PEROXIDASE AND POLYPHENOL OXIDASE ACTIVITIES IN DEVELOPING PEACHES

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Abstract
Peroxidase (POD) and polyphenol oxidase (PPO) activities were monitored during the development of peach fruit (Prunus persica Batsch w. Redhaven) from shalk split stage to full maturation. Two extraction methods gave a discrepancy in activity for both enzymes. Two peaks of POD activities were observed and they corresponded to the two weight gain periods of the peaches. Polyphenol oxidase activity was very high at early development stage and declined to a constant level after the pit‐hardened stage. Hydrophobic chromatography, using Phenyl‐Sepha‐rose CL‐4B resin, provided a rapid partial purification and characterization of peach PPO. Several apparent forms of PPO and constant changes of these forms during development were observed. Upon cold storage of the acetone powder of peaches, an additional PPO isozyme much more tightly bound to the hydrophobic resin was noted. The technique could be very useful in studies of other food enzymes.