Premium
Extrusion of Cross‐Linked Hydroxypropylated Corn Starches I. Pasting Properties
Author(s) -
McPherson A. E.,
Bailey T. B.,
Jane J.
Publication year - 2000
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cchem.2000.77.3.320
Subject(s) - extrusion , crystallinity , starch , chemistry , differential scanning calorimetry , plastics extrusion , viscosity , rheology , moisture , food science , apparent viscosity , water content , reactive extrusion , rheometry , viscometer , maize starch , corn starch , chemical engineering , composite material , materials science , polymer , organic chemistry , crystallography , thermodynamics , physics , geotechnical engineering , engineering
A series of cross‐linked (0, 0.014, 0.018, 0.024, and 0.028% POCl 3 , dry starch basis) hydroxypropylated (8%) corn starches were extruded using a Leistritz micro‐18 co‐rotating extruder. Process variables included moisture, barrel temperature, and screw design. Differential scanning calorimetry and X‐ray diffraction studies showed the level of starch crystallinity decreased with increasing severity of extrusion conditions. Pasting properties of the extruded starches were examined using a Rapid Visco Analyser. Pasting profiles of starches extruded at different conditions displayed different hot paste viscosity and final viscosity. Increasing starch moisture content during extrusion and level of cross‐linking increased starch viscosity ( P < 0.0001), whereas increasing extrusion temperature and shear decreased starch viscosity ( P < 0.0001). Interactions were found between level of cross‐linking and screw design and between extrusion temperature and starch moisture content ( P < 0.0001).