Enhancement of Bioactivity and Bioaccessibility of Food Phenolics: Structure Modification and Release from Food Matrices

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Phenolic and polyphenolic compounds are secondary metabolites that influence the quality of plant foods by serving as antioxidants to extend their shelf-life and also to protect cells and the body against damage by oxidative stress. The mechanisms for rendering beneficial effects of phenolics vary and may be independent from their antioxidant potential. Some phenolics are highly polar and insoluble in non-polar media such as fats and oils and also in crossing membrane bilayers to neutralize oxidants in the mitochondria. Generally, phenolics exist in the soluble and bound forms; the latter are not absorbed in the gastrointestinal tract and are only released in the colon, with limited benefits, thus their release during food processing would improve bioaccessibility and bioactivity. The goals set here will fill the existing knowledge gap in the literature. Therefore, unique properties and benefits, upon modification of chemical structures of phenolics and preparation of novel compounds from two bioactive molecules will be explored (OBJECTIVE 1). The phenolics to be tested include resveratrol, quercetin, tyrosol, hydroxytyrosol, and possibly pterostilbene, a methylated resveratrol, for the first time, and their lipophilization with bioactive fatty acids such as docosahexaenoic acid (DHA), and others or biomolecules like phytosterols and determination of their activities using chemical, instrumental, in-vitro and cell-line studies. An innovative method (steam explosion) that has recently been introduced to food science will be used to release bound phenolics from cell walls and compare the results with those from using enzymes, base or simulated digestion for their release. The test materials include seeds (lentils, camelina, sophia, chia), extracts and residues after extraction of soluble phenolics (OBJECTIVE 2). Finally, modified phenolics and those procured, both soluble and released bound fractions, will be tested for their efficacy in controlling oxidation in food systems such as meat, bulk oil and oil-in-water emulsion as well as in model systems of LDL cholesterol and DNA. In addition, anti-inflammatory and other benefits of the preparations will be examined in appropriate model- or cell-line systems. Further, inhibition of activities of -glucosidase and -amylase that deter the release of glucose and hence benefit diabetics as well as inhibition of acetyl cholinesterase, involved in cognitive function/Alzheimer's disease, will be explored (OBJECTIVE 3). The fundamental knowledge gained from these studies would advance the science behind functional foods/ingredients, and expand the use of novel phenolics in the design and formulation of foods with enhance benefits to health, and possibly pharmaceuticals. It would also be of benefit to the food technology industry, producing novel products for consumer benefit, and to government seeking to reduce health care costs.**