Carotenoid changes of colored-grain wheat flours during bun-making

Colored-grain wheat genotypes were used in the preparation of flour, dough, buns, and buns stored for a short period of time. The main carotenoid in all genotypes was lutein, followed by its esters, zeaxanthin, and beta-carotene, while antheraxanthin and alpha-carotene occurred only at negligible levels. The highest carotenoid contents were observed in Yellow- and purple-grained genotypes. After the preparation of dough, total carotenoid content (TCC) decreased significantly by an average of 61.5%. Zeaxanthin was shown to be stable, whereas alpha-carotene was destroyed. In baked buns, the average decrease of TCC and all-E-lutein was lower than in unbaked dough. Greater decreases were recorded for esters, antheraxanthin, and beta-carotene. After storing buns for 24 h at room temperature, approximately one-quarter of TCC observed in the original flour was preserved. Z-Isomers of lutein occurred in minor concentrations, but the degradation of this component, and that of zeaxanthin, was low, suggesting E- to Z-isomerization.