Spanish team flags up 'right' formulation for functional bread

25 February 2011 (25/02/2011) reported on the findings of a Spanish study published in Journal of the Science of Food and Agriculture, which found that a blend of oat, rye, and buckwheat flours with wheat flour ensures a bread with added value in terms of nutrition, palatability, shelf life and ease of handling during processing, when compared to bread from whole grain flours.

Scientific evidence shows that regular consumption of cereal-based foods provides health benefits and may help regulate blood glucose levels and manage obesity and lowers risk of mortality from cardiovascular disease. Due to this evidence the researchers suggested that breads containing whole grain, multigrain or other functional ingredients are becoming more important in the bakery industry.Crops such as buckwheat, oat, barley, spelt, rye, quinoa and amaranth constitute highly nutritional grain ingredients for healthy food production and special dietary uses. The researchers said they aimed to explore the suitability of cereals and pseudocereals other than common wheat (oat, Kamut, spelt, rye, buckwheat) to be included in mixed matrices with wheat to produce baked goods that meet functional and sensory standards.

Their investigation involved the analysis of single and multigrain flours in doughs and breads in terms of nutritional added value, palatability, shelf and handling during processing.

The researchers assessed the suitability of minor/ancient cereals (rye, oat, Kamut wheat, spelt wheat) and pseudocereals (buckwheat), purchased from the spanish market, in single (100 per cent of wheat flour replacement) and multigrain matrices.

Bread dough consisted of fermented sponge, flour, water and salt. Sponge was prepared by mixing ingredients (50 per cent flour, 50 per cent water, 2 per cent commercial compressed yeast, flour basis) and fermented for 2 hours at 28°C, overnight at 5°C and 1.5 hours at 28°C before being added to the remaining ingredients (50 per cent flour, 50 per cent water, 1.5 per cent salt, flour basis) to make dough of a consistency of 500 BU.

They added that fermented doughs were obtained after bulk fermentation of 10 minutes, dividing (100 g of dough), moulding and proofing up to maximum volume increment (1 hour) and were baked at 170°C for 20 minutes to make bread.For the preparation of multigrain breads, wheat flour was partially replaced with single minor cereals and pseudocereals to make quaternary grain flour blends, said the team. And they explained that for common wheat flour replacement purposes a high-grade refined wheat flour was used to keep the viscoelasticity and gas retention ability of the basic wheat dough matrix as high as possible in order to avoid the diluting effect of bran on gluten strength in wholemeal wheat flours.

The researchers said that viscometric profile, dynamic and static rheological behaviour, crumb hardness and grain, sensory scores, antiradical activity and nutritional factors were measured to quantify significant differences among samples and to test the potential dietary added value of several minor grains.

In terms of single grain use in dough and bread from a nutritional and quality characteristic perspective, the team noted that oat and rye hydrated flours showed the best and the worst pasting and gelling characteristics respectively, while Kamut and spelt doughs achieved mechanical and fundamental rheological properties close to those obtained for wheat. They observed that oat, rye and buckwheat gave breads with enhanced nutritional features (high RS, mineral, bioactive component and dietary fibre contents, low eGI and HI) but tough and closed crumb grain and low ratings by consumers

And the researchers concluded that the mix of oat, rye, buckwheat and common wheat flours (20:20:20:40 w/w/w/w) was the most suitable to make highly nutritious (improved dietary fibre fractions, minerals and antioxidant activity, slower starch hydrolysis), palatable, bread with good shelf life and easy handling during processing.