African Journal of
Food Science

  • Abbreviation: Afr. J. Food Sci.
  • Language: English
  • ISSN: 1996-0794
  • DOI: 10.5897/AJFS
  • Start Year: 2007
  • Published Articles: 978

Full Length Research Paper

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

Lucy M. Chove*
  • Lucy M. Chove*
  • Department of Food Science and Technology, Sokoine University of Agriculture, P.O. Box 3006, Morogoro, Tanzania.
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Alistair S. Grandison
  • Alistair S. Grandison
  • Department of Food and Nutrition Sciences, University of Reading, P.O. Box 226, Reading RG6 6AP, UK.
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Michael J. Lewis
  • Michael J. Lewis
  • Department of Food and Nutrition Sciences, University of Reading, P.O. Box 226, Reading RG6 6AP, UK.
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Abdulsudi Issa- Zacharia
  • Abdulsudi Issa- Zacharia
  • Department of Food Science and Technology, Sokoine University of Agriculture, P.O. Box 3006, Morogoro, Tanzania.
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  •  Received: 20 September 2013
  •  Accepted: 27 January 2014
  •  Published: 28 February 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.