A Pepsin Pancreatin Digest Index of Protein Quality Evaluation

Abstract

A pepsin pancreatin digest index was devised for a rapid, accurate estimation of protein quality. The index was calculated from the amino acids released by an in vitro digestion with pepsin followed by pancreatin. The amino acids were determined by automatic amino acid analysis which allowed rapid protein quality evaluations with very small samples. Using whole egg as a standard, excellent correlation was observed between the pepsin pancreatin index values for 12 proteins and their biological values reported in the literature from feeding trials. The proteins tested were selected to cover a wide range of protein quality. The pepsin pancreatin digest index values showed better correlation with the biological values for the growing rat than did the essential amino acid index which tended to overestimate the value, or the chemical score which tended to underestimate it.