Extrusion cooking of cereals is a complex process, regarding a wide range of food products (snack-foods, baby-foods, cereals for breakfastandpasta).Inthiswork,ananalysisofvariance(ANOVA)ontheextrusioncookingprocessforcerealsinaco-rotating twin-screwextruderwascarriedout,usingafinite-elementfluiddynamicsimulationmodel,tostudyshearrate,residencetimeand mixingindexinsidetheextruder,varyingtemperature,screwrotationvelocity,flowrateandextrudergeometry. Besides, the significance analysis, carried out in this study, have shown several aspects of the process under investigation: (i) the interdependence between shear rate, screw rotation velocity and screw axis ratio seems very strong; (ii) the significance of the effects on shear rate of the variations of temperature and flow rate appears less meaningful; (iii) the influence on the residence time of the flow rate and screw axis ratio is more meaningful respect to the screw speed and temperature. The numerical simulations have revealed numerous aspects that can be used to improve the extrusion process: the flow temper- aturecanbevariedwithoutmodifyingthegelatinizationofmaterialthatismainlyinfluencedbyscrewrotationvelocityandscrew axis ratio.
Numerical Study of the Extrusion Process in Cereals Production: Part II. Analysis of Variance
LAFORGIA, Domenico;FICARELLA, Antonio;MILANESE, Marco
2006-01-01
Abstract
Extrusion cooking of cereals is a complex process, regarding a wide range of food products (snack-foods, baby-foods, cereals for breakfastandpasta).Inthiswork,ananalysisofvariance(ANOVA)ontheextrusioncookingprocessforcerealsinaco-rotating twin-screwextruderwascarriedout,usingafinite-elementfluiddynamicsimulationmodel,tostudyshearrate,residencetimeand mixingindexinsidetheextruder,varyingtemperature,screwrotationvelocity,flowrateandextrudergeometry. Besides, the significance analysis, carried out in this study, have shown several aspects of the process under investigation: (i) the interdependence between shear rate, screw rotation velocity and screw axis ratio seems very strong; (ii) the significance of the effects on shear rate of the variations of temperature and flow rate appears less meaningful; (iii) the influence on the residence time of the flow rate and screw axis ratio is more meaningful respect to the screw speed and temperature. The numerical simulations have revealed numerous aspects that can be used to improve the extrusion process: the flow temper- aturecanbevariedwithoutmodifyingthegelatinizationofmaterialthatismainlyinfluencedbyscrewrotationvelocityandscrew axis ratio.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
