33A-14 |
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K. SMITH and Y. Vodovotz. Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Ct., 110 Parker Food Science Bldg., Columbus, OH 43210-1007 A wide variety of frozen doughs are available to consumers although no existing product contains enough soy protein to meet the health claim for reducing heart disease. The addition of large amounts of soy protein to bread has been limited due to undesirable sensory and textural properties. The objectives of this study were to characterize the effects of freezing on the mechanical properties of bread made from frozen soy and wheat doughs. Soy (49% wet basis) and wheat doughs were prepared and placed in a -10 °C freezer for 2 and 4 weeks. After thawing, the bread was baked and analyzed using a Dynamic Mechanical Analyzer (DMA) fitted with a single cantilever clamp, Instron Universal Testing Machine, and a sensory panel. DMA was used to determine the storage modulus (stiffness) of samples and to characterize phase transitions. Compression tests (40%) were performed using the Instron to determine bread stiffness. A triangle test (sensory) was used to evaluate differences between soy and wheat breads made from fresh and frozen doughs. A major phase transition ~ 0°ÆC was observed in DMA which was mainly attributed to ice melting. Freezing caused a broadening in this phase transition for both wheat and soy bread and shifted the transition to earlier temperatures for the wheat bread. Additionally, breads made from 1 month frozen dough were stiffer than those made from fresh dough. These results correlated well with sensory analysis. Sensory evaluation showed that there were no differences between breads made from fresh and 2 week frozen doughs for soy or wheat. However, differences were reported for breads made from dough frozen for 1 month. Freezing dough for 2 weeks did not have a major impact on the mechanical properties of wheat or soy bread. Therefore, frozen soy dough could be used as an alternative to fresh dough.
Session 33A, Carbohydrate: General
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