Friendly bacteria may blunt fibre’s anti-nutrient actions
While the consumption of whole-grain bread or fibre-enriched bread is increasing on the back of consumer understanding of the benefits of a high-fibre diet, wholegrain foods are also reported to impair mineral absorption. The impairment is thought to be related to the phytate and phytic acid content of these products.
According to new findings published in the Journal of Agricultural and Food Chemistry phytase enzymes produces by strains of bifidobacteria, which are GRAS/QPS (generally regarded as safe/ qualified presumption of safety), could reduce phytate and phytic acid levels in bread.
Furthermore, the technological and sensorial qualities of the phytase-reduced bread were similar to the control bread, report the researchers, led by Monika Haros from the Cereal Group at the Institute of Agrochemistry and Food Technology in Valencia.
“The commercial phytases, which are used as feed additives, are not added to foods meant for human consumption,” they wrote.
“Therefore, Bifidobacterium strains or the enzyme preparations would be the best approach to reduce the content of phytic acid in fibre-rich products for human consumption.”
The majority of the science supporting the consumption of wholegrains focuses on heart health. This has already led the FDA to permit foods containing at least 51 percent whole grains by weight and that are low in total fat, saturated fat, and cholesterol to carry a health claim linking them to a reduced risk of heart disease and certain cancers.
The term wholegrain is considered to be more consumer-friendly than the term fibre, which leads some manufacturers to favour it on product packaging since it is likely to strike more of a chord of recognition for its healthy benefits.
The new study looked at eliminating the “anti-nutrient compound phytate, resulting in a better absorption of minerals by the human gut” using B. infantis ATCC 15697 and B. pseudocatenulatum ATCC 27919 obtained from the American Type Culture Collection (ATCC).
Results showed that, compared to high-fibre bread baked traditionally, fermentation of the bread with the Bifidobacterium strains led to significantly lower phytic acid levels. Not all phytates were removed however, and residual amounts of myo-inositol triphosphates (InsP3) were recorded. This is important, say the researchers, since InsP3 may positively affect human health.
“It has been shown that strains of the genus Bifidobacterium have phytase activity, suggesting their possible use in the production of bakery products with high level of bran,” wrote the researchers.
“Bran-enriched wheat breads in the presence of the selected human Bifidobacterium strains had technological and sensorial quality similar to the control ones,” they concluded.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, ASAP Article, doi: 10.1021/jf9023678
“Phytate Reduction in Bran-Enriched Bread by Phytase-Producing Bifidobacteria”
Authors: J.M. Sanz-Penella, J.A. Tamayo-Ramos, Y. Sanz, M. Haros
