P. Linko and M. Milner. Copyright 1960 by the American Association of Cereal Chemists, Inc.
Germination (wet filter paper), dehydrogenase (as indicated by TTC reduction), glutamic and pyruvic acid decarboxylase, alpha-amylase, and protease activities and maltose value, were determined in wheat samples after treatment with gamma radiation at levels of 0.05, 0.1, 0.5, 1.0, and 3.0 megarep. Germination was reduced even by the lowest radiation treatment (0.05 megarep), whereas the TTC test with whole kernels indicated no significant decrease before the 1.0 megarep treatment. Spectrophotometric determination of formazan produced from TTC by ground grains showed a regular but curvilinear decrease in relation to radiation applied, considerable formazan color remaining even in completely nonviable grain treated with 3.0 megarep. These data suggest that at least a part of the reduction of TTC to formazan is caused by irradiation-produced factors; browning reaction products are the most probable. Glutamic and pyruvic acid decarboxylase activities both decreased to about half of the original value in grain treated with 3.0 megarep. Maltose value showed a considerable rise with radiation level due to increased starch susceptibility, whereas alpha-amylase activity was virtually unchanged even after 3.0 megarep. There was similarly no impairment of protease activity.