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Comparison of methods for analysis of proteolysis by plasmin in milk

  • Lucy M Chove (a1), Alistair S Grandison (a2) and Michael J Lewis (a2)
  • DOI:
  • Published online: 17 March 2011

Sensitive methods that are currently used to monitor proteolysis by plasmin in milk are limited due to their high cost and lack of standardisation for quality assurance in the various dairy laboratories. In this study, four methods, trinitrobenzene sulphonic acid (TNBS), reverse phase high pressure liquid chromatography (RP-HPLC), gel electrophoresis and fluorescamine, were selected to assess their suitability for the detection of proteolysis in milk by plasmin. Commercial UHT milk was incubated with plasmin at 37°C for one week. Clarification was achieved by isoelectric precipitation (pH 4·6 soluble extracts) or 6% (final concentration) trichloroacetic acid (TCA). The pH 4·6 and 6% TCA soluble extracts of milk showed high correlations (R2 > 0·93) by the TNBS, fluorescamine and RP-HPLC methods, confirming increased proteolysis during storage. For gel electrophoresis, extensive proteolysis was confirmed by the disappearance of α- and β-casein bands on the seventh day, which was more evident in the highest plasmin concentration. This was accompanied by the appearance of α- and β-casein proteolysis products with higher intensities than on previous days, implying that more products had been formed as a result of casein breakdown. The fluorescamine method had a lower detection limit compared with the other methods, whereas gel electrophoresis was the best qualitative method for monitoring β-casein proteolysis products. Although HPLC was the most sensitive, the TNBS method is recommended for use in routine laboratory analysis on the basis of its accuracy, reliability and simplicity.

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AT Andrews 1978 The Composition, Structure and Origin of Protease peptone Component 8F of Bovine Milk. European Journal of Biochemistry 90 6771

ED Bastian & RJ Brown 1996 Plasmin in milk and dairy products: an update. International Dairy Journal 6 435457

D Borda , AV Loey , C Smout & M Hendrickx 2004 Mathematical models for combined high pressure and thermal plasmin inactivation kinetics in two model systems. Journal of Dairy Science 87 40424049

JV Castel , M Cervere & R Marco 1979 A convenient micromethod for the assay of primary amines and proteins with fluorescamine. A re-examination of the conditions of reaction. Journal of Analytical Biochemistry 99 379391

GW Chism , XL Huang & JA Marshall 1979 Sensitive assay for proteases in sterile milk. Journal of Dairy Science 62 17981800

A Crudden & AL Kelly 2003 Studies of plasmin activity in whey. International Dairy Journal 13 987993

N Datta & HC Deeth 2001 Age gelation of UHT milk. Food and Bioproduct processing 79 197210

N Datta & HC Deeth 2003 Diagnosing the cause of proteolysis in UHT milk. Lebensmittel-Wissenschaft und -Technologie 36 173182

AL Kelly & PLH Mcsweeney 2003 Indigeneous proteinases in milk. In Advanced Dairy Chemistry Volume 1 Proteins: 3rd edition Part A (Eds P Fox & PLH Mcsweeney ). New York, Kluwer academic/Plenum Publishers pages: 495544

KKH Kwan , S Nakai & BJ Skura 1983 Comparison of four methods for determining protease activity in milk. Journal of Food Science 48 14181421

TX Le , N Datta & HC Deeth 2006 A sensitive HPLC method for measuring bacterial proteolysis and proteinase activity in UHT milk. Food Research International 39 823830

O Mara , C Roupie , YA Duffy & AL Kelly 1998 The Curd-forming Properties of Milk as affected by the action of plasmin. International Dairy Journal 8 807812

RC Mckellar 1981 Development of off-flavour in Ultra-High Temperature and Pasteurised Milk as a function of proteolysis. Journal of Dairy Science 64 21382145

SS Nielsen 2002 Plasmin system: characteristic, roles, and relationships. Journal of Agriculture and Food Chemistry 50 66286634

J Pereda , V Ferragut , M Buffa , B Guamis & AJ Trujillo 2008 Proteolysis of ultra-high pressure homogenised treated milk during refrigerated storage. Food Chemistry 111 696702

C Schwabe 1973 A fluorescent assay for proteolytic enzymes. Analytical Biochemistry 53 484490

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Journal of Dairy Research
  • ISSN: 0022-0299
  • EISSN: 1469-7629
  • URL: /core/journals/journal-of-dairy-research
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