Enrichment of phenolic antioxidants from cranberry (<i>Vaccinium macrocarpon</i>) to improve biological functionality
The aim of this dissertation research was to develop innovative strategies to enhance biological functionality and improve consistency of phenolic phytochemical profiles in cranberry products and byproducts.
Solid-state bioprocessing (SSB) of cranberry pomace with food grade fungi Rhizopus oligosporus and Lentinus edodes was used to mobilize phenolic antioxidants within a consistent phytochemical profile and improve biological functionality. The effect of SSB on antimicrobial activity was tested against three important food-borne pathogens Listeria monocytogenes , Vibrio parahaemolyticus and Escherichia coli O157:H7. Further, the antimicrobial activity of the extracts was also tested against gastric cancer and gastric ulcer-linked Helicobacter pylori. The results indicated that SSB mobilized functionally important phenolic phytochemicals such as ellagic acid and enhanced antioxidant activity. SSB also resulted in enhancing the antimicrobial activity of the extract. The results provided an insight into the mechanism of antimicrobial activity of phenolic phytochemicals.
Cranberry synergies with functional biphenyls ellagic acid and rosmarinic acid were designed for enrichment of antioxidant, anti-H. pylori, antimutagen and DNA protection properties. Results indicated that cranberry synergies with biphenyls improved their antioxidant activity. The antimutagenic and DNA protective functions properties of cranberry synergies were found to be significantly higher than pure compounds. Cranberry synergies linked to enhanced antioxidant activity and phytochemical profile also improved the antimicrobial property of the extract against gastric ulcer-linked H. pylori. The anti-H. pylori activity of cranberry was further enhanced by synergistically blending cranberry extract with other fruit and herb extracts.
The mechanism of action of these cranberry synergies with biphenyls on modulating the antioxidant enzyme response was investigated in germinating fava bean sprouts and oxidatively stressed porcine muscle tissue. From this investigation phenolic antioxidants from plants appear to mediate their biological functionality by modulating antioxidant systems in eukaryotes by more than one mechanism. These functions were carried out either as free radical scavenging antioxidants and more importantly by inducing antioxidant enzyme responses in the cellular systems. The results also indicated that pure biphenyls functioned more efficiently when they were in a cranberry background. The results provide an important insight into the possible mechanism of action of fruit phytochemicals in biological systems and also showed that they can be improved in synergy with specific biphenyls. (Abstract shortened by UMI.)