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Determination of tyrosine by a modified Millon's reaction and its application to potato tuber extracts
Author(s) -
Samotus Boguslaw,
Leja Maria,
Scigalski Andrzej,
Dulinski Jerzy,
Siwanowicz Robert
Publication year - 1982
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740330706
Subject(s) - chemistry , sodium carbonate , sodium acetate , sodium nitrite , tyrosine , chromophore , nitrite , sodium , carbonate , cultivar , chromatography , nuclear chemistry , organic chemistry , botany , biochemistry , biology , nitrate
Abstract A method for determining tyrosine by a modified Millon's reaction and suitable for applying to potato tuber extracts is presented. The deproteinised extract is first treated with a high concentration of mercuric acetate and sodium carbonate. The complex of tyrosine formed with basic mercuric carbonate is then dissolved in sulphuric acid and the intensity of the colour determined photometrically after the formation of Millon's chromophores with sodium nitrite. High concentrations of mercuric and hydrogen ions were necessary in the preliminary purification to minimise their influence on the colour intensity after addition of sodium nitrite. Because of its simplicity the method can be used routinely for large number of samples and will be of use to potato breeders when examining new cultivars.