A peptide composition derived from a protein composition when added to uncooked food effects moisture retention during cooking of the food. The peptide composition is derived from a dry protein mixture or an aqueous acidic protein solution which, in turn, is derived from animal muscle tissue. The peptide composition is added to uncooked poultry, meat or fish prior to cooking. The dry protein mixture and aqueous acidic protein solution comprise myofibrillar proteins and sarcoplasmic proteins substantially free of myofibrils and sarcomeres.