Stability of fat globules in UHT milk during proteolysis by the AprX protease from Pseudomonas fluorescens and by plasmin

Chunyue Zhang, Etske Bijl, Karinska Eunike Muis, Kasper Hettinga*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Fat separation is a limiting factor for the shelf life of UHT milk. It may be promoted by the proteolysis of fat surface-adsorbed proteins (FSAP) by proteases that remain active after UHT treatment. The aim of this research was to explore the relationship between the proteolysis of FSAP and fat destabilization. In this study, we developed a full-fat UHT milk-based model system and added either the major bacterial protease AprX from Pseudomonas fluorescens or the major native milk protease plasmin at high levels to induce fast destabilization of the milk fat globules. We monitored changes in physical properties and FSAP composition, and structural changes in fat globules, over 24 h. Our results showed that AprX-induced sedimentation as a result of the flocculation of fat globules, and plasmin induced cream to float as a result of the coalescence of fat globules. This study confirmed that AprX and plasmin can both lead to fat destabilization in full-fat UHT milk, and it provides insights in the underlying mechanisms.

Original languageEnglish
Pages (from-to)179-190
JournalJournal of Dairy Science
Volume103
Issue number1
Early online date14 Nov 2019
DOIs
Publication statusPublished - Jan 2020

Fingerprint

UHT milk
Pseudomonas fluorescens
plasmin
fat globules
Fibrinolysin
proteolysis
Proteolysis
Milk
Peptide Hydrolases
proteinases
Fats
lipids
surface proteins
Membrane Proteins
UHT treatment
flocculation
protein composition
cream
Flocculation
milk fat

Keywords

  • AprX
  • fat stability
  • plasmin
  • proteolysis
  • UHT milk

Cite this

@article{a18e95c369804cca93e90793ed7b68a0,
title = "Stability of fat globules in UHT milk during proteolysis by the AprX protease from Pseudomonas fluorescens and by plasmin",
abstract = "Fat separation is a limiting factor for the shelf life of UHT milk. It may be promoted by the proteolysis of fat surface-adsorbed proteins (FSAP) by proteases that remain active after UHT treatment. The aim of this research was to explore the relationship between the proteolysis of FSAP and fat destabilization. In this study, we developed a full-fat UHT milk-based model system and added either the major bacterial protease AprX from Pseudomonas fluorescens or the major native milk protease plasmin at high levels to induce fast destabilization of the milk fat globules. We monitored changes in physical properties and FSAP composition, and structural changes in fat globules, over 24 h. Our results showed that AprX-induced sedimentation as a result of the flocculation of fat globules, and plasmin induced cream to float as a result of the coalescence of fat globules. This study confirmed that AprX and plasmin can both lead to fat destabilization in full-fat UHT milk, and it provides insights in the underlying mechanisms.",
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author = "Chunyue Zhang and Etske Bijl and Muis, {Karinska Eunike} and Kasper Hettinga",
year = "2020",
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doi = "10.3168/jds.2019-17150",
language = "English",
volume = "103",
pages = "179--190",
journal = "Journal of Dairy Science",
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publisher = "American Dairy Science Association",
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Stability of fat globules in UHT milk during proteolysis by the AprX protease from Pseudomonas fluorescens and by plasmin. / Zhang, Chunyue; Bijl, Etske; Muis, Karinska Eunike; Hettinga, Kasper.

In: Journal of Dairy Science, Vol. 103, No. 1, 01.2020, p. 179-190.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Stability of fat globules in UHT milk during proteolysis by the AprX protease from Pseudomonas fluorescens and by plasmin

AU - Zhang, Chunyue

AU - Bijl, Etske

AU - Muis, Karinska Eunike

AU - Hettinga, Kasper

PY - 2020/1

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N2 - Fat separation is a limiting factor for the shelf life of UHT milk. It may be promoted by the proteolysis of fat surface-adsorbed proteins (FSAP) by proteases that remain active after UHT treatment. The aim of this research was to explore the relationship between the proteolysis of FSAP and fat destabilization. In this study, we developed a full-fat UHT milk-based model system and added either the major bacterial protease AprX from Pseudomonas fluorescens or the major native milk protease plasmin at high levels to induce fast destabilization of the milk fat globules. We monitored changes in physical properties and FSAP composition, and structural changes in fat globules, over 24 h. Our results showed that AprX-induced sedimentation as a result of the flocculation of fat globules, and plasmin induced cream to float as a result of the coalescence of fat globules. This study confirmed that AprX and plasmin can both lead to fat destabilization in full-fat UHT milk, and it provides insights in the underlying mechanisms.

AB - Fat separation is a limiting factor for the shelf life of UHT milk. It may be promoted by the proteolysis of fat surface-adsorbed proteins (FSAP) by proteases that remain active after UHT treatment. The aim of this research was to explore the relationship between the proteolysis of FSAP and fat destabilization. In this study, we developed a full-fat UHT milk-based model system and added either the major bacterial protease AprX from Pseudomonas fluorescens or the major native milk protease plasmin at high levels to induce fast destabilization of the milk fat globules. We monitored changes in physical properties and FSAP composition, and structural changes in fat globules, over 24 h. Our results showed that AprX-induced sedimentation as a result of the flocculation of fat globules, and plasmin induced cream to float as a result of the coalescence of fat globules. This study confirmed that AprX and plasmin can both lead to fat destabilization in full-fat UHT milk, and it provides insights in the underlying mechanisms.

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