A sensitive HPLC method for measuring bacterial proteolysis and proteinase activity in UHT milk

• Published in: Food research international Vol. 39; no. 7; pp. 823 - 830
• Main Authors: Le, T.X., Datta, N., Deeth, H.C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2006; Elsevier
• Subjects: Bacteria; bacterial contamination; Bacterial proteinase; Biological and medical sciences; enzyme activity; Fluorescamine; food contamination; Food industries; Fundamental and applied biological sciences. Psychology; HPLC; Milk and cheese industries. Ice creams; peptides; Proteinase activity; proteinases; Proteolysis; psychrotrophic bacteria; reversed-phase high performance liquid chromatography; trichloroacetic acid; UHT milk; Fluorescamine; Proteolysis; Proteinase activity; Bacterial proteinase; HPLC; Peptidases; Enzyme; Dairy product; HPLC chromatography; Hydrolases; UHT milk; Method
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2006.03.008

A sensitive quantitative reversed-phase HPLC method is described for measuring bacterial proteolysis and proteinase activity in UHT milk. The analysis is performed on a TCA filtrate of the milk. The optimum concentration of TCA was found to be 4%; at lower concentrations, non-precipitated protein blocked the HPLC while higher concentrations yielded lower amounts of peptides. The method showed greater sensitivity and reproducibility than a fluorescamine-based method. Quantification of the HPLC method was achieved by use of an external dipeptide standard or a standard proteinase.