Determination of protein and reactive lysine in leaf-protein concentrates by dye-binding.

1. Twenty leaf-protein concentrates (LPC), were produced from different crops and by different processes, the latter being designed to retain maximum nutritional value of the samples. 2. The establishment of conditions for the use of CI ACid Orange 12 in a commercial dye-buffer reagent for the determination of protein and reactive (available) lysine in LPC was investigated. 3. Values for protein by dye-binding correlated well with those for tungstic-acid-precipitated nitrogen (x6.25). 4. Some LPC samples showed a loss of reactive lysine, the greatest loss being associated with the most severe processing conditions. 5. For the LPC samples studied, dye-binding provided a convenient method for the concurrent determination of protein and reactive lysine.