Synergistic Endo- and Exo-Interactions Between Blueberry Phenolic Compounds, Grape Variety Fractions, Chocolate Covered Strawberries, and Fruit Smoothies

The presence of phytochemicals in fruits and vegetables is considered to be of nutritional importance in the prevention of chronic diseases, such as cancer and cardiovascular disease. Through overlapping or complementary effects, the complex mixture of phytochemicals in fruits and vegetables provides a better protective effect on health than single phytochemicals. Previous studies have shown that synergistic interactions between antioxidants in food result in a higher antioxidant capacity than individually isolated antioxidants. Further work is needed to explore other potential synergistic interactions between antioxidant mixtures within foods (endo-interactions) and between foods (exo-interactions) commonly eaten together. A series of studies examined potential synergy between various components of blueberries, grapes, chocolate covered strawberries, and fruit smoothies using multiple antioxidant assays (ORAC, TEAC and DPPH). At the ratio found in blueberries, significant synergy, antagonism, and patterns were found for many phenolic compound combinations, though they were dependent on the assay. Significant synergy was found in the combinations of skin and juice as well as skin, juice, and seed across three grape varieties. Significant synergy was found in the combination of strawberry and 88% cocoa chocolate in fully dipped strawberries. Fruit smoothies made with blueberries (as opposed to strawberries and raspberries) and soymilk (as opposed to water) exhibited significantly higher antioxidant capacity. The 3 assays measured correlated weakly with each other. This work furthers our understanding of the potential value of complex mixtures and foods in the human diet and is the first to report on the combinations and fractions described.