THE TRYPTOPHAN CONTENT OF PEARL-MILLET GRAINS AS A FUNCTION OF NITROGEN-CONTENT

The tryptophan content of pearl millet (Pennisetum thyphoides or P. am ericanum) was determined for 17 samples, using a procedure that allowe d the true quantity of this amino acid to be evaluated. The linear rel ationship found between the level of tryptophan in the dry matter and the nitrogen content of the grain was compared with the homologous one s published for foxtail millet and maize. The relationships for pearl and foxtail millets were characterized by close, if not identical, par ameters and by positive y-intercepts, indicative of higher tryptophan content in prolamins (2.4%) than in non-prolamin (1.2-1.4%) proteins. Comparatively, the slope of the relationship determined for maize was one-fifth of that for millets and the y-intercept was negative. A vari ability in the level of tryptophan in grain proteins was evidenced whe n this parameter was regressed against the reciprocal of nitrogen cont ent.