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The effect of temperature and moisture on the mechanical properties of extruded cornstarch
Author(s) -
Ditudompo Srivikorn,
Takhar Pawan S.,
Ganjyal Girish M.,
Hanna Milford A.
Publication year - 2013
Publication title -
journal of texture studies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.593
H-Index - 54
eISSN - 1745-4603
pISSN - 0022-4901
DOI - 10.1111/jtxs.12013
Subject(s) - viscoelasticity , materials science , rheology , extrusion , die swell , creep , moisture , water content , composite material , starch , chemistry , geotechnical engineering , food science , engineering
The viscoelastic properties of extruded cornstarch were measured as a function of process conditions. The extruded cornstarch samples were conditioned in the moisture range of 12.9–31.2% (dry basis). Dynamic and creep behavior of the extrudate were evaluated using a dynamic mechanical analyzer. The storage ( G ′) and loss moduli ( G ″) were determined in the temperature range of 30–100C and oscillation frequency range of 0.1–51 Hz. The G ′ and G ″ values showed an increasing trend with a decrease in temperature and moisture content and an increase in frequency. This implied an increase in solid‐like behavior when the temperature and moisture content were reduced or the frequency was increased. Rheological parameters based on creep behavior were assessed at 30, 60 and 85 C . Creep data, fitted using B urger's model, were highly dependent on both moisture content and temperature. Practical Applications The viscoelastic properties obtained in this experimental research can be used for solving the non‐ F ickian fluid transport model for studying the expansion of starch during extrusion. The viscoelastic properties also provide an indication about the textural characteristics of starch as a function of extrusion conditions.