Effect of modified celluloses on dough rheology and microstructure

The effect of different modified celluloses on dough microstructure and theological characteristics was studied. Microcrystalline cellulose (MCC), carboxymethylcellulose (CIVIC) and two different types of hydroxypropylmethylcellulose (HPMC F4M and HPMC F50) were tested in a range of concentration from 0.25% to 1.5% (flour basis). Doughs were formulated without and with salt (2%w/w flour basis). Farinographic water absorption increased when hydrocolloids were incorporated and the highest values were obtained in mixtures without NaCl and when HPMCs were added. A linear relationship between the percentage increment in water absorption and the hydrocolloid level was observed within the assayed range of concentrations. The development time was markedly increased when CIVIC was added. CMC and HPMC did affect or not dough stability depending on the presence or absence of salt whereas the stability was not modified by MCC. Texture attributes and the rheometric parameter tan delta were analyzed through Principal Component Analysis (PCA). Two factors described the 88.9% of total variation, one of them composed by hardness, consistency, adhesiveness and tan delta and the other composed by resilience and cohesiveness. Hydrocolloids addition softened the dough, particularly when salt was absent. Samples with salt and with hydrocolloids exhibited more cohesive and less resilient characteristics. Rheological results were in agreement with the characteristics of gluten network studied by SEM since a diminished stability and softer dough could be associated with a more disrupted matrix. (C) 2009 Elsevier Ltd. All rights reserved.