Premium
Peroxidase and polyphenol oxidase in long‐term frozen stored papaya slices. Differences among hermaphrodite and female papaya fruits
Author(s) -
Cano M P,
Lobo M G,
De Ancos B
Publication year - 1998
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199801)76:1<135::aid-jsfa949>3.0.co;2-9
Subject(s) - point of delivery , polyphenol oxidase , peroxidase , hermaphrodite , chemistry , horticulture , isozyme , cold storage , food science , botany , enzyme , biology , biochemistry
The effects of freezing and frozen storage on hermaphrodite and female papayas (cv Sunrise, solo group) polyphenol oxidase (EC 1.10.3.1; PPO) and peroxidase (EC 1.11.1.7; POD) were evaluated. The freezing process produces a significant increase in both enzymatic activities (22–11%, PPO and 13%, POD) depending on the kind of papaya fruit. During frozen storage, the soluble PPO activity shows a continuous increase up to 9 months of storage only in hermaphrodite tissues. This same sample also showed a significant activation of soluble POD at 3 months of storage. Female frozen samples maintained a continuous decrease in soluble POD activity during storage, while PPO activity showed some increase up to 12 months. Isoenzyme pattern of PPO in freshly frozen papaya tissues showed an intensification of the most cationic forms, D and E ( R f =0·55 and R f =0·64, respectively) and a disappearance of band B ( R f =0·28). This band B was not regenerated during frozen storage. However, female tissues only showed a continuous inactivation of bands D and E through storage. POD isoenzyme pattern showed different changes depending on the kind of papaya fruit. In both frozen papayas a new isoenzyme ( R f =0·39) form appeared at three months of storage. From this date, hermaphrodite frozen samples lost this isoenzyme together with original the most anionic POD form ( R f =0·58), increasing the intensity of the only remaining form ( R f =0·24). © 1998 SCI.