Antibacterial activity of peptides and folding variants from milk proteins

Several milk proteins, such as immunoglobulins, lactoperoxidase, lysozyme and lactoferrin, have long been recognised for promoting health benefits in both newborns and adults. However, it has been shown that not only intact milk proteins but also derivatives thereof can participate in the host defence by exerting many kinds of biological functions. This review focuses on the use of technological processes to induce protein modifications aimed at the enhancement or generation of antibacterial activity. This includes the release of antibacterial peptides by enzymatic digestion, and proteins that exert antibacterial activity by acquiring a new conformation, such as the folding variant of α-lactalbumin or the lysozyme molecule. Current knowledge of antibacterial peptides is evaluated, paying special attention to the formation of these peptides by different proteolytic enzymes, their antibacterial effect, and, where relevant, the methods designed for their production. Finally, the contributions that demonstrate the in vivo health benefits of these compounds are also considered.