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AQUEOUS ETHANOL EXTRACTION OF SOYBEAN TRYPSIN INHIBITORS AND CHARACTERIZATION OF A CALCIUM‐SENSITIVE FRACTION
Author(s) -
LIU KESHUN,
MARKAKIS PERICLES
Publication year - 1991
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1991.tb00152.x
Subject(s) - chemistry , ethanol , trypsin , extraction (chemistry) , aqueous solution , chromatography , solvent , fraction (chemistry) , calcium , fermentation , enzyme , biochemistry , organic chemistry
The trypsin inhibition by an 85% aqueous ethanol extract of soybeans was shown to have many similarities to that exhibited by long chain fatty acids and their acyl CoA esters, in terms of concentration dependence, time dependence and susceptibility to Ca ++ suppression. The heat‐stable and hexane‐extractable inhibitor in the extract was thus referred to as the Ca ++ ‐sensitive fraction, in contrast to classic proteinaceous inhibitors. Tempeh fermentation increased the antitryptic activity of the 85% ethanol extract. Extraction of both classic and Ca ++ ‐sensitive inhibitors from soybeans by aqueous ethanol was found to be concentration dependent. Aqueous solvents with less than 20% ethanol removed classic inhibitors as effectively as water, but extracted no Ca ++ ‐sensitive one. Above 20% ethanol in the solvent, the classic inhibitors in the extract decreased until reaching a zero value at 70% ethanol concentration, while the Ca ++ ‐sensitive fraction increased to a maximum at 85%.