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A Model for Mechanical Degradation of Wheat Starch in a Single‐Screw Extruder
Author(s) -
DAVIDSON V. J.,
PATON D.,
DIOSADY L L,
RUBIN L. J.
Publication year - 1984
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1984.tb10416.x
Subject(s) - plastics extrusion , amylopectin , extrusion , rheology , starch , materials science , shear stress , residence time (fluid dynamics) , shear (geology) , degradation (telecommunications) , composite material , chemistry , food science , computer science , engineering , amylose , telecommunications , geotechnical engineering
The effect of extrusion cooking in a single screw extruder on the molecular weight distribution of wheat starch was correlated to the starch melt rheology. A simple first‐order model has been developed which defines the extent of mechanical degradation of the amylopectin component as a function of nominal shear stress and residence time in the extruder. A limited set of experimental observations were used to test the model. Iso‐shear stress curves were calculated for the experimental range of conditions. The curves can be used, in conjunction with estimates of the residence time, to calculate equivalent processing conditions, and to predict the extent of amylopectin degradation. The model may allow the use of small extruders to determine fundamental process parameters for full scale extrusion.