Changes in Amino Nitrogen, Total Soluble Nitrogen and TCA‐ Soluble Nitrogen Content of Beef as Influenced by Pre‐irradiation Heating, Irradiation Level and Storage at 34° F^a,b

Abstract

Slices of beef were heated to 130", 150" and 195" F, irradiated at 0.1 and 5.0 megarads and stored at 34" F. The effect of these variables on free amino nitrogen, total soluble nitrogen and TCA-soluble nitrogen was determined at 15-day intervals during the 60-day storage period. Increases in heating temperature reduced the rate of release of TSN and TCA-soluble fractions. Amino nitrogen was reduced only at highest temperature employed. Irradiation increased the rate of release of these fractions.The release of amino nitrogen began immediately upon storage of raw beef. Major amounts of TSN were not released until after 15 days storage and TCA-soluble nitrogen not until after 45 days storage. This suggests successive fragmentation of the initially bound protein.

Effect of Pre‐irradiation Heating Temperatures, Irradiation Level, and Storage Time at 34° F on the Free Amino Acid Composition of Beefa,b

“…The rate of proteolysis may be altered by, among other things, heat denaturation of the protein, irradiation, and storage temperature. The changes occurring in amino nitrogen, total soluble nitrogen, and trichloroaceticacid-soluble nitrogen in fresh and irradiated meat stored at 34'F have been reported (Bautista et al:, 1961). The increase was greatest in-the TCA-sol&e fraction, followed by the total soluble and amino nitro- ' Technical Paper No.…”

Post-rigor changes in selected physicochemical properties of myosin B fraction of turkey muscle

“…The activities of several of these enzymes have been determined on various natural and synthetic substrates (Landmann, 1963;Bodwell and Pearson, 1964). Bautista et. al.…”