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Dietary proteins are known to carry a wide range of nutritional, functional and biological properties. Nutritionally, the proteins are a source of energy and amino acids, which are essential for growth and maintenance. Functionally, the proteins contribute to the physicochemical and sensory properties of various protein-rich foods. Furthermore, many dietary proteins possess specific biological properties which make these components potential ingredients of functional or health-promoting foods. Many of these properties are attributed to physiologically active peptides encrypted in protein molecules. Particularly rich sources of such peptides are milk and egg, but they are also found in meat of various kinds as well as many plants. These peptides are inactive within the sequence of parent protein and can be released during gastrointestinal digestion or food processing. Depending on the amino acid sequence, these peptides may exert a number of different activities in vivo, affecting, e.g., the cardiovascular, endocrine, immune and nervous systems in addition to nutrient utilization. There is increasing commercial interest in the production of bioactive peptides from various sources. Industrial-scale production of such peptides is, however, hampered by the lack of suitable technologies. Bioactive peptides can also be produced from milk proteins through fermentation of milk, by starters employed in the manufacture of fermented milks or cheese. In particular, antihypertensive peptides have been identified in fermented milk, whey and ripened cheese. A few of these peptides have been commercialised in the form of fermented milks. There is a need to develop technologies which retain or even enhance the activity of bioactive peptides in food systems. Also, it is essential to study the optimum utilization of such peptides during passage through the gastrointestinal tract. more...

Milk proteins are known to exert a wide range of nutritional, functional and biological activities. Apart from being a balanced source of valuable amino acids, milk proteins contribute to the consistency and sensory properties of various dairy products. Furthermore, many milk proteins possess specific biological properties which make them potential ingredients of health-promoting foods. These properties are attributed to both native protein molecules and to physiologically active peptides encrypted in the protein molecules. Considerable progress has been made over the last twenty years in technologies aimed at separation, fractionation and isolation in a purified form of many interesting proteins occurring in bovine colostrum and milk. Industrial-scale methods have been developed for native whey proteins such as immunoglobulins, lactoferrin, lactoperoxidase, alpha-lactalbumin and beta-lactoglobulin. Their large-scale manufacture and commercial exploitation is still limited although validated research data about their physiological health benefits is rapidly accumulating. Promising product concepts and novel fields of use have emerged recently, and some of these molecules have already found commercial applications. The same applies to bioactive peptides derived from different milk proteins. Active peptides can be liberated during gastrointestinal digestion or milk fermentation with proteolytic enzymes. Such peptides may exert a number of physiological effects in vivo on the gastrointestinal, cardiovascular, endocrine, immune, nervous and other body systems. However, at present the industrial-scale production of such peptides is limited by a lack of suitable technologies. On the other hand, a number of bioactive peptides have been identified in fermented dairy products, and there are already a few commercial dairy products enriched with blood pressure-reducing milk protein peptides. There is a need to develop methods to optimise the activity of bioactive peptides in food systems and to enable their optimum utilisation in the body. This review highlights existing modern technologies applicable for the isolation of bioactive native proteins and peptides derived from bovine colostrum, milk and cheese whey, and discusses aspects of their current and potential applications for human nutrition and promotion of human health. more...