Swedish researchers report that using Saccharomyces cerevisiae strain CBS7764 in white bread can result in folate levels up to 5-fold higher, compared to white bread made with commercial Baker's yeast.
“This strategy is an attractive alternative to fortification of bread with synthetically produced folic acid,” wrote lead author Sofia Hjortmo from Chalmers University of Technology in Stockholm.
Their findings are published in the International Journal of Food Microbiology.
Folate and folic acid during pregnancy are well established to reduce the incidence of neural tube defects (NTD) - most commonly spina bifida and anencephaly.
The connection between the B vitamin and NTDs led to the 1998 introduction of public health measures in the US and Canada, where all grain products are fortified with folic acid - the synthetic, bioavailable form of folate.
While preliminary evidence indicates that the measure is having an effect with a reported 15 to 50 per cent reduction in NTD incidence, parallel measures in European countries, including the UK and Ireland, are still on the table.
Hjortmo and her co-workers formulated breads using S. cerevisiae CBS7764, originally isolated from Rainbow trout intestine, or commercial Baker’s yeast (S. cerevisiae trademark Bla Kronjast).
CBS7764 was cultivated under conditions that favour the folate content, said the researchers.
The bread leavened with CBS7764 was found to contain folate levels three- to five-fold higher than the white bread leavened with commercial Baker’s yeast.
Specifically, the folate content of the CBS7764-leavened bread was between 84–86 micrograms per 100 grams freshweight, reports Hjortmo.
Mandatory US levels for folate are in the range 70–289 micrograms of folate per 100 grams freshweight. Therefore, the high-folate bread produced in this study “is well within this range and would, provided the same bioavailability, therefore be as good folate source as the synthetically fortified products,” wrote the researchers.
“A drawback using folic acid as fortificant is the fact that folic acid can mask a deficiency in vitamin B12, resulting in irreversible neurological damage,” they stated. “No such risks exist when consuming natural, e.g. yeast derived, folates.”
“This strategy is an attractive alternative to fortification of bread with synthetically-produced folic acid,” wrote the researchers.
“By using a high folate producing strain cultured a suitable way folate levels obtained were in accordance with folic acid content in fortified cereal products,” they concluded.
Source: International Journal of Food MicrobiologyVolume 127, Pages 32-36“Biofortification of folates in white wheat bread by selection of yeast strain and process”Authors: S. Hjortmo, J. Patring, J. Jastrebova, T. Andlid