Abstract:

Lutein exists in nature mostly in the form of lutein esters. Fortification of bread with lutein esters can improve
dietary lutein intake. To investigate the stability of lutein esters in fortified bread during processing and subsequent storage,
lutein and its stereoisomers as well as lutein esters were analyzed during dough processing, fermentation, baking and storage.
The results showed that lutein esters were stable, and the retention rates of total lutein and trans-lutein after saponification
were higher during dough processing and fermentation process. Baking caused a slight decrease in lutein esters in bread crust
and core and a significant decline in the retention rates of total lutein and trans-lutein after saponification. The generation
of cis-isomers was found during the whole processing and storage process of fortified bread. A small amount of 13-cis- and
13’-cis-lutein were generated during dough making, and a small number of 9-cis- and 9’-cis-lutein were detected during
fermentation. Similarly, baking caused a significant increase in 13-cis-, 13’-cis-, 9-cis- and 9’-cis-lutein. The contents of
lutein esters, lutein, trans-lutein and its cis-isomers declined slightly throughout the whole storage period.

Key words: lutein esters, fortified bread, processing, storage, stability