Within the scope of the doctoral dissertation, we investigated the influence of different biotechnological processes (germination, fermentation, enzymatic treatment) on the content and accessibility of extractable and bound phenolic compounds in spelt seeds, as well as on their antioxidant activity in vitro and in vivo. The major phenolic compounds identified in spelt seeds were ferulic, p-coumaric, caffeic and p-hydroxybenzoic acids. When searching for the optimal conditions of abiotic stress during seed germination to produce the greatest increase in phenolics, germination at increased salinity and osmolarity without applied mechanical damage showed the highest increase in phenolic compounds content and antioxidant activity. Combining different biotechnological processes represents the more effective way to increase the content of phenolic compounds than a single process. The highest absolute content of extractable and bound individual phenolic acids was found in germinated seeds fermented with S. cerevisiae. Moreover, treatment of germinated and fermented seeds with five hydrolytic enzymes significantly increased the content of extractable phenolic compounds, but at the same time had a negative effect on the content of bound phenolic compounds. Phenolic compounds of germinated seeds could not protect the model organism S. cerevisiae from oxidation, whereas most extractable phenolic compounds from fermented and enzymatic treated seeds reduced intracellular oxidation. Greater cellular uptake of phenolic compounds does not necessarily mean greater antioxidant activity in vivo, in addition to the quantity, the form of phenolic compounds entering the cell is also important. The results suggest changes in the composition of the extracts during simulated in vitro digestion, since antioxidants of the same extract showed a different response against various free radicals compared to the raw seeds. The highest content of bioaccessible phenolic compounds was found in germinated seeds fermented with S. cerevisiae. Losses of phenolic compounds after digestion were high, however, the bioprocessed seeds still contained higher content of phenolic compounds compared to raw seeds.
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