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EFECT OF pH BUFFERS ON MECHANICAL PROPERTIES OF GELLAN GELS
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.tb00208.x
Subject(s) - calcium , distilled water , buffer (optical fiber) , citric acid , chemistry , brittleness , phosphate buffered saline , gellan gum , chromatography , materials science , chemical engineering , composite material , biochemistry , organic chemistry , telecommunications , food science , computer science , engineering
The strength and deformability of calcium cross‐linked gellan gels as affected by pH 3.5 and 5.0 citrate and acetate buffers were measured by large compressive deformation test until failure. The trend of dependence of gel strength on polymer and calcium concentrations was similar to gels formed in distilled water without pH adjustment. A critical calcium concentration was observed for each gellan concentration. Gels formed at the critical calcium concentration exhibited the maximum strength. The chelating effect of pH 5.0 citrate buffer greatly increased the critical calcium concentration. The failure strain, representing the deformability, of gellan gels formed in buffers behaved differently from gels formed in distilled water. In the pH 3.5 buffer systems, gellan gels were brittle regardless of gellan and calcium concentrations. In the pH 5.0 buffer systems, gellan gels were brittle at high calcium concentrations and ductile at calcium concentrations less than 24 mM in citric buffer and less than 6 mM in acetate buffer.