Effect of the addition of bran fractions on bread properties

High fibre breads were produced adding durum wheat bran fractions of different composition and particle size. Fresh products were characterized for texture, crumb grain, volume, colour, water status (water activity, moisture content, frozen water content, H-1 molecular mobility). The addition of bran fractions with different composition resulted in significantly harder samples with lower volumes as compared to the control (STD), while bran fractions with different particle size did not significantly affect the volume and hardness of the samples (comparable to STD). The addition of bran fractions with different composition and particle size resulted in an altered water status, as shown by crumb moisture content (similar to 43% vs similar to 41% in STD), water activity (0.97 vs 0.96 in STD) and frozen water content (similar to 60-66% vs similar to 51% in STD). H-1 NMR data showed an altered H-1 molecular mobility in bran breads as compared to STD. In particular, an additional H-1 T-2 population was found in the bran samples. This population has been related to the influence of bran on starch-gluten-water interactions.