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Plasmin activity as a possible cause for age gelation in UHT milk produced by direct steam infusion

Rauh, Valentin M.; Sundgren, Anja; Bakman, Mette; Ipsen, Richard; Paulsson, Marie LU ; Larsen, Lotte B. and Hammershoj, Marianne (2014) In International Dairy Journal 38(2). p.199-207
Abstract
The effect of enzymatic activity in direct steam infusion heat treated milk with ultra-short holding times (>150 degrees C for <0.2 s) on age gelation during storage was investigated. Preheating at either 72 or 95 degrees C for 180 s was performed. Milk pre-heated at 72 degrees C showed extensive proteolysis and exhibited bitter off flavour and contained <40% intact alpha(s)- and beta-caseins after 6 weeks storage at 20 degrees C. No proteolysis of kappa-casein was detected. Plasmin was identified as active protease and activation of plasminogen was observed as an increase in the rate of casein hydrolysis. Proteolysis in the stored samples correlated with a decrease in pH and with changes in colour. Gelation occurred after 10... (More)
The effect of enzymatic activity in direct steam infusion heat treated milk with ultra-short holding times (>150 degrees C for <0.2 s) on age gelation during storage was investigated. Preheating at either 72 or 95 degrees C for 180 s was performed. Milk pre-heated at 72 degrees C showed extensive proteolysis and exhibited bitter off flavour and contained <40% intact alpha(s)- and beta-caseins after 6 weeks storage at 20 degrees C. No proteolysis of kappa-casein was detected. Plasmin was identified as active protease and activation of plasminogen was observed as an increase in the rate of casein hydrolysis. Proteolysis in the stored samples correlated with a decrease in pH and with changes in colour. Gelation occurred after 10 weeks along with an increase in viscosity and extensive proteolysis of alpha(s)- and beta-caseins. In conclusion, plasmin activity was involved in age gelation and bitterness caused by proteolysis was the shelf-life limiting factor. (C) 2014 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
International Dairy Journal
volume
38
issue
2
pages
199 - 207
publisher
Elsevier
external identifiers
  • wos:000340332000019
  • scopus:84951909495
ISSN
0958-6946
DOI
10.1016/j.idairyj.2013.12.007
language
English
LU publication?
yes
id
d86a855e-147d-4f77-938b-01d54e970364 (old id 4656092)
date added to LUP
2014-09-24 13:19:11
date last changed
2017-08-27 04:39:44
@article{d86a855e-147d-4f77-938b-01d54e970364,
  abstract     = {The effect of enzymatic activity in direct steam infusion heat treated milk with ultra-short holding times (&gt;150 degrees C for &lt;0.2 s) on age gelation during storage was investigated. Preheating at either 72 or 95 degrees C for 180 s was performed. Milk pre-heated at 72 degrees C showed extensive proteolysis and exhibited bitter off flavour and contained &lt;40% intact alpha(s)- and beta-caseins after 6 weeks storage at 20 degrees C. No proteolysis of kappa-casein was detected. Plasmin was identified as active protease and activation of plasminogen was observed as an increase in the rate of casein hydrolysis. Proteolysis in the stored samples correlated with a decrease in pH and with changes in colour. Gelation occurred after 10 weeks along with an increase in viscosity and extensive proteolysis of alpha(s)- and beta-caseins. In conclusion, plasmin activity was involved in age gelation and bitterness caused by proteolysis was the shelf-life limiting factor. (C) 2014 Elsevier Ltd. All rights reserved.},
  author       = {Rauh, Valentin M. and Sundgren, Anja and Bakman, Mette and Ipsen, Richard and Paulsson, Marie and Larsen, Lotte B. and Hammershoj, Marianne},
  issn         = {0958-6946},
  language     = {eng},
  number       = {2},
  pages        = {199--207},
  publisher    = {Elsevier},
  series       = {International Dairy Journal},
  title        = {Plasmin activity as a possible cause for age gelation in UHT milk produced by direct steam infusion},
  url          = {http://dx.doi.org/10.1016/j.idairyj.2013.12.007},
  volume       = {38},
  year         = {2014},
}