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A Physicochemical Model for Extrusion of Corn Starch
Author(s) -
GOMEZ M. H.,
AGUILERA J. M.
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.tb13664.x
Subject(s) - extrusion , absorption of water , moisture , starch , expansion ratio , starch gelatinization , food science , water content , materials science , die swell , solubility , scanning electron microscope , corn starch , viscosity , hydrolysis , raw material , chemical engineering , chemistry , composite material , biochemistry , organic chemistry , geotechnical engineering , engineering
Corn starch extruded at 32.9, 29.2, 24.5, 22.5, 15.9 and 14.2% moisture was analyzed for expansion ratio, enzyme susceptibility, water solubility index, water absorption index, degree of gelatinization, paste viscosity and heat of gelatinization. A model system based on the combination of raw, gelatinized and dextrinized starch was used to represent the physicochemical properties of the extrudates. Reducing extrusion moisture content resulted in a progressive change from gelatinized‐like to dextrinized‐like properties. Maximum gelatinization was observed at about 28‐29% moisture. Below 20% moisture, dextrinization becomes predominant during high‐ shear cooking‐extrusion. Scanning electron micrographs also validate the assumptions of the model.