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Thermal stability and transition temperatures of monovalent salts of high‐acyl gellan gels
Author(s) -
MurilloMartínez María M.,
Tecante Alberto
Publication year - 2015
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12866
Subject(s) - thermogravimetry , rheometry , differential scanning calorimetry , chemistry , thermal stability , potassium , thermal analysis , sodium , nuclear chemistry , analytical chemistry (journal) , inorganic chemistry , chromatography , organic chemistry , thermal , polymer , thermodynamics , physics
Summary Thermogravimetry/derivative thermogravimetry ( TG / DTG ), rheometry and differential scanning calorimetry ( DSC ) were used to study the thermal stability and determine the transition temperatures of the sodium and potassium salts of high‐acyl gellan ( HAG ) in the presence of 0–100 m m NaCl and KCl, respectively. TG / DTG revealed the potassium gellan ( KHAG ) gels to be more stable than those of sodium gellan (Na HAG ), regardless of external cation concentration. Rheometry and DSC showed the melting (T m ) and gelling (T g ) temperatures to increase with cation concentration. The DSC peak temperatures showed thermal hysteresis contrary to rheometry. In most cases, DSC revealed KHAG to exhibit higher T m and T g than Na HAG . Consequently, thermal characteristics of Na HAG and KHAG gels depend on the size of the external cation and its ability to coordinate water molecules. Cation salts of HAG exhibit significantly lower transition temperatures than the commercial preparation from which they were produced.