Results and Discussion 107 



Effect of Kojic Acid on Mushroom PPO Activity . .' .' .* .* .' ,' .* 107 



Effect of Kojic Acid on Potato PPO Activity .' 107 



Effect of Kojic Acid on Apple PPO Activity ] .' 114 



Effect of Kojic acid on Crustacean PPO Activity ....... 117 



Enzyme Kinetics 117 



Effect of Pre-incubation Temperature on PPO inhibition by 



Kojic Acid 12g 



Effect of Kojic Acid on the Hydroxylation Capabil'ity'of PPO . 129 



Effect of Kojic Acid on Oxygen Uptake by PPO Reaction .... 131 



Effect of Kojic Acid on Reduction of Cupric Copper 131 



Effect of Kojic Acid on Quinone Products ] ] I35 



Enzymatic Activities of Kojic Acid-treated PPO . . . 140 



Conclusion * * i^q 



EFFECT OF CARBON DIOXIDE ON THE INACTIVATION OF PLANT AND 



CRUSTACEAN POLYPHENOL OXIDASES I43 



Introduction I43 



Materials and Methods .............. 144 



Extraction and Purification of Lobster, Shrimp, and Potato' 



PPO 144 



Protein Quantitation and Enzyme Purity Determination. . . 145 



Enzyme Activity Assay ' 145 



Effect of Carbon Dioxide (1 atm) on PPO Activity. .*.".'**' 145 



pH Control Study ' ] 147 



Effect of High Pressure (58 atm) Carbon Dioxide on'ppo' 



Activity I47 



Kinetics of PPO Inactivation . . . 150 



Nondenaturing Polyacryl amide Gel Electrophoresis of Carbon* 



Dioxide (1 atm) -treated PPO 151 



Mass Balance of High Pressure Carbon Dioxide-treated and' 



Nontreated PPO 151 



Polyacryl amide Gel Isoelectric Focusing of Carbon Dioxide-' 



treated PPO 152 



Spectropolarimetric Analysis of PPO .' 153 



Study of Restoration of Carbon Dioxide-treated PPO Activity ' 153 



Results and Discussion _ 154 



Effect of Carbon Dioxide (1 atm) on PPO Activity.' . . .'.'"' 154 



Effect of Nitrogen on PPO Activity .' 157 



Effect of High Pressure Carbon Dioxide on PPO Activity ' 159 



Kinetics of PPO Inactivation ' 155 



Polyacryl amide Gel Electrophoresis of Carbon Dioxide'fi atm)' 



treated PPO 



Mass Balance of High Pressure Carbon Dioxide'treated'and' 



Nontreated PPO 158 



Polyacryl amide Gel Isoelectric Focusing of Carbon Dioxide-' 



treated PPO 172 



Spectropolarimetric Analysis of High Pressure Carbon'oioxide- 



treated PPO 172 



Restorative Ability of Carbon Dioxide-treated PPO Activity 186 



Conclusion * jgg 



168 



