Influence of cooking methods on in vitro bioaccessibility of phenolics, flavonoids, and antioxidant activity of red cabbage

Red cabbage is rich in phytochemical compounds, and its consumption, either raw or cooked, has been linked to the prevention of several diseases. This work aimed to investigate the influence of cooking methods on in vitro bioaccessibility of phenolics and antioxidant activity of red cabbage. The vegetable was subjected to boiling, steaming, and microwaving for different times to evaluate color parameters, total phenolic (TPC), total flavonoid (TFC), anthocyanin content (AC), and antioxidant activity (FRAP, DPPH, and ABTS). The phytochemical bioaccessibility before and after cooking was also evaluated by in vitro simulated digestion. Steaming showed the most significant retention of the compounds after 20 and 25 minutes of cooking (72-86% for TPC, 72-77% for TFC, 75-79% for FRAP, 84-91% for DPPH, 70-83% for ABTS), followed by microwaving, which was more stable in 10 minutes. Microwaving decreased TFC and AC over time. Boiling did not show significant differences between the cooking times and showed more than 50% of losses of TPC, TFC, and AC and 30 to 60% of antioxidant activity. Steaming was the best cooking method, showing the most significant tendency to black coloration (< L*). In 10 minutes, it still showed the highest percentages of increase in TPC and the minor losses of TFC and AC in the gastric and intestinal phases. Steaming also increased the antioxidant after digestion when compared to uncooked red cabbage. These results are important to help consumers choose the most effective cooking method for red cabbage to retain its health-promoting components.