It is well known that, apart from nutritional value, proteins also possess biological and physicochemical properties. For example, milk contains a wide range of proteins that provide protection against enteropathogens or are essential for the manufacture and characteristic nature of certain dairy products. Research carried out during the last 10 years has shown that the caseins and whey proteins can be an important source of biologically active peptides (Schanbacher et al. 1998). These peptides are in an inactive state inside the protein molecule and are released during enzymatic digestion
. Bioactive peptides usually contain 3 to 20 amino acid residues per molecule. Biologically active peptides have been found to have specific activities, such as antihypertensive, antioxidative, antimicrobial, immunomodulatory, opioid or mineral-binding activities (Table 6.1). Many milk-derived peptides reveal multifunctional properties, i.e., specific peptide sequences may exert two or more
different biological activities. Due to their physiological and physicochemical versatility, milk-borne bioactive peptides are regarded as highly prominent ingredients for health-promoting functional foods or pharmaceutical preparations. The formation and properties of milk protein-derived peptides have been reviewed in many recent articles (Clare and Swaisgood 2000; Korhonen et al. 1998; Meisel 1998; Meisel and Bockelmann 1999; Xu 1998; Yamamoto 1997).