Effect of size reduction on colour, hydration and rheological properties of wheat bran

Abstract

The aim of this study was to determine the effect of size reduction of wheat bran (WB) on water holding capacity (WHC), water retention capacity (WRC), swelling capacity (SC); rheological and colour properties. Coarse WB exhibited the highest mean values for WHC (6.49 g/g), WRC (5.76 g/g), SC (7.67 g/g) and OHC (4.23 g/g), while these values were significantly reduced in fine WB. Size reduction increased lightness of WB as indicated by high L* values (62.65 to 75.80), Hue angle of 74.63 and whiteness index value of 81.42. Increasing WB additions increased water absorption of dough from 63 to 70.2%, while dough stability decreased from 12.5 min to 6.80 min. As coarse WB addition increased from 1 to 15 g extensibility decreased from 419 BU to 283 BU (highest level of addition). A negative correlation (r2 = –0.992) was found between farinograph water absorption and all extensograph indices measured; implying that an increase in water absorption of dough led to a significant decrease in extensibility, maximum resistance and energy recorded for the dough. WB can be used as potential additive in foods like bread/ doughnut with the aim of optimizing their quality parameters such as nutritional and textural properties.