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Proteolysis during fermentation‐like incubation of cocoa seeds
Author(s) -
Biehl Bole,
Passern Detlef
Publication year - 1982
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.2740331215
Subject(s) - incubation , proteolysis , acetic acid , citric acid , incubation period , chemistry , fermentation , cotyledon , food science , biochemistry , biology , botany , enzyme
Proteolysis in cocoa seeds was studied by fermentation‐like anaerobic incubation to determine whether post‐mortem proteolysis depends only on temperature and acidity. In acetone dry powder incubation, autolytic release of α‐amino nitrogen is optimal at pH 4.0‐4.5 and is higher at 55°C than at 45°C. Proteolysis increases with acidification. However, in seed and seed fragment incubation, acetic acid is more effective than citric acid under similar conditions. Further, a first incubation at a low temperature (40°C) in contrast to a high temperature (50°C) favours post‐mortem proteolysis during a subsequent incubation of cotyledon tissue at 50°C in an acetic solution, whereas it does not with cotyledon dry powder in the same solution. This effect of pre‐incubation temperature in seeds is diminished in the presence of a high concentration of acetic acid. It does not depend on microorganisms, on exudation or on interaction of proteins and polyhydroxyphenols. Since increased proteolysis after incubation at 40°C correlates with structural changes in protein vacuoles and with water uptake by the intact seeds, a causal relationship is indicated.