Characterisation and control of polyphenol oxidase from red chicory (Chycorium intybus var. Chioggia)

Polyphenol oxidase (PPO) is an endogenous enzyme responsible for the enzymatic browning in food products. Food formulations containing red chicory experience a noticeable enzymatic browning due to the high concentration of PPO in this plant. This research focuses on the characterization and control of PPO activity of red chicory. The PPO activity in red chicory extracts was determined spectrophotometrically. The PPO activity in the white tissues of chicory was significantly higher (p <0.05) than in red tissues. Moreover, electrophoretic investigations were carried out to characterize the PPO in the obtained extracts. In the second step of this research, the inhibitory effect of different substances, such as ascorbic acid and citric acid, and different natural inhibitors, like fruit juices, were tested to control the PPO obtained from red chicory. Pomegranate juice was the most effective among fruit juices, inhibiting 47.1%. This research highlighted that natural PPO inhibitors could be a potential choice for the formulation of food products.