46 Relationships between rheological properties and ultra-structural characteristics of developed, partially developed, and non-developed wheat doughs.

L. LEE (1), P. K. W. Ng (1), J. H. Whallon (2), and J. F. Steffe (1). (1) Department of Food Science & Human Nutrition and (2) Department of Crop and Soil Sciences, Michigan State University, East Lansing, MI 48824.

Farinography and Mixography are two commonly used procedures for evaluating dough properties. These procedures, however, cannot separate hydration and energy inputs during dough development--both critically important for understanding fundamental rheological properties of dough. A rheometer and laser scanning confocal microscope (LSCM) were used to study the relationships between rheological properties and ultra-structural characteristics of developed (by farinograph), of partially developed (by rheometer with shear or extensional deformation) and of non-developed dough (Campos et al, 1996; Cereal Chem. 73:105) samples of soft wheat flours. Rheological data indicated that developed dough had the highest G* (most elastic), followed by doughs partially developed with extensional and shear deformations, and then non- developed dough. The LSCM Z-sectioning (scanning of different layers of the sample) showed that developed dough had the most protein matrix, and non-developed dough the least protein matrix. Relationships among deformation, dough rheology and protein matrix will be presented.