[Rapid storage assay for the study of the loss of nutritive value of bean flour (Phaseolus vulgaris) proteins].

The loss of the nutritive value of bean flour protein was studied through a kinetic assay on the loss of available lysine of the flour at high temperatures (70-110 degrees C) and at different moisture contents. Lysine loss followed a first-order reaction kinetics; the activation energies for the different moisture levels were calculated and ranged between 8-13 kcal/mole. The moisture content had a very important effect on the rate of loss of available lysine. Kinetic parameters at high temperatures were used to predict the retention of available lysine at 34 degrees C; these values were in accordance with those obtained by storing bean flour with different moisture contents, at 34 degrees C.