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TEXTURE PROPERTIES OF GELLAN GELS AS AFFECTED BY TEMPERATURE
Author(s) -
MAO RUNSHENG,
TANG JUMING,
SWANSON BARRY G.
Publication year - 1999
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/j.1745-4603.1999.tb00228.x
Subject(s) - gelatin , materials science , gellan gum , enthalpy , elastic modulus , elasticity (physics) , chemical engineering , composite material , chemistry , thermodynamics , organic chemistry , physics , food science , engineering
Gellan gels can be made very brittle, similar to agar gels, or very flexible, like gelatin gels. The entropy or enthalpy nature governing those gellan gel behaviors was studied by mechanical testing at temperatures varying from 2 to 62C. Both failure stress and strain for 1% low acyl and low acyl/high acyl mixed gellan gels decreased with increasing temperature, indicating that the hydrogen bonding contributed significantly to the stabilization of gellan gels in addition to the polyanion‐calcium‐polyanion bonding. Hydrophobic interactions were less important. The initial Young's modulus for two mixed high and low acyl gellan gels containing 2 mM Ca ++ increased with temperature from 2–42C, indicating entropy elasticity. Average molecular weight between adjacent crosslinks for these two mixed gels was larger than 10 4 . For other gels, the entropy elasticity was not a dominant mechanism for elastic force because of molecular weights between crosslinks and from the observation of negative temperature dependence of the modulus.