Enzymatic test for detecting cows milk in goats milk - based on reaction of xanthine and a tetrazolium salt

摘要

The test is based on colorimetric evidence of xanthine oxidase, the concn. of which in goats milk is about a hundred times less than that in cows milk. The pref. test is based on reaction of xanthine and a tetrazolum salt in the presence of the enzyme resulting in reduction of the salt to a srongly coloured formazan cpd. together with uric acid. The method is fast (about 15 mins.), cheap and does not require special equipment unlike previously proposed methods. Specified salts are 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolum bromide and 3,3'-(3,3'-dimethoxy-4,4'-biphenylylene))-bis-(2-p-nitrophenyl)-5- -phenyl-2H) tetrazolium chloride, the latter being pref. used in the presence of phenazine methosulphate as reaction reinforcing agent.