CHARACTERIZATION OF PROTEIN HYDROLYSATES PREPARED FOR ENTERAL NUTRITION

A method is described for the comprehensive characterization of protei n hydrolysates for enteral nutrition. It includes (1) gel filtration o n a 0.9 x 250 cm column of Sephadex G-25F eluted with 5% acetic acid, to prepare pools; (2) amino acid analysis with and without acid hydrol ysis to determine the amounts of peptide bound and free amino acids; ( 3) reaction with TNBS to determine the amount of NH2-terminal groups; and (4) calculation of number-average peptide size of pools from TNBS and amino acid data. The preparation of three hydrolysates of casein w ith pancreatic enzymes on the industrial scale (5000 L) is described. The number-average peptide size distribution of hydrolysate B, Hydroca se, was 18 % free amino acids, most of which were essential; 62 % pept ides containing 2-9 residues; and 20% peptides containing 10-40 residu es. The number- and weight-average peptide size distribution of Hydroc ase is similar to that reported by the manufacturer of Peptamen, and b oth differ from the casein hydrolysate in Pregestimil and Nutramigen r eported by the manufacturer to contain 50 % free amino acids by amino acid analysis.