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The Comparative Heat Stability of Bovine β‐Lactoglobulin in Buffer and Complex Media
Author(s) -
Galani Despina,
Apenten Richard K. Owusu
Publication year - 1997
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199705)74:1<89::aid-jsfa773>3.0.co;2-p
Subject(s) - chemistry , thermostability , denaturation (fissile materials) , enthalpy , thermodynamics , whey protein , atmospheric temperature range , kinetic energy , activation energy , thermal stability , buffer (optical fiber) , chromatography , kinetics , analytical chemistry (journal) , organic chemistry , nuclear chemistry , telecommunications , computer science , physics , quantum mechanics , enzyme
The heat stability of β‐lactoglobulin (β‐lg) is usually described with reference to a concentration‐dependent pseudo‐rate constant k . Kinetic and thermodynamic parameters for the irreversible denaturation of β‐lg, in a whey protein mixture dissolved in Tris‐HCl buffer, were examined over a wide temperature range 75–120°C and for degrees of denaturation [( C o ‐ C t )/ C o ] up to about 90%. The first‐order kinetic model best described β‐lg denaturation over the temperature range 75–85°C, whereas the second‐order model applies in the range 90–120°C. A comparison between β‐lg thermostability in buffer and literature data pertaining to more complex heating media (whey and milk), over the range 75–120°C, was carried out on the basis of changes in activation free energy (Δ G # ), which itself takes into account changes in both activation enthalpy (Δ H # ) and activation entropy (Δ S # ). It was found that the thermal stability of β‐lg in different media, and irrespective of the kinetic model assumed in the present study, can be ranked: buffer ≪ whey>milk for the temperature range 75–85°C. On the contrary, at the higher temperature range, 90–120°C, the ranking is buffer