A simple rheological model to predict filled fresh pasta failure during heat treatment

The production of filled fresh pasta was studied with particular emphasis to the importance of the rheological properties of the used dough. A model capable of simulating the biaxial extension of the products during pasteurization has been developed to predict the possible occurrence of rupture leading to very poor quality. The deformation and stress field were approximated by means of membrane deformation and a quasi-stationary hypothesis. Two commercial flours (00-grade and semolina) were tested and the viscoelastic rheological behaviour was modelled with a unique relaxation time that was experimentally determined by means of a time cure test at 1 Hz. Rupture was measured by means of a simple laboratory device and the work of deformation was measured to establish the breakage criterion. Simulations of the deformation process occurring during two different heating treatments were done and analyzed in terms of stress, thickness, deformation and deformation work. The results confirmed the capability of the proposed model to predict rupture conditions and were found to be in agreement with what was industrially expected.