Measurement of the Net Utilization of Heat-Processed Proteins by Means of the Pepsin Digest-Residue (Pdr) Amino Acid Index

Abstract

The pepsin digest-residue (PDR) amino acid index was found to reflect the effects of heat processing upon the net protein utilization of proteins and mixed protein foods. Data are also presented which indicate that the discrepancy between the PDR index and the net utilization value of raw soybean meal is due to the presence in raw soybeans of substances which exert effects apparently unrelated to the enzymatic release of amino acids. The PDR index can be used to predict the net utilization of soybean meals accurately if these “toxic” factors are inactivated.