Estimation of Gross Protein Value

THE AVAILABLE lysine test of Carpenter and Ellinger (1955) could not be applied generally to proteins of plant origin without modifications; and even then, it would not be as reliable as it is in the case of proteins of animal origin. Plant proteins, in general, lack more than one essential amino acid, and for this reason prediction of their nutritive value through their available lysine content alone is a matter still to be proved. On the other hand, physical techniques of protein solubility in various solutions were reported by Anwar (1957) to work as grading tests for protein quality of plant origin. His results could be summarized as follows: in the case of cottonseed meals the residual protein fraction as determined by the Lund-Sanström fractionation technique (1943) seems to be the most reliable fraction in the prediction of their nutritive value. The globulin protein fraction, though with significant results, …