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Bound quinic acid as a measure of coupling of leaf and sunflower‐seed proteins with chlorogenic acid congeners: Loss of availability of lysine
Author(s) -
Davies Anthony M. C.,
Newby Vilas K.,
Synge Richard L. M.
Publication year - 1978
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740290106
Subject(s) - chlorogenic acid , sunflower , lysine , browning , autolysis (biology) , food science , chemistry , biochemistry , sunflower seed , polyphenol , avena , amino acid , biology , botany , horticulture , enzyme , antioxidant
Changes were studied in the bulk protein of tobacco leaves, lucerne shoots and sunflower‐seed kernels subjected to aerobic autolysis at room temperature. Bulk‐protein fractions from cigar and from commercial sunflower‐seed meal were also examined. Quinic acid, released by cold alkaline hydrolysis, was used as a measure of binding of chlorogenic acid residues to the proteins. On aerobic autolysis, the proteins of the leafy materials underwent some proteolysis; chlorogenic acid residues became bound to the protein, with concomitant diminution of free chlorogenic acid. The proteins showed browning, increased ultraviolet absorption and diminished content and “chemical availability” of lysine. However, during aerobic autolysis, the bulk protein of sunflower‐seed kernels did not couple appreciably with the chlorogenic acid congeners present; the above accompanying phenomena were also largely absent. It is concluded that, when protein‐rich plant materials are to be fed to monogastric animals, and particularly when their lysine content is critical, more attention should be paid to effects of the polyphenols and polyphenol oxidases present in the original plant.