Submitted to: Carbohydrate Polymers
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/3/2002
Publication Date: 3/1/2003
Citation: BYARS, J.A., CARRIERE, C.J., INGLETT, G.E. CONSTITUTIVE MODELING OF BETA-GLUCAN/AMYLODEXTRIN BLENDS. CARBOHYDRATE POLYMERS. 2003.v.52(3).p.243-252. Interpretive Summary: An understanding of the flow behavior of materials is important both in their processing and applications. Many equations have been developed to describe the flow behavior of synthetic polymers, but it is not known whether they apply to biopolymers. This work studied the flow properties of Oatrim, a USDA technology that is used as a fat replacer and source of oat fiber. The flow properties were compared to different models, and the strengths and weaknesses of the models were assessed. Although some of the models can be used for biopolymers, this work points out special issues that must be addressed when studying biopolymers. The use of these models can aid in the cost-effective development of new bio-based materials for specific value-added applications. The models are also of use in quality control issues during the production of bio-based materials.
Technical Abstract: Accurate constitutive equations are required for the understanding of many food processes. Although many models have been developed for synthetic polymers, their applicability to food and biopolymer systems has not been established. The purpose of this work was to test the ability of constitutive equations to model the rheological behavior of beta-glucan/amylodextrin blends in a range of flows. The predictions of the K-BKZ, Giesekus, Phan-Thien-Tanner, and Bird-Carreau models were compared to experimental results in steady shear, startup of steady shear, stress relaxation, and biaxial extension flows. The K-BKZ model yielded the most accurate predictions across the range of flows. The Giesekus and Phan-Thien-Tanner models gave good results in shear flows, but failed to predict the correct strain dependence in stress relaxation. The Bird-Carreau model did not capture many features of the flow behavior. The results indicate the need to test thoroughly constitutive equations before using them to model food processes.