International Journal of Dairy Science and Technology Vol. 1 (3), pp. 042-048, November, 2014.© Advanced Scholars Journals 

Full Length Research Paper

Discovery of proteolysis in high temperature treated milk by Reverse phase high performance liquid chromatography (RP-HPLC)

Kate Hopkins

Department of Diary Science and Technology, Open University Milton Keynes, London ,United kingdom^.

E-mail: [email protected]

Accepted 01 October, 2014

Abstract 

Proteolysis of UHT milk during storage is one of the problems affecting the dairy industry worldwide. Native enzymes have been implicated as being the main cause of spoilage of such milk. In the current study, reverse phase high pressure chromatography (RP-HPLC) method was used to detect proteolysis by native enzymes in high temperature heated milk. The aim of this research was to assess susceptibility of milk to proteolysis by native enzymes, after being subjected to various temperature-time processing conditions. Samples of raw and heated milk were clarified prior to analysis. Clarification was carried out to obtain pH 4.6 and 6% TCA soluble extracts, which were injected into RP-HPLC after filtration. This method confirmed that raw milk and milk processed at 85°C /15 s were the most proteolysed, indicating that the high temperatures employed during this study (110, 120, 130 and 142°C for 2s) inactivated the native enzymes. The RP-HPLC method is a useful method for the detection of proteolysis in milk.

Key words: Reverse phase-high performance chromatography (RP-HPLC), proteolysis, milk, plasmin, heat-treatments.