Cereal Chem 58:27 - 31.  |  VIEW ARTICLE
Polyphenol Oxidase Activities of Hard Red Winter, Soft Red Winter, Hard Red Spring, White Common, Club, and Durum Wheat Cultivars.

W. M. Lamkin, B. S. Miller, S. W. Nelson, D. D. Traylor, and M. S. Lee. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

Measurement of polyphenol oxidase activity was studied as a possible method for the identification of wheat varieties or classes. A simple, rapid procedure employing a Clark polarographic electrode was developed for determining activity of the enzyme in wheat, and conditions (pH, temperature, etc) were determined for measuring its activity on a variety of substrates. Substrates investigated included phenol, L- tyrosine, catechol, caffeic acid, L-dopa, dopamine, gallic acid, pyrogallol, and d-catechin. Thirty wheat cultivars including hard red winter, soft red winter, hard red spring, white common, club, and durum wheats were studied. Different samples of the same cultivar from different growing locations and crop years gave comparable activities. In many cases, differences in polyphenol oxidase activities could be used to distinguish between cultivars. The durum wheats, which had lower activities, could be differentiated from varieties belonging to other classes by polyphenol oxidase activity alone. Lesser differences in activities were noted between the hard red winter and soft red winter wheats, between the hard red winter and hard red spring wheats, and between the white and club wheats.