BIOACTIVE PEPTIDES DERIVED FROM MILK-PROTEINS - INGREDIENTS FOR FUNCTIONAL FOODS

Besides other animal and vegetable proteins milk protein is currently the main source of biologically active proteins which were detected fo r the first time in 1979 in partial enzymatic hydrolysates of milk pro teins. Although in the last two decades a number of biochemical and ph ysiological studies have been performed on bioactive peptides, which w ere accessible mainly via in vitro proteolysis of caseins and whey pro teins or obtained by chemical synthesis of potentially bioactive prote in sequences, little attention has been paid to regulatory peptides in terms of their nutritional importance. The discussion on health enhan cing food - ''functional foods'' - has revived the relevance of bioact ive peptides as ingredients of these foods. The aim of this paper is t o review the state of the art of the actually known bioactive peptides derived from milk proteins, to which opioid agonistic and antagonisti c activities are ascribed, which produce inhibitory effects on the ang iotensin I-converting enzyme (ACE), show immunomodulatory, antimicrobi al and antithrombotic activities or may exert carrier functions for mi nerals in the gut. Particular attention is directed towards the physio logical significance of bioactive peptides as exogenous regulatory sub stances. Their role as ''food hormones'' (or 'formones'') needs, howev er, further clarification although a number of studies indicate the re gulatory potential of these peptides after ingestion of casein hydroly sates. According to the present state of knowledge the use of caseinop hosphopeptides and ACE-inhibitory peptides as ingredients of ''functio nal foods'' is promising.