Milk Protein Fractions: Assessment of Bioactivities for Applications in Functional Foods

Milk proteins are increasingly used in a variety of functional foods and nutraceuticals including protein drink mixes, sport meals, protein bars, high-protein cookies and chewable protein tablets. The most commonly used ingredients are represented by whey protein concentrates and isolates however the recent advances in preparative fractionation of milk protein bring more products to the functional food market including alpha-, beta- and kappa-caseins, beta-lactglobulin, alpha-lactalbumin, lactoferrin, glycomacropeptide and other minor proteins and peptides. The biological activity of major milk protein fractions (casein and whey protein) has been investigated using animal models and humans. On the other hand, the study of minor milk protein fractions may further explain the mechanisms by which casein and whey protein influence blood glucose and food intake. Furthermore, the use of individual milk protein fractions may provide some new insight on the endocrine mechanisms regulating glucose metabolism and relevant physiological functions. Another largely unexplored area is the effect of food processing, such as high temperature, on the biological activity of milk protein fractions. While biological activities of milk protein are determined in experiments with protein solutions prepared under the standard state conditions, many foods with added proteins are processed with heat treatment or pressurizing required for their preservation or textural changes. The main objective of this program is to elucidate the biological activity of individual milk protein fractions, assess their bioactivities and formulate the prototypes of functional foods with added bioactive milk protein fractions. Using the small laboratory animals, the physiological mechanisms related to energy homeostasis and blood glucose control in response to the intake of pure milk protein fractions will be evaluated. Then the fractions with proven biological activity will be tested in human participants to establish the lowest efficacy dose required to reduce blood glucose or suppress food intake. The final step of the project will include the formulation of functional foods containing the effective dose of bioactive milk protein fraction and their sensory analysis with a trained taste panel. Another evaluation of biological efficacy will be used for the processed prototypes to determine whether food processing changes their biological benefits. This program has a potential to expand in the future and test the biological activity of other food ingredients used in functional food products.