Relevance of creep and oscillatory tests for understanding how cellulose emulsions function as fat replacers in biscuits

The fats that are mostly employed in biscuit manufacturing contain a high percentage of saturated fatty acids, giving them the solid consistency that is needed for biscuit manufacture. For health reasons, lower levels of saturated fatty acids and elimination of trans fatty acids are desirable. An emulsion of sunflower oil, water and a cellulose ether was employed to replace all the conventional fat in a short dough recipe. The structure of the different doughs was measured by oscillatory and creep rheological tests and the results were related to dough performance during baking. The effect of the methoxyl and hydroxypropyl content of the cellulose was also evaluated. The compliance values during the creep test fitted the Burger model. The doughs containing the cellulose emulsion presented higher deformation than the control doughs. The oscillatory tests revealed that the effect of frequency on the viscoelastic properties was noticeably different in the two types of dough. In the cellulose dough, considerable structural stabilization was observed at lower frequencies due to its greater elastic component compared to the viscous component. In general, the methoxyl and hydroxypropyl levels of the cellulose ether did not exert a significant effect on the dough's rheological properties. (C) 2014 Elsevier Ltd. All rights reserved.