Effect of food combinations and their co-digestion on total antioxidant capacity under simulated gastrointestinal conditions

This study aims to investigate the antioxidant interactions between mostly co-consumed foods in daily diet. Total antioxidant capacities of individual and the binary combinations of certain food samples from different groups including fruits, vegetables, grain sources, dairy and meat products were measured. The types of interactions (synergism, antagonism, and additive) between food samples were determined by a statistical comparison between estimated and measured total antioxidant capacity. The results revealed an antagonism in the combinations of milk with the fruits or green tea extract while a clear synergism was reported in the combination of fruits with breakfast cereal, whole wheat bread, or yoghurt. The selected foods were also subjected to in vitro digestion protocol. Slightly alkaline conditions were found to significantly (p < 0.05) increase the total antioxidant capacity of foods. Synergism was observed during the digestion of the combinations of milk with fruits or tea extracts. Hydroxyl radical scavenging capacity was also determined in the bioaccessible fractions of foods. Green tea extract was found to be the most efficient scavenger (936.48 ± 16.64 mmol TE.kg(−1)).