STRUCTURE, FUNCTIONS AND APPLICATIONS OF LACTOPEROXIDASE IN NATURAL ANTIMICROBIAL SYSTEMS

Lactoperoxidase (LPO) is quantitatively one of the most prominent enzy mes in bovine milk; it catalyses the inactivation of many species of m icro-organism in a lactoperoxidase system (LP-s). LP-s is harmless to mammalian cells and is also identified as an antimicrobial system in h uman saliva, milk and tears. The introduction of industrial processes for the recovery of LPO from milk and whey has renewed the interest in this enzyme as a natural antimicrobial tool for extending the shelf-l ife of milk and food products. During the last two decades the detaile d chemistry of bovine LP-s has been elucidated. The major products res ponsible for the antimicrobial effects of LP-s have been characterized under conditions in which some micro-organisms will be killed and oth ers are inhibited in their growth. Recent studies indicate that the fi eld of actual and potential applications of these natural antimicrobia l systems may be very broad. In this paper several aspects of LP-s are reviewed with respect to its application possibilities in food produc ts. Starting with structure and properties of LPO, attention is focuss ed on the mechanism of its biological function in LP-s. Subsequently f actors involved in the preservation of this function during food proce ssing are discussed, and finally special attention is paid to the real and potential applications of LP-s in a number of food products. The general conclusion is that LP-s can be regarded as a naturally occurri ng antimicrobial system, which is a part of the biological defence aga inst bacterial infections. In addition, other biological functions of LP-s are being observed in relation to human health and welfare. In vi tro applications of LP-s are of in creasing interest for preventing un due proliferation of contaminating micro-organisms in food products.