The polyphenol content of quinoa and buckwheat flours may enhance the nutritional profile of gluten-free formulations, and may be a better option than amaranth, says a new study.
The findings could lead to enhanced products for the blossoming gluten-free food market, worth almost $1.6bn last year, according to Packaged Facts, and experiencing a compound annual growth rate of 28 per cent over four years.
Sufferers of coeliac disease have to avoid all gluten in their diet, but diagnosis is not the only factor. Other sectors of the population, such as those who have self-diagnosed wheat or gluten intolerance or who believe gluten-free to be a healthier way of eating, are also strong drivers.
But against this backdrop of popularity, there have been concerns that some gluten-free products on the market made with rice, corn and potato flour and xanthan or guar gum to improve texture have sub-optimal levels of essential nutrients.
“Improving the nutritional quality of gluten-free products is essential, as the presently available gluten-free products in the market have been shown to be of poor nutritional quality,” wrote the researchers, led by Eimear Gallagher from the Ashtown Food Research Centre, Teagasc.
According to their results, published in Food Chemistry, bread made from quinoa and buckwheat had significantly higher nutritional content in terms of antioxidants and polyphenol than wheat bread.
“Therefore, these pseudocereal seeds represent feasible ingredients in gluten-free baking for increasing the antioxidant properties and phenolic content of gluten-free breads, and improving their overall nutritional quality,” they stated.
Gallagher and her co-workers examined the polyphenol and antioxidant content of extracts of amaranth, quinoa, and buckwheat, and compared them to wheat. They subsequently investigated how sprouting and baking affected the results.
According to their findings, buckwheat topped the rankings for phenol content, followed by quinoa, then wheat, and finally amaranth. Analysis of using chromatography showed the main pehnols were phenolic acids, catechins, flavanol, flavone and flavonol glycosides.
Baking (breadmaking) of all samples led to a reduction in total phenol content and antioxidant activity, but “all of the breads containing pseudocereals showed significantly higher antioxidant capacity when compared with the gluten-free control”, said the researchers.
The study supports earlier findings from the Celiac Disease Center at Columbia University in New York, which found that replacing standard gluten-free flours with those made from ‘alternative’ grains like oats and quinoa may improve intakes of protein, iron, calcium and fibre, according to researchers
“By adding three servings of gluten-free alternative grains, the nutrients (fiber, thiamine, riboflavin, niacin, folate and iron) are improved,” wrote the researchers, led by Anne Lee, in the Journal of Human Nutrition and Dietetics.
In a review in the journal Trends in Food Science & Technology (2010, Vol. 21, pp 106-113) co-authored by Professor Arendt, it is noted that, despite the successful formulation of gluten-free products using these ‘pseudo-cereals’ “availability of these products in the market is still quite limited. More research is necessary to fully exploit the functionality of these seeds as gluten-free ingredients in the production of palatable products which are also nutritionally balanced,” they added.
Source: Food Chemistry
Volume 119, Issue 2, Pages 770-778
“Polyphenol composition and in vitro antioxidant activity of amaranth, quinoa buckwheat and wheat as affected by sprouting and baking”
Authros: L. Alvarez-Jubete, H. Wijngaard, E.K. Arendt, E. Gallagher