Published in the Food Chemistry, researchers from Canada investigated the bioaccessibility of lutein-enriched muffins, cookies and flatbreads made from carotenoid-rich einkorn wheat and further fortified with pure lutein.
In vitro tests found bioavailability was higher in muffins and cookies – a finding that was “due to their elevated fat content”, researchers said.
Extensive lipid digestion, they explained, meant more lutein was solubilized which in turn increased its bioavailability.
This, they said, was consistent with previous evidence that suggested fat content was an important determinant of bioaccessibility, especially where lipid digestion was extensive.
In addition, they said several other factors could have contributed to differing lutein levels in each bakery product.
“The form of lutein (e.g. free versus ester or powder versus oil-based) could affect distribution and concentration of lutein in the end product. In the current study, free lutein in corn oil suspension was emulsified with whey protein and a small portion of water before being added to the baking formula to improve the carotenoid’s distribution. This practice was effective in cookies and muffins but not in flatbread,” they explained.
High-fat but better for you…
The researchers said these findings were important, particularly as global health problems were a growing concern.
“In light of the rising incidences of obesity and the associated metabolic disorders, the appropriateness of high fat baked products marketed as vehicles for bioactive delivery warrants consideration,” they wrote.
They said carotenoids like lutein – important for promoting eye and skin health – were “essential for human health and must be provided in the diet”.
Inclusion into commonly consumed baked goods could change low carotenoid consumption rates, they said.
Formulation knowledge crucial for best bioavailability
The researchers said a strong understanding on how baked good compositions and microstructure impacted lutein digestion and absorption was needed to support the successful design of functional products.
“Incorporation of lutein into the baking formula is a challenge because of its lipophilicity and difficulty in evenly distributing it in a dough or batter system,” they said.
There were also distinct differences between ‘fed’ and ‘fasted’ states on bioavailability. All baked goods showed better bioavailability of lutein in a fed state due to the presence of additional bile salts and phospholipids which contributed to enhanced lipid solubilisation, the researchers said.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2014.11.074
“In vitro bioaccessibility and monolayer uptake of lutein from wholegrain baked foods”
Authors: A. Read, A. Wright and EM. Abdel-Aal