Fortification of gluten-free breads with iron and soy flour

SCIARINI L.S; BINAGHI M.J; GRECO C.B; PELLEGRINO N.R; PÉREZ G.T; RONAYNE DE FERRER P.A.

Rosario

Conferencia; Primera Conferencia Latinoamericana ICC; 2007

ICC. International Association for Cereal Science and Technology

Celiac Disease (CD) is characterized by symptoms such as severe malabsorption of nutrients, which results in steatorrhoea, abdominal discomfort, weight loss or gain, tiredness, anemia, and severe diarrhea (Moore et al., 2004). Baking products for celiac patients are of low nutritional and technological quality. Soybean flour has been used in previous studies (Ribotta et al., 2004) to fortify and to improve the mechanical behaviour of gluten-free batters and breads. In Argentina, wheat flour is fortified with iron, folic acid, thiamine, riboflavin and niacin (Ley 25.630). Nevertheless, other cereal and legume flours are not included in this legislation, despite the malabsorption that affects celiac people. The aim of this work was to evaluate the technological quality and iron potential availability of gluten-free breads added with soy flour and fortified with ferrous sulphate, and to compare them with their wheat breads counterparts. Gluten free breads were made of rice and corn flours, and wheat breads were made with non-fortified flour. Breads were supplemented with 10% and 20% of inactive soy flour. Flours or flour blends were fortified with 30 ppm of ferrous sulphate. Quality parameters as bread specific volume (BSV), crust colour and crumb texture were determined, and an image analysis was carried out. To determine iron potential availability, an in vitro digestion was carried out, and total and dialyzable iron were calculated as proposed by Wolfgor et al. (2002). Iron addition did not affect any of these quality parameters, neither soy flour addition affected significantly iron potential availability. On the other hand, soy flour incorporation did affect quality variables: in gluten free breads, it improved BSV, lowered crumb hardness, and crumb structure of these breads was finer. It decreased L and increased a and b values (globally meaning a darkening of the crust). Considering wheat breads, soy flour addition yielded poorer technological quality, decreasing BSV and rising crumb hardness, as well as reducing cell area.  Regarding iron potential availability, wheat breads showed significantly higher values than those of gluten-free breads, probably due to the lower phytic acid content of wheat flour in comparison with rice and corn flours. Considering these results, gluten-free breads are susceptible of being added with soy flour in order to offer a protein matrix to these products and to increase their nutritional value. Besides, it can be fortified with iron, although further studies are required to determine its optimal dose, since corn and rice flours are rich in phytic acid, which lowers iron dialyzability.