RESUMO
High-pressure processing (HPP) at 250-700â¯MPa for 30-45â¯min affects the colour parameters, phytochemical contents and antioxidant activities of purple waxy corn kernels (pâ¯<â¯0.05). The higher pressure-level, the lower L∗, a∗, b∗, C∗ and ho (pâ¯<â¯0.05). However, pressure-treated kernels at 700â¯MPa showed a similar colour profile to steam-treated kernels. HPP caused a loss in the total phenolic, flavonoid, and anthocyanin contents and antioxidant activities. The pressure-treated kernels had a higher phytochemical content than the steam-treated kernels. The phytochemicals and antioxidant activities decreased as the pressure increased from 250 to 550â¯MPa, but the levels recovered at 700â¯MPa. The longer holding-time, the greater loss of the compounds and antioxidant activities (pâ¯<â¯0.05). Pressure treatment at 700â¯MPa yielded the highest total phenolic and anthocyanin contents (pâ¯<â¯0.05). Water-soluble compounds can leach from food materials due to cell rupture. Nevertheless, HPP is a potential process to preserve the phytochemicals in food.