The bioaccessiblity and antioxidant potential of purple rice polyphenols following simulated gastrointestinal digestion

Purple rice bioactive compounds, specifically polyphenols, are known to possess a wide range of disease preventive properties that are attributed to their antioxidant and anti-inflammatory activity. Previous studies have focused on profiling phenolic composition and antioxidant potential using chemical extracts. However these methods may not be biologically relevant due to the chemical and enzymatic changes that occur during digestion. This study, therefore, aimed to extract phenolic compounds using simulated in vitro gastrointestinal digestion in order to determine the impact on the total phenolic content, phenolic composition and antioxidant potential during the different digestion phases. Results indicated a significant increase in total phenolic content and antioxidant potential post digestion that was mainly attributed to enzymatic release of compounds from the cereal matrix. Phenolic profiling of digested rice samples identified the presence of some of the antioxidant phenolic compounds found by chemical extraction, and their metabolism during the phases of digestion. These results present simulated gastrointestinal digestion as a more biological relevant approach to phenolic extraction while providing a metabolic insight into the fate of phenolic compounds during digestion.