Conditions and mechanisms leading to covalent aggregation of beta-casein (betaCN) were studied in protein solutions heat treated in the absence or presence of glucose. Under all the tested heating conditions, covalent aggregation of betaCN occurred only in the presence of glucose. Only high-MW aggregates (much greater than 100 kDa) were detectable by polyacrylamide-gel electrophoresis in the presence of SDS, whereas gel permeation chromatography in the presence of urea showed that aggregates with lower MW were formed as well. A characteristic unordered structure was observed using transmission electron microscopy for the covalent aggregates of betaCN obtained in the presence of glucose, in contrast to the mostly spherical ones due to hydrophobic interactions only. In addition, lysinoalanine (LAL), lysylpyrraline (LPA) and pentosidine (PTD), as possible crosslinking molecules in proteins, were quantified by HPLC. The highest amounts of LAL (approximately 150 mmol/mol betaCN) were found in the unglycosylated betaCN, suggesting that this molecule is mainly involved in intra-molecular reactions. Very small amounts of LPA (< 2 micromol/mol betaCN) were found in extensively aggregated betaCN. The behaviour of PTD formation followed that of betaCN aggregation but the low values found (few mmol/mol of protein) suggest that it can only play a minor role. Although the covalent aggregation of betaCN is advanced Maillard reaction dependent, molecules other than those considered here are responsible for intermolecular crosslinking but their nature is presently unknown.

Heat-induced aggregation and covalent linkages in beta-casein model systems / L. Pellegrino, M.A.J.S. van Boekel, H. Gruppen, P. Resmini, M.A. Pagani. - In: INTERNATIONAL DAIRY JOURNAL. - ISSN 0958-6946. - 9:9(1999), pp. 255-260.

Heat-induced aggregation and covalent linkages in beta-casein model systems

L. Pellegrino
Primo
;
P. Resmini
Penultimo
;
M.A. Pagani
Ultimo
1999

Abstract

Conditions and mechanisms leading to covalent aggregation of beta-casein (betaCN) were studied in protein solutions heat treated in the absence or presence of glucose. Under all the tested heating conditions, covalent aggregation of betaCN occurred only in the presence of glucose. Only high-MW aggregates (much greater than 100 kDa) were detectable by polyacrylamide-gel electrophoresis in the presence of SDS, whereas gel permeation chromatography in the presence of urea showed that aggregates with lower MW were formed as well. A characteristic unordered structure was observed using transmission electron microscopy for the covalent aggregates of betaCN obtained in the presence of glucose, in contrast to the mostly spherical ones due to hydrophobic interactions only. In addition, lysinoalanine (LAL), lysylpyrraline (LPA) and pentosidine (PTD), as possible crosslinking molecules in proteins, were quantified by HPLC. The highest amounts of LAL (approximately 150 mmol/mol betaCN) were found in the unglycosylated betaCN, suggesting that this molecule is mainly involved in intra-molecular reactions. Very small amounts of LPA (< 2 micromol/mol betaCN) were found in extensively aggregated betaCN. The behaviour of PTD formation followed that of betaCN aggregation but the low values found (few mmol/mol of protein) suggest that it can only play a minor role. Although the covalent aggregation of betaCN is advanced Maillard reaction dependent, molecules other than those considered here are responsible for intermolecular crosslinking but their nature is presently unknown.
β-Casein aggregation; Maillard reaction; Protein crosslinking
Settore AGR/15 - Scienze e Tecnologie Alimentari
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/199236
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 45
  • ???jsp.display-item.citation.isi??? 36
social impact