shrimp) PPOs. In addition, kojic acid was capable of reducing o-quinones 

 back to di phenols and prevented melanin formation. 



The inactivation of lobster, brown shrimp, and potato PPO by CO2 was 

 studied. When exposed to CO^ (1 atm) at 33°, 38°, or 43°C, lobster PPO 

 showed a decline in enzyme activity with treatment time. Studies on 

 inactivation kinetics revealed that PPO was more labile to CO^ and heat 

 than to heat alone. The use of polyacryl amide gel electrophoresis showed 

 that there were no differences in protein patterns and isoelectric 

 profiles between the CO^ (1 atm) -treated and untreated PPO. When lobster, 

 brown shrimp, and potato PPOs were subjected to high pressure (58 atm) CO^ 

 at 43°C, the inactivation of these PPOs followed trends similar to the 

 atmospheric COg experiments. Crustacean PPOs, however, were more 

 susceptible to inactivation by high pressure COg than by atmospheric CO2. 

 Differences in the secondary structures between the high pressure CO^- 

 treated and the nontreated PPO were evident by spectropolarimetric 

 analysis. 







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