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FORMATION OF FREE RADICALS IN DRY MILK PROTEINS
Author(s) -
HANSEN P. M. T.,
HARPER W. J.,
SHARMA K. K.
Publication year - 1970
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1970.tb04820.x
Subject(s) - electron paramagnetic resonance , chemistry , casein , radical , fragmentation (computing) , hyperfine structure , flavor , grinding , spectroscopy , whey protein , crystallography , food science , biochemistry , nuclear magnetic resonance , materials science , biology , metallurgy , ecology , physics , quantum mechanics
SUMMARY The possible formation of free radicals in dry milk proteins by mechanical energy has been studied by electron spin resonance (ESRI spectroscopy. Grinding of various milk proteins with mortar and pestle for 5 min or longer yielded perceptible electron spin resonance signals. The signals did not exhibit characteristics of hyperfine structure and all had g‐values close to that of a free electron (2.001. The intensity of the signals was particularly strong for the sulfhydryl‐containing proteins, β‐lactoglobulin and k‐casein, and increased with grinding time. The signals were considerably reduced by subsequent heating of the dry protein at 100°/10 min. The grinding of whole casein was in ail cases accompanied by the release of a gluey odor, suggesting that the gluey‐flavor defect may be related to protein fragmentation.