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EFFECT OF BEAN (Phaseolus vulgaris) ALBUMINS ON PHASEOLIN IN VITRO DIGESTIBILITY, ROLE OF TRYPSIN INHIBITORS
Author(s) -
GENOVESE MARIA INÉS,
LAJOLO FRANCO M.
Publication year - 1996
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.1745-4514.1996.tb00556.x
Subject(s) - trypsin , proteolysis , albumin , phaseolus , casein , biochemistry , chemistry , pepsin , globulin , chymotrypsin , food science , enzyme , biology , botany , immunology
The in vitro digestibility of albumin proteins from Phaseolus vulgaris was low (26–32%) and when heated (99C/30 min) it was further reduced to 13–18%, independent of the variety. Phaseolin (the main bean globulin) had, after heating, a digestibility similar to casein, but when heated in mixtures containing as low as 10% of the albumin fraction, it suffered a drastic decrease in its susceptibility to proteolysis. The chemical interactions that occur among the components of the albumin fraction that reduce its digestibility do not occur between phaseolin and albumins. Interactions between phaseolin and albumins depend on pH of heating and are responsible for differences in molecular weight distribution of peptides formed by the action of pepsin, but did not alter overall digestibility of the mixture. The low digestibility indeed was due to heat‐stable trypsin inhibitors found in the acid‐soluble fraction of the albumins. Lectins and α‐amylase inhibitors, glycoproteins of the albumin fraction, showed, in similar experiments, no effect on phaseolin digestibility, in spite of being very poorly digested even after heating .