UHT milk contains multiple forms of αS1-casein that undergo degradative changes during storage
Holland, John W., Gupta, Rajesh, Deeth, Hilton C., & Alewood, Paul F. (2012) UHT milk contains multiple forms of αS1-casein that undergo degradative changes during storage. Food Chemistry, 133(3), pp. 689-696.
Milk proteins are susceptible to chemical changes during processing and storage. We used proteomic tools to analyse bovine αS1-casein in UHT milk. 2-D gels of freshly processed milk αS1-casein was presented as five or more spots due to genetic polymorphism and variable phosphorylation. MS analysis after phosphopeptide enrichment allowed discrimination between phosphorylation states and genetic variants. We identified a new alternatively-spliced isoform with a deletion of exon 17, producing a new C-terminal sequence, K164SQVNSEGLHSYGL177, with a novel phosphorylation site at S174. Storage of UHT milk at elevated temperatures produced additional, more acidic αS1-casein spots on the gels and decreased the resolution of minor forms. MS analysis indicated that non-enzymatic deamidation and loss of the N-terminal dipeptide were the major contributors to the changing spot pattern. These results highlight the important role of storage temperature in the stability of milk proteins and the utility of proteomic techniques for analysis of proteins in food.
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|Item Type:||Journal Article|
|Keywords:||Milk proteomics, UHT milk, mass spectrometry, 2D Gel Electrophoresis|
|Subjects:||Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > BIOCHEMISTRY AND CELL BIOLOGY (060100) > Proteomics and Intermolecular Interactions (excl. Medical Proteomics) (060109)|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
|Deposited On:||19 Jun 2012 22:44|
|Last Modified:||10 Oct 2012 02:12|
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