Thermal processing of food materials in a single-screw extrude

A. H. Abib, Y. Jaluria, R. V. Chiruvella

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


A numerical simulation of the extrusion cooking of food materials such as low moisture corn starch, in a single screw extruder is carried out. An effort is made to quantify the degree of conversion, or gelatinization, along the screw channel and, in particular, that of the final product at the die. The mathematical model is based on the transport equations for mass, momentum, and energy, along with equations for chemical kinetics for conversion of the material. The materials considered are non-Newtonian with strongly temperature and moisture dependent viscosity. The conversion process is studied only in the heated, rheological fluid region where the thermally controlled reaction rate is well characterized as a zeroth order reaction rate. The temperature and velocity fields are also computed in this region to indicate the nature of the underlying transport processes. The location where the solid food material converts into a fluid with a continuum viscosity behavior is obtained from the model and compared with the available experimental data, indicating a fair agreement. The temperature and velocity variation in the extruder also follow the expected trends. It is observed that most of conversion occurs in the heated region over the last few turns of the screw. Furthermore, the results show that the degree of conversion depends on the length of the solid conveying zone and the transition region. Therefore, an accurate model for these regions is crucial in the quantification of the conversion process to the final product with the desired qualities.

Original languageEnglish (US)
Title of host publicationHeat Transfer in Food Processing
PublisherPubl by ASME
Number of pages11
ISBN (Print)0791811670
Publication statusPublished - Jan 1 1993
Event29th National Heat Transfer Conference - Atlanta, GA, USA
Duration: Aug 8 1993Aug 11 1993

Publication series

NameAmerican Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD
ISSN (Print)0272-5673


Other29th National Heat Transfer Conference
CityAtlanta, GA, USA


All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

Cite this

Abib, A. H., Jaluria, Y., & Chiruvella, R. V. (1993). Thermal processing of food materials in a single-screw extrude. In Heat Transfer in Food Processing (pp. 57-67). (American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD; Vol. 254). Publ by ASME.