HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Silverman, G. J. Articles by Kosikowski, F. V. Search for Related Content PubMed Articles by Silverman, G. J. Articles by Kosikowski, F. V.

A Bacterial Enzymatic Method for Determining Tyrosine in Cheese

Department of Dairy Industry, Cornell University, Ithaca, New York

ABSTRACT

A rapid quantitative method, specific for free tyrosine in ripened Cheddar cheese, is presented. In this procedure an active bacterial decarboxylase preparation converts free tyrosine to its amine, tyramine, under suitable conditions. A multiple ether extraction at pH 10.5 quantitatively recovers both the initial free tyramine and any resulting from decarboxylation. Then from a second sample of the same cheese not subject to decarboxylation only the initial free tyramine is recovered. Colorimetric analysis of the amine with Millon's reagent, preferably, or Folin-Ciocalteu's reagent follows, and through the use of suitable formulas the free tyrosine of cheese, total tyrosine liberated from protein during ripening, and free tyramine can be calculated.

Recovery experiments, precautions, and an apparatus designed for the rapid and simultaneous extraction of the tyrosine contents of ten samples of cheese as tyramine are described and discussed.

¹ Present address: General Foods, Central Research Laboratories, Hoboken, N. J.