Study of the rheological model of pasta dough for additive manufacturing

Rheological measurements were carried out on pasta dough from a mixture of semolina and whole wheat flour from durum wheat. To determine the rheological characteristics under extrusion conditions and its relation to the behavior of the pasta dough during the processing of products, the object of study was extruded using a capillary viscometer and a laboratory extruder. Creep tests were also carried out to check the possibility of neglecting the elastic component of deformation. The influence of temperature and degree of hydration on the viscosity of pasta dough was investigated. The purpose of this study is to determine the rheological model required for the subsequent analysis of the process of extrusion 3D-printing of pasta dough. The results showed that the pasta dough behaves like a pseudoplastic liquid, which can be described using a power law model. Increased hydration levels reduced the apparent dough viscosity, which correlated with extrusion pressure. Studies have confirmed the viscoelastic behavior of pasta, but an important observation for the purposes of this study is that the elastic component of deformation is very small compared to yield conditions. There was a decrease in the value of the coefficient of consistency with an increase in the degree of hydration of the dough from 30 to 34%. The moisture index of the dough also influenced the flow index. The overall value of the flow index varied from 0.284 for 30% and 0.404 for 34%, it was observed to increase with increasing moisture content. The developed rheological models of pasta dough will be used to simulate the flow behavior when printing in an extrusion-type 3D printer using computational fluid dynamics technology.