Peptides

Abstract

Dolores Gonzaález de Llano Centro Nacional de Biotecnología (CSIC), Madrid, Spain Tomás Herraiz and M. Carmen Polo Instituto de Fermentaciones Industriales (CSIC), Madrid, Spain Peptides are present naturally in foods, arising mainly from the partial degradation of protein polypeptide chains. Some peptides, like the dipeptides carnosine, anserine, and balenine in vertebrate muscle or glutathione in fruits, are nonproteinic in origin. In other cases, peptides are present in foods because they are used as additives (sweeteners, flavor enhancers, bulking agents in light drinks, etc.). Enzymatic hydrolysis of food proteins yields peptides that are of great interest to the food industry and are utilized for various purposes, e.g., improving the functional properties of foods, flavoring agents, in dietetic food, parenteral feeding (casein hydrolyzates), or milk protein substitutes in cases of intolerance. The multiple functions of peptides in foods (anti-oxidants, antimicrobial agents, interfacial agents) and their role in the development of characteristic flavors (sweetness, bitterness), as well as the information they can provide about the genuineness of foods, make peptide analysis a necessity. Both producers and government laboratories have considerable interest in the study of peptides, both for research purposes and for the control of raw materials or manufactured foods. For this reason, substantial attention is now being focussed on the development of analytical techniques designed to separate, characterize, and quantify peptides.