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Degradation of Wheat Starch in a Single‐Screw Extruder: Mechano‐Kinetic Breakdown of Cooked Starch
Author(s) -
DIOSADY L. L.,
PATON D.,
ROSEN N.,
RUBIN L. J.,
ATHANASSOULIAS C.
Publication year - 1985
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.1365-2621.1985.tb10568.x
Subject(s) - viscometer , starch , plastics extrusion , barrel (horology) , degree of polymerization , viscosity , degradation (telecommunications) , materials science , moisture , chemistry , chemical engineering , chromatography , composite material , polymer , food science , polymerization , telecommunications , computer science , engineering
Wheat starch was processed in a 19 mm diameter split‐barrel laboratory extruder under varying conditions of barrel temperature (79–121 o C), screw speed (50, 100 rpm) and moisture content (25, 30%). Final product and samples removed from along the barrel length were examined for changes in molecular size by dilute solution viscometry. Final products were also examined for paste viscosity and estimated degree of cook. A mathematical model was developed which relates the residence time of the starch in the barrel, the nominal shear stress acting on the starch and the degree of cook of the product to the extent of molecular degradation of the starch. Solution viscometry was found to be more rapid than gel permeation methods previously used to determine the extent of molecular changes.