Our research is focused on qualitative and quantitative changes in biologically-active compounds of plant origin and the total antioxidative capacity of food in technological processes. Investigations cover phenolic compounds (phenolic acids, flavonoids, tannins), plant biopolymers (starch, proteins/lipids) of different botanic/plant origin, sulphur compounds (glutation, glucosinolates), inositol phosphates (IP-6 to IP-3), oligosaccharides (alfa galactosides), betalain pigments and antioxidative vitamins. Determinations are conducted for their potential activity in human prophylaxis and modelling rheological food qualities. Studies on gluten-free products involve analyses of gluten-free formulas with buckwheat flour supplemented with components improving their nutritive value and sensory attributes. Antioxidative properties of the above-mentioned compounds are studied in vitro and ex vivo, both following their isolation from the food product matrix as well as in the presence of other substances naturally co-occurring in food. We also investigate the effect of complex biopolymer systems on metabolic changes in the alimentary ecosystem and their potential bifidogenic functions. We also conduct studies on animals and in non-clinical medical trials on volunteers that address the bioavailability of biologically-active compounds in respect of changes proceeding in the food matrix upon technological processing.