The demand for functional products is increasing, driven largely by the market interest in foods suitable for improving the health and well-being of consumers. In this regard, diets rich in dietary fibre (DF) are more and more recommended, as it is widely accepted that non-starch polysaccharides (NSP) are associated with the prevention of cardiovascular diseases, the regulation of intestinal function, the promotion of gut health and the protection against colon cancer.
However, the long chains in NSP molecules interfere with the development of a regular and strong gluten network, resulting in a worsening of the rheological properties and handling of bread dough, giving loaf with low volume, hard crumb, bitter flavour and dark colour. The negative effect of fibre on bread texture and consumer acceptability is greatly dependant on the type and components, level of substitution and particle size of the fibre.
Italian Researchers from University of Milan have investigated the modifications induced by enzymatic treatment of fibre on the rheological properties of fibre-enriched bread dough. They used oat bran containing 15% beta-glucans and the enzymatic hydrolysis was done using a commercial food grade cellulolytic and glycosidic enzyme mixture.
The pre-treatment of fibre, therefore, should be considered by millers to enhance wheat milling by-products and to increase their range of products. The use of pre-treated fibre would also minimise the problems associated with the direct use of enzymes in bread-making, which needs a scientific approach beyond the knowledge of some bakers, the researchers said.
The results, published on the International Journal of Food Science & Technology, January 2014, suggest that the enzymatic treatment allows to add high level of soluble fibre (>5%) to the flour without worsening the dough properties during both mixing and leavening. The enzymatic pretreatment proposed in this study may be easily applied by milling companies both for the enhancement of wheat milling by-products and for increasing their range of products. From the point of view of the final user, in a production reality as the Italian one, characterised by numerous small bread-making companies where very often experience and tradition matter more than a scientific approach, the use of pretreated flours/ingredients permits to minimise some of the problems associated with the direct use of enzymes in bread-making.
Further studies are currently being carried out to investigate the effect of treated fibre on bread characteristics.
