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Controlled atmosphere and heat shock affect PAL1 and HSP90 mRNA accumulation in fresh-cut endive (Cichorium intybus L.)
Stored fresh-cut endive gradually turns red, since tissue wounding induces de novo synthesis of phenylalanine ammonia-lyase (PAL), which activates the phenylpropanoid pathway. Once the pool of phenolic substrates is increased, polyphenols are oxidized and cause discoloration. Modified atmosphere pac...
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Published in: | European food research & technology 2008-07, Vol.227 (3), p.721-726 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Stored fresh-cut endive gradually turns red, since tissue wounding induces de novo synthesis of phenylalanine ammonia-lyase (PAL), which activates the phenylpropanoid pathway. Once the pool of phenolic substrates is increased, polyphenols are oxidized and cause discoloration. Modified atmosphere packaging (MAP) and controlled atmosphere storage (CA) have been used to control browning. This paper describes the combined effects of heat shock (46 °C/120 s) and CA on the quality of cut endive stored at 10 °C. Heat shock protein (
HSP90
) and
PAL
expression patterns were analysed in endive sliced tissues. Real-time quantitative PCR (qPCR) was performed for
PAL1
and
PAL2
as well as for degenerated
HSP90
primers.
PAL1
and
PAL2
were strongly expressed in unheated cut tissues, in which maximum accumulation of
PAL1
mRNA occurred 12 h after cutting. Heat shock significantly reduced the level of
PAL1
transcripts in sliced endive, which was related to the prevention of discoloration. Controlled atmosphere storage had an effect on
PAL1
but not on
PAL2
transcription. Peak levels of
HSP90
transcript accumulation were found after 6 h, with an increasing and apparently cumulative effect of wounding and CA. Image analysis of the slices after 48 h clearly showed that heat-treated samples were similar to the control, with no significant difference between air and CA storage. These results show that there could be inhibition of
PAL1
isoform expression in endive slices after heating. |
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ISSN: | 1438-2377 1438-2385 |
DOI: | 10.1007/s00217-007-0778-6 |