Apple flavonoids: isolation and characterization for antioxidant properties in selected food systems

There is a growing interest in discovering naturally occuring antioxidants as food additives because of their benefits in preserving food wholesomeness and their potential health benefits. Lipid peroxidation is a common process in food that could cause loss of food quality and adverse health problems for the consumers of affected products. In general, dietary antioxidants protect molecules such as lipids, DNA and proteins in the body, which are susceptible to oxidative stress. Beyond the antioxidant properties, intake of dietary polyphenolics such as flavonoids have been inversely associated with incidences of human chronic diseases. Apples are a major food source of flavonoids. Flavonoids are known for their free radical scavenging properties and protective ability against cancer, heart disease, and other chronic diseases. Therefore, identification of apple flavonoids with specific antioxidant properties that prevent oxidative damage to foods will allow not only for the replacement of potentially toxic synthetic antioxidants but will also improve human health upon the consumption of food products supplemented with flavonoids. The overall goal of the proposed research program is to understand the structure and function relationship of specific flavonoids present in apple and their by-products with the ultimate goal of developing commercially exploitable bio-products such as value-added food ingredients. This project will investigate health friendly extraction techniques including supercritical fluid extraction to extract flavonols, the predominant group of flavonoids, from apple skin. Centrifugal partition chromatography followed by mass spectrometry and nucleic magnetic resonance techniques will be used to isolate and characterize specific flavonols. The extracts and isolated flavonols will be assessed for their antioxidant capacity and ability to prevent lipid peroxidation in selected laboratory, food, and animal model systems. Counter assays will also be used to eliminate flavonols at risk of producing toxic effects.