Phosphatase test
The phosphatase test is a method to be able to detect heat treatment of milk and milk products .
An acidic and an alkaline phosphatase are naturally present in milk . If the natural enzyme reactions of the phosphatase can still be detected, then only the following variants can exist:
- Raw milk
- Thermised milk (gentle process)
- heat-treated milk with a raw milk content of at least 0.3%
In the case of heat-treated milk, e.g. B. pasteurized or long-life milk , these enzymes are deactivated.
principle
In an alkaline medium at 37 ° C, the alkaline phosphatase releases phenol from disodium phenyl phosphate. The amount of phenol formed can be determined photometrically after reaction with 2,6-dibromoquinine-1,4-chlorimide ( Gibb's reagent ) .
Individual evidence
- ↑ Reinhard Mattisek, Gabriele Steiner, Markus Fischer: Food Analysis . 4th edition. Springer, Berlin 2010, ISBN 978-3-540-92205-6 , pp. 237 .