Comparative studies on the polyphenoloxidase fraction from lobster and tyrosinase

Inactivation of polyphenol oxidase from Pacific white shrimp by dense phase carbon dioxide

“…2a) showed that the activity of the PPO gradually increased from 4°C to 44°C and decreased from 44°C to 60°C, thus the optimum temperature of PPO from Pacific white shrimps was about 44°C. The optimum temperature of PPO from different crustacean species was about 40-45°C (Simpson et al, 1987), while the optimum temperature of PPO from lobster (Homarus americanus) and tiger prawn (Penaeus japonicus) was 30°C (Montero, Ávalos, et al, 2001) and 55°C (Opoku-Gyamfua, Simpson, & Squires, 1992), respectively. Other researchers reported that the optimum temperature of PPO from deepwater pink shrimp (Parapenaeus longirostris), Western Australian lobster (Panulirus cygnus) and Florida spiny lobster (Panulirus argus) increased continuously up to 60°C (Giménez, Martínez-Alvarez, Montero, & Gómez-Guillén, 2010;Montero, Ávalos, et al, 2001;Zamorano et al, 2009).…”

“…2b) showed that the activity of PPO was stable from 25°C to 40°C and no remaining activity could be found after incubation for 30 min at 72°C. A number of PPOs from different shrimp and prawn species were stable from 20°C to 40°C (Montero, Ávalos, et al, 2001;Opoku-Gyamfua et al, 1992;Zamorano et al, 2009). …”

Seafood Enzymes and their Potential Industrial Application

“…Stability of PPO varies over a number of factors such as temperature, pH, substrate, ionic strength, buffer system, and time of incubation, apart from source and environmental factors [56]. Most of the PPO are heat-labile, except lobster PPO, which is reported to exhibit thermotolerance [57]. PPO in crustacean species results in post-harvest melanosis and related quality problems [58].…”

Partial purification and kinetic characterization of mushroom stem polyphenoloxidase and determination of its storage stability in different lyophilized forms

“…The quinons formed undergo non-enzymatic polymerization reactions resulting in the formation of dark colored melanins [2][3][4]. This reaction initiated by PPO is called enzymatic browning and it causes loss of quality during processing of fruits and vegetables, mushrooms and some crustacean species [2,5,6]. Thus, different methods such as chemical inhibition or heat inactivation of PPO has been developed to prevent this reaction during food processing [2,7].…”