RELATIONSHIP BETWEEN FIRMING AND WATER MOBILITY IN STARCH-BASED FOOD SYSTEMS DURING STORAGE

Magnetic resonance imaging (MRI) and pulsed nuclear magnetic resonance techniques were used to study the water mobility in sweet rolls durin g storage. Different fractions of water with distinguishable molecular mobility were identified. MRI provided information on the spatial dis tribution of water content and of water mobility. During storage, mois ture migrated from the crumb to the crust, which was associated with t he firming of the crumb. A spatial redistribution of water mobility wi thin the sample was also observed. As storage time increased, the mobi lity of the less mobile water fraction decreased; whereas the mobility of the more mobile water fraction increased upon staling, suggesting a redistribution of water mobility within the water molecules in the s amples. A relationship between water mobility and staling was discusse d.