Ellman's reagent for determination of the heat treatment of milk powder. Improved analytical procedure based on a stopped-flow kinetic study.

摘要

The reproducibility and accuracy of the method for determination of heat treatment of dried milk, based on the reaction between Ellman's reagent (5,5'-dithiobis(2-nitrobenzoic acid)) and exposed SH-groups, was improved by salting-out of the proteinby stepwise addition of (NH4)2SO4 and by rigorous pH control. This was done using a 0.10 M borax buffer (pH 9.50) for adjustment of the milk pH to 8.00 while using a standard curve obtained at the same pH.