[Fortification of bread with bean flour (Phaseolus vulgaris). II. Nutritive value of the fortified bread].

The protein value of breads containing bean flour (BF) (Phaseolus vulgaris, cv Tórtola) was tested in rats. BF replaced wheat flour by 2, 4, 6, 8 and 10 per cent. Protein content was 9.3 (N x 5.7) per cent and 24.4 (N x 6.25) per cent for wheat flour and bean flour, respectively. The protein content in the control bread was 11.6%, and increased to 12.6% at the 10% level of substitution. Parameters measured were protein efficiency ratio (PER), net protein ratio (NPR), and apparent and true digestibility of the protein. PER, in the control bread, was 1.44; a slight, non-significant increase occurred up to the 10% level of substitution. The control bread showed a NPR value of 2.78, figure which also remained practically unchanged at the higher levels of replacement. Nevertheless, both apparent and true protein digestibility decreased significantly with increasing levels of substitution of WF by BF (p less than 0.05). In conclusion, substitution of WF by BF in bread did not produce the expected increase in protein quality under our experimental conditions.