COLLABORATIVE STUDY ON COLOUR MEASUREMENT OF SUGAR SOLUTION AT pH 7.0 Vs pH 6.4

摘要

The provisional report (Appendix-1) of the collaborative test states as follows:- From the results of the international collaborative test the change of the pH value from 7.0 to 6.4 in method GS9/1/2/3-8 does not result in any improvement of the precision of the method. Therefore the referee does not see any reason for changing the pH value of 7.0 in the official method GS9/ 1/2/3-8, which was agreed years ago for determination of the colour in solution. Because of the long history of colour measurement at pH =7.0 this convention is also linked to limit values given in regulations and standards, e.g. the Codex Alimentarius. Since a modification of the method would lead to a change of the obtained colour values, it would also be necessary to adopt the existing limit values. Any approach to change this detail of the method would surely lead to irritation of the customers; such a step should not be done without an important reason like a significant improvement of the precision data.