Effects of pH-modification on the rennet coagulation of concentrated casein micelles suspensions

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The aggregation of a mixed suspension of native and pre-acidified casein micelles was observed using rheology. Pre-acidified micelles were prepared by addition of glucono-delta-lactone, once pH of 6 or 5.5 was reached, the suspension was concentrated and added to untreated skim milk. Gelation was followed by addition of chymosin, for mixes before or after re-equilibration to the original milk pH. When pre-concentrated micelles were acidified, an earlier gelation point was shown, as well as a higher elastic modulus, compared to control suspensions. When skim milk containing pre-acidified micelles was re-equilibrated to the original pH no gelation was observed after addition of chymosin, in spite of very similar levels of diffusible calcium and phosphate concentration to those of the original milk. It was concluded that it may be possible to fine tune the rheological properties of the final chymosin induced gel network, by pretreating only a portion of the casein micelles, and modifying their colloidal calcium phosphate and the ratio of soluble to micellar casein.

Original languageEnglish
Article number126199
JournalFood Chemistry
Volume316
Pages (from-to)1-6
Number of pages6
ISSN0308-8146
DOIs
Publication statusPublished - 30 Jun 2020

Bibliographical note

Copyright © 2020 Elsevier Ltd. All rights reserved.

    Research areas

  • Calcium phosphate, Concentration, Modified casein micelles, Rennet gelation, Rheology

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