Chlorophyll degradation in the bract of dragon fruit (Hylocereus spp.)
2015
Kammapana, L. | Jitareerat, P. | Wongs-Aree, C. | Srilaong, V. | Yamuchi, N.
Loss of greenness in the bract due to chlorophyll (Chl) degradation is one of the symptoms of senescence in dragon fruit (Hylocereus spp.). Chl degradation enzyme activities (chlorophyllase – Chlase, Mg-dechelatase – MD, chlorophyll-degrading peroxidase – Chl-POX and pheophytinase – PPH), Chl derivatives (chlorophyllide a – Chlide a, pheophorbide a – Pheide a, pheophytin a – Phein a and 132-hydroxychlorophyll – OHChl a), and Chl content were assayed during storage at 25°C. Chl a content decreased with storage while Chl b content remained unchanged. Chlase activity increased after one day of storage and decreased thereafter. MD and PPH activity increased gradually for the first two days of storage while Chl-POX activity increased during the first five days of storage and then decreased. Chlide a, Pheide a and OHChl a were undetectable throughout storage, while Phein a increased during storage. The results indicate that MD and PPH may be involved in Chl degradation. Chl derivatives, particularly Pheina, were accumulated as intermediate products during Chl degradation.
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