ABSTRACT
The analysis of heated products in which the Maillard reaction has developed requires particular precautions. The amino acid determination aims at two different purposes: to determine the total quantity of amino acids contained in a sample and to realize the percentage of their availability. In theory a drastic acid hydrolysis sets free the available and blocked forms of the amino acids with the exception of the destroyed fraction, which cannot be regenerated by this method. Thus, chemists have ascertained that the first stages of the Maillard reaction are reversible; the amino acids which have combined with sugars can be recovered. The measurement of the amino acid fraction that is available for organisms is particularly useful from the nutritional point of view; especially with respect to lysine, which selectively undergoes the detrimental effects of heat treatments. A successful chemical method, which can distinguish the lysine fraction whose e-amino groups are available, utilizes the amino acids reaction with fluoro,2,4,dinitrobenzene.
