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Titre :
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Kinetics of denaturation and aggregation of whey proteins in skim milk heated in an ultra-high temperature (UHT) pilot plant
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Auteurs :
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D. Oldfield ;
H. Singh ;
M. Taylor ;
K. Pearce
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Type de document :
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article/chapitre/communication
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Année de publication :
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1998
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Format :
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p. 311-318
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Langues:
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= Anglais
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Catégories :
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INDUSTRIE AGRO-ALIMENTAIRE
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Mots-clés:
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LAIT ECREME
;
STERILISATION UHT
;
PROTEINE
;
DENATURATION
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Résumé :
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Skim milk was subjected to various temperature-time (70-130°C for 3-1800 s) treatments in a pilot-scale ultra-high temperature (UHT) plant using a direct steam injection (DSI) system. The rates of denaturation and aggregation of beta-lactoglobulin (beta-lg) and alpha-lactalbumin (alpha-la) were determined by quantitative polyacrylamide gel electrophoresis while that of immunoglobulin G (IgG) was determined by affinity chromatography. The order of reaction, the rate constant and the activation energy were determined for the denaturation of beta-lg, alpha-la and IgG using non-linear regression methods. The kinetic parameters obtained for beta-lg and alpha-la showed a marked temperature dependence. Aggregation of beta-lg mainly involved the formation of intermolecular disulphide linkages at all temperatures studied, while the aggregation of alpha-la, particularly below 80°C, appeared to also involve hydrophobic interactions. The kinetic parameters obtained for beta-lg aggregation, due to disulphide bond formation, were similar to those observed for beta-lg denaturation.
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Source :
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International Dairy Journal, vol.8
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