POLYPHENOL OXIDASE INHIBITOR(S) FROM GERMAN COCKROACH ( BLATTELLA GERMANICA ) EXTRACT

Enzymatic browning causes millions of dollars in losses yearly to the food industry by discoloration of fruits and vegetables. Food and Drug Administration's banning of sulfites in 1986 has created a large field of research in search of natural, effective and economic inhibitors of enzymatic browning. The objective of this research was to demonstrate inhibition of plant(s) polyphenol oxidase (PPO; EC 1.10.3.1) using inhibitor(s) from the extract of German cockroach, Blattella germanica . Crude cockroach extract inhibited apple PPO activity 60–70% and potato PPO 15–25%. Inhibition occurred rapidly in the reaction mixture and was dependent on the pH of the system. The inhibitor(s) appear(s) to be large based on ultrafiltration studies and loss of inhibition with proteases. PRACTICAL APPLICATIONS An extract from German cockroach appears effective in inhibiting browning on apples and potatoes. Successful identification of inhibitor(s) of polyphenol oxidase (PPO) from German cockroach would be useful to the fruit and vegetable segments of the food industry, due to the losses they incur from enzymatic browning. Identifying and understanding the mechanism of inhibition on fruit and vegetable PPOs could lead to inexpensive alternatives to prevent browning. Eventually a commercial spray or dip using a purified form of the inhibitor may be developed as an inexpensive treatment to preserve fruits and vegetables.