Gel electrophoresis and fluorescamine methods for the detection of proteolysis of milk heated at high temperatures
Loading...
Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
This study describes the effect of high temperature processing of milk and its susceptibility to proteolysis
during storage. Raw milk was subjected to various Temperature-time combinations (110, 120, 130 and
142 ˚C for 2s) to assess its susceptibility to proteolysis by native enzymes during storage at 37 ˚C for 28
days. Raw milk and processed milk at low temperature (85/15 s) were also used as benchmarks for the
native state and mild heat treatment. Gel electrophoresis (for qualitative analysis) and fluorescamine (for
quantitative analysis) methods were used to detect proteolysis in high temperature heated milk caused by
native enzymes. For the fluorescamine method, clarification was achieved by isoelectric precipitation and
precipitation with acid to obtain pH 4.6 and 6% TCA soluble extracts respectively. Non-clarified samples
were used for gel electrophoresis. Both methods confirmed that raw milk and milk processed at 85/15s
were the most proteolysed, indicating that the high temperatures (110, 120, 130 and 142 ˚C for 2s) lowered
proteolysis through inactivation of heat resistant native enzymes possibly plasmin and hence decreased
milk’s susceptibility to spoilage.
Description
Tanzania Journal of Agricultural Sciences 2013, Vol. 12(2) : 1-9
Keywords
Proteolysis, Fluorescamine, Gel electrophoresis, Isoelectric precipitation