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Modeling of Dough Mixing Profile Under Thermal and Nonthermal Constraint for Evaluation of Breadmaking Quality of Hard Spring Wheat Flour

¹U.S. Department of Agriculture (USDA), Agricultural Research Service, Red River Valley Agricultural Research Center, Cereal Crops Research Unit, Hard Spring and Durum Wheat Quality Laboratory, Fargo, ND. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the USDA. USDA is an equal opportunity provider and employer. ²Corresponding author. Phone: 701-239-1414. Fax: 701-239-1377. E-mail: jae.ohm@ars.usda.gov ³Department of Plant Sciences, North Dakota State University, Fargo, ND.

This research was initiated to investigate associations between flour breadmaking traits and mixing and empirical dough rheological properties under thermal stress. Thirty hard spring wheat flour samples were analyzed by a Mixolab standard procedure. Mixolab profiles were divided into six different stages, and torque measurements of individual stages were modeled by nonlinear curve fitting using a compound of two solution searching procedures, multidimensional unconstrained nonlinear minimization and genetic algorithm. Mixing patterns followed exponential equations. Dough torque patterns under heat constraint, specifically dough thermal weakening and pasting profiles, were described by a sigmoid logistic equation as a function of time. Dough stability during heating appeared important for bread loaf volume increase from significant correlations between bread loaf volume and parameters generated from models of a dough thermal weakening stage. Multivariate continuum regression was employed to calibrate prediction models of baking traits using Mixolab parameters. Coefficients of determination estimated from prediction models and cross-validation were greater than 0.98 for bake water absorption, mixing time, and bread loaf volume, indicating that the Mixolab parameters have a potential to enhance evaluation of flour breadmaking quality.