Abstract: A protein hydrolyzate is produced from mucosa tissue of pigs, cattle or sheep by providing an aqueous mixture of the tissue, hydrolyzing the tissue with a proteolytic enzyme at a salt concentration of less than 0.1 molar to produce a digest solution containing a protein hydrolyzate and polyanions including heparin, adsorbing the polyanions on an anion exchange resin, recovering the anion exchange resin containing adsorbed polyanions to provide a digest solution containing less than 2.9 u/ml residual heparin and recovering the protein hydrolyzate from the digest solution by screening or dehydration. The protein hydrolyzate contains less than 15% ash, between 9.5 and 11.5% total Kjeldahl nitrogen and between 5.0 and 7.0% alpha amino nitrogen. The protein hydrolyzate may be used in nutritional formulations such as to promote weight gain in newly weaned livestock and in medical formulations such as peritoneal dialysis fluids and formulations for use in enteral and parenteral mutrition.