High level of bran negatively impacts dough, bread quality.

Consumption of whole grains and dietary fiber has been associated with a lower risk of cardiovascular disease. Various studies have suggested that fiber may lower serum cholesterol levels and inhibit lipid peroxidation--the oxidative degradation of lipids.

The objective of Turkish scientists was to investigate the effects of different cereal brans on dough and bread properties. In experiments, wheat bran and rice bran were added at 10%, 15% and 20% levels to two different commercial wheat flours. Baking tests were carried out with and without a commercial baking improver composed of soy flour, ascorbic acid, amylase, hemicellulase and sodium stearoyl-2-lactylate (SSL).

The researchers found that the water absorption values of the flours increased in proportion with the amount of wheat bran in the flours. They decreased inversely with the rice bran content. The maximum resistance to the extension and extensibility values of the doughs and the loaf volumes declined with the addition of rice and wheat bran. Specific volume ratios decreased as the amount of bran increased in the formulations. The amount of bran used also determined the moisture content of bread samples.

In sensory testing, panelists found the texture and taste properties to be different between the control and the bran-added breads. Although the product color and aroma improved as rice and wheat bran content increased, high levels of brans caused the crust to brown and the crumb to become very firm.

In addition, other defects in quality, such as low bread volume, a bran-like taste, firmness, browning of the crumb and crumb separation from the crust occurred when bran levels reached 20%. Undesired quality changes also occurred with the addition of bran at the 15% level. But these could be reduced by adding bread improvers. However, the presence of bread improvers did not overcome those quality defects in bread containing a bran content of 20%.

Further information. M. Hikmet Boyacioglu, Food Engineering Department, Istanbul Technical University, Ayazaga Campus, 34469, Maslak Istanbul, Turkey; phone: +90 212 285 6035; fax: +90 212 285 2925; email: mhboyaci@itu.edu.tr.