Bran in Bread: Effects of Particle Size and Level of Wheat and Oat Bran on Mixing, Proving and Baking

Abstract

The effects of adding wheat and oat bran, at different levels and milled to varying particle size ranges, to dough formulations were investigated, with respect to aeration and dough development during mixing, expansion during proving and fi nal baked loaf characteristics. Addition of bran reduced the density of the dough at the end of mixing, largely because of the increased water absorption, with bran particle size having little effect on dough density. Wheat bran substituted for fl our at 7.5% increased the capacity of the doughs to expand during proving, but despite this the baked loaf volumes were lower, and even lower at 15%. Grinding the wheat bran had little effect on optimum work input, water absorption and expansion during proving, but gave slightly lower loaf volumes and a fi ner crumb texture. The low correlation between proving expansion and baked loaf volume suggested that the effects of the wheat bran in bread formulations occurred during baking. By contrast, adding oat bran reduced both the maximum expansion capacity of the dough during proving and the baked loaf volume, suggesting that the oat bran exerted its effects largely during proving. Grinding the oat bran gave lower optimum work inputs and higher water absorptions, and reduced both proving expansion and baked loaf volumes.

Rheological properties of wheat flour dough and French bread enriched with wheat bran

“…To take into account water absorption increase due to bran addition, our expert baker adjusted the amount of water added, at the end of pre-mixing stage in view of dough behaviour and mechanical power measurements, in agreement with the French breadmaking procedure (AFNOR standard V03-716). This led to add an amount of water of about half the level of bran to the control water amount (Campbell et al, 2008).…”

“…As solid particles act like a charge in a suspension, bran addition also increases the extensional and shear viscosities (Cavella et al, 2008;Bonnand-Ducasse et al, 2010), which is unfavourable to the growth of the gas cells. Campbell et al (2008) also suggested that bran acted during baking rather than during proofing by releasing extra water available for starch gelatinisation, and thereby lowering the final bread volume.…”

Dough characteristics of Irish wheat varieties II. Aeration profile and baking quality

“…The remaining samples show similar density profiles, though significant differences were observed between the samples for the minimum dough density and the time at which it occurred. The maximum dough expansion was calculated as 1/minimum dough density (Campbell et al, 2008(Campbell et al, , 2008a(Campbell et al, , 2008b and the results are shown in Fig. 4a.…”

“…They were able to follow the differences in proving patterns resulting from the differences in fat levels and mixing pressure, and concluded that monitoring dough density is a valid and sensitive technique that allows for better investigation of aerated food products. The method was also used successfully to investigate the bran particle size (Campbell, Choy Koh, Man Keung, & Morgenstern, 2008;Campbell, Ross, & Motoi, 2008a), and the effect of oat and wheat bran on the breadmaking process (Campbell, Ross, & Motoi, 2008b).…”

Impact of wheat bran addition on the temperature‐induced state transitions in dough during bread‐baking process

“…The negative effect of wheat bran addition on bread quality has been wellproven in the literature. Bran impacts the dough extensibility, stability and viscosity (Schmiele et al, 2012), which ultimately lead to impaired loaf volume and textural properties (Campbell et al, 2008). Nevertheless, this impact could not be direct as bread dough undergoes various physical changes during baking, governed by the state transitions of its components and redistribution of water within the system.…”