low levels in mature cereal grain.
- High temperature and drought during the growing season promoted carotenoid biosynthesis.

Carotenoids are important phytonutrients responsible for the yellow endosperm color in cereal grains. Five carotenoids, namely lutein, zeaxanthin, antheraxanthin, α- and β-carotene, were quantified by HPLC-DAD-MS in fourteen genotypes of wheat, barley and tritordeum harvested in Czechia in 2014 and 2015. The highest carotenoid contents were found in yellow-grained tritordeum HT 439 (12.16 μg/g DW), followed by blue-grained wheat V1-131-15 (7.46 μg/g DW), and yellow-grained wheat TA 4024 (7.04 μg/g DW). Comparing carotenoid contents, blue varieties had lower whereas purple ones had the same or higher levels than conventional bread wheat. Lutein was the main carotenoid found in wheat and tritordeum while zeaxanthin dominated in barley. The majority of cereals contained considerable levels of esterified forms (up to 61%) of which lutein esters prevailed. It was assessed that cereal genotype determines the proportion of free and esterified forms. High temperatures and drought during the growing season promoted carotenoid biosynthesis.