19-08-2014, 11:38 AM
The present work was undertaken with following objectives I) To optimize various parameters for the extraction of polyphenol oxidase (EC 1.14.18.1) from the peel of bottle gourd (Lagenaria siceraria) II) To study effect of various inhibitors on the enzyme activity III) Characterization of PPO and IV) To optimize downstream processing of the enzyme.
Enzymatic browning is one of the most devastating reactions for many exotic fruits and vegetables in particular tropical and subtropical varieties, which leads to major losses during processing of fruits and vegetables. Plant polyphenol oxidase(PPO) is responsible for enzymatic browning as it catalyzes the hydroxylation of monophenols to o-diphenols, which are oxidized to the corresponding o-quinones and subsequently polymerized to brown, red and black pigments. Such losses have prompted considerable interest in understanding and controlling activity of phenoloxidase in foods.
The present work was undertaken with following objectives I) To optimize various parameters for the extraction of polyphenol oxidase (EC 1.14.18.1) from the peel of bottle gourd (Lagenaria siceraria) II) To study effect of various inhibitors on the enzyme activity III) Characterization of PPO and IV) To optimize downstream processing of the enzyme.
Aqueous extraction of PPO was carried out by using a mixer grinder and by continuous rotation of the peels on an environmental shaker. The extraction yield of the enzyme was found to be higher using the grinder. Solvent system for extraction of enzyme was standardized. Butanol has given maximum extraction while pet. ether has in minimal. Buffers of different pH were used for extraction. The results showed that at pH 6 activity of PPO was maximum in a pH range 3 to 9. Effect of various inhibitors like EDTA, sodium metabisulphite and ascorbic acid were studied on the enzyme activity. The results showed that sodium metabisulphite was strongest inhibitor as compared to the ascorbic acid and EDTA.
Enzyme characterization and down stream processing studies of PPO are being carried out.