Authors: Gaëlle Roudaut Fabienne Poirier Denise Simatos Martine Le Meste
Publish Date: 2004/06/25
Volume: 44, Issue: 1, Pages: 104-111
Abstract
The uptake of water by low moisture cereal products can have detrimental effects on their texture and cause loss of quality Following the interest in developing techniques suitable for determining texture properties there has also been a move towards identifying the origins of the observed changes Although the origins of the hydration effects are not fully understood dynamic rheology is believed to be a suitable technique for characterising mechanical properties and for identifying the origins of the features observed after moisture pickup In a previous paper the sensory crispness of white bread and of extruded flat bread were correlated with tanδ through the increase in tanδ resulting from the increased hydration associated with loss of crispness The present work shows that such a correlation does not exist with extruded starchsugar samples This means that tanδ data cannot be used to predict fracture properties like those “covered” by crispness The information revealed by the results did however address various questions about the significance of tanδ Indeed the increase in tanδ with increasing hydration was shown to be particularly acute when the starch was mixed with sugar sucrose or fructose In order to interpret these results several hypotheses have been suggested including increased heterogeneity of the systems and sensitivity of tanδ to solute mobility or to localised motions of the matrix
Keywords: