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A. LODI and Y. Vodovotz. Dept. of Food Science and Technology, Ohio State Univ., 2015 Fyffe Ct., 110 Parker Food Science Bldg., Columbus, OH 43210-1007 Addition of soy ingredients to a typical wheat bread formulation has been shown to affect the physico-chemical properties and staling rate of the product. Water mobility, in particular, may be strongly influenced by the presence of soy in the system. Magnetic resonance imaging (MRI) allows evaluating water (proton) mobility and spatial distribution in food samples in a non destructive fashion. The objective of this study was to analyze changes in both the average relaxation times and in T2 distribution changes in wheat and soy-containing (60% of the wheat flour replaced with soy ingredients) breads during storage. Both the samples were sealed in polymeric pouches and kept stored at about 4°C for up to ten days. Collection of the experimental data was performed at room temperature using a 4.7T magnet equipped with a 7cm (diameter) coil and controlled by a Bruker Avance Console. Relaxation times, T1 and T2, have been measured and maps (images) of T2 values throughout the samples were constructed. For both the products, relaxation curves were best fitted with a single exponential for T2 and a double exponential for T1. Average T1 and T2 values decreased during storage in wheat bread while remained virtually unchanged in soy bread. Maps of T2 throughout the slices of bread showed a wider distribution of T2 values in wheat bread with higher values of T2 concentrated towards the center of the slice of the fresh product. During storage a higher uniformity of T2 values and a decrease of the average value were developed. These results confirm that proton (water) interaction with macromolecules differ significantly between the soy modified system and the soy-free product and therefore may explain the observed physico-chemical differences.
Session 32, Food Chemistry: Component interactions and processing effects
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |