Effect of temperature on the kinetic behaviour of polyphenol oxidase and peroxidase in fresh-cut lettuce

A. B. Martin-Diana, D. Rico, C. Barry-Ryan, J. Mulcahy, G. T.M. Henehan, J. Frias

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Activity levels for polyphenol oxidase (PPO) and peroxidase (POD) enzymes were exanimate in crude extracts and showed significantly higher values in photo- synthetic tissue than in vascular tissue. Time courses at 50 °C showed a rapid loss of POD activity and a similar but slower loss of PPO activity in all tissue while incuba- tions at 4 °C and 25 °C showed no significant loss of activity over the same time period. The thermal treatment of the extracts (50 °C) caused a decrease in the PPO and POD activities over time, in all the samples. PPO had less dependence on temper- ature than POD. The model prediction for PPO and POD for the first one minute at 50 °C has little effect on either enzyme with the loss of ~6 % of the total activity. Minimal processed lettuce washed at 50 °C and stored at 4 °C during 10 days showed significantly lower PPO and POD activity throughout the storage period than those washed at 4 °C and 25 °C in the same conditions.

Original languageEnglish
Title of host publicationInternational Conference Postharvest Unlimited Downunder 2004
PublisherInternational Society for Horticultural Science
Pages149-156
Number of pages8
Volume687
ISBN (Print)9789066056985
DOIs
Publication statusPublished - 2005

Publication series

NameActa Horticulturae
Volume687
ISSN (Print)0567-7572

Keywords

  • Browning
  • Heat-shock
  • Photosynthetic tissue
  • Salad-cut lettuce
  • Vascular tissue

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