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Caustic‐induced gelation of β‐lactoglobulin
Author(s) -
MercadéPrieto Ruben,
Paterson William R.,
Ian Wilson D.
Publication year - 2008
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/j.1365-2621.2007.01643.x
Subject(s) - chemistry , dissolution , monomer , whey protein , kinetics , activation energy , whey protein isolate , covalent bond , percolation (cognitive psychology) , chemical engineering , chromatography , organic chemistry , polymer , physics , quantum mechanics , engineering , neuroscience , biology
Summary The gelation kinetics of β‐lactoglobulin (βLg) solutions has been determined in the alkaline regime over a wide range of protein concentrations, gelling temperatures and gelation pH (pH gel ), set using NaOH. The behaviour is compared with caustic‐induced gelation of whey protein concentrate and the alkaline dissolution of heat‐induced whey gels. The gelation time decreases significantly between neutral conditions and pH gel 9, because of the activation of the free cysteine groups and displacement to the monomeric form, and between pH gel 10 and 11, due to the base denaturation of βLg. Both transitions are associated with a significant decrease in the activation energy of gelation. At pH gel >11.5 the gelation time is observed to increase with pH gel , owing to destruction of interprotein crosslinks. These results are consistent with the recently reported observation that a minimum pH for the dissolution of βLg gels and aggregates exists around 11.6 [ Biomacromolecules 8 (2007) 1162]. This phenomenon has been assigned to the destruction of non‐covalent interactions that would inhibit the final percolation of the gel.