Protein-fibre combo offers ‘promising’ gluten-free options
Writing in Food Research International, researchers from the University of Milan and Michigan State University state that Psyllium fibre enhanced the physical properties of the dough by forming a film-like structure. Combining this with a continuous protein phase was found to be “critical for the workability of a gluten-free dough”, they said.
“Generally, the more complex experimental formulations (containing corn starch, amaranth flour, pea isolate and Psyllium fibre) investigated in this research looked promising in terms of final bread technological and nutritional quality, even when compared to commercial mixtures already present on the market,” wrote the authors, led by Manuela Mariotti.
The study taps into the growing trend for enhanced gluten-free foods, a rapidly growing market. According to a recent report from Packaged Facts, the gluten-free market has grown at an average annual rate of 28 per cent since 2004, when it was valued at $580m, to reach $1.56bn last year. Packaged Facts estimates that sales will be worth $2.6bn by 2012.
Coeliac disease, a condition characterized by an intolerance to gluten in wheat, is reported to affect up to 1 per cent of children and 1.2 per cent of adults, according to a study in the BMJ’s Gut journal.
Using corn starch, amaranth flour, pea isolate, and Psyllium fibre, Mariotti and her co-workers formulated six types of gluten-free dough, containing different levels of the ingredients: 0 or 40 per cent amaranth flour, 1 or 6 per cent pea isolate, and 0 or 2 per cent Psyllium fibre. Corn starch levels were varied in response to the amounts of the other ingredients used.
In terms of handling and workability, the researchers found that the worst product was, made mainly of corn starch (94 per cent), while replacing 2 per cent corn starch with 2 per cent Psyllium fibre improved both the structure and workability of the dough, “indicating that Psyllium fiber, despite the higher amount of water required to form a dough, could act as an improver of the cohesion of starchy matrix,” said the researchers.
The best performance was observed for the formulations containing all four ingredients: 57 per cent corn starch, 40 per cent amaranth flour, 1 per cent pea isolate, and 2 per cent Psyllium fibre; or 52 per cent corn starch, 40 per cent amaranth flour, 6 per cent pea isolate, and 2 per cent Psyllium fibre.
The researchers also noted that staling of the new formulations would be delayed.
“Psyllium fiber generally enhanced the physical properties of the doughs, due to the film-like structure that it was able to form, and the most complex among the experimental formulations looked promising in terms of final bread technological and nutritional quality even when compared to two different commercial GF mixtures,” concluded the researchers.
Source: Food Research International Published online ahead of print, 7 May 2009, doi: "The role of corn starch, amaranth flour, pea isolate, and Psyllium flour on the rheological properties and the ultrastructure of gluten-free doughs" Authors: M. Mariotti, V.G. Celoria, M. Lucisano, M.A. Pagani, P.K.W. Ng