Enzymatic and Color Changes During Post‐harvest Storage of Lychee Fruit

Abstract

t Hunter color dimension scores were related to loss of red color and darkening during post-harvest storage of fresh lychee fruit at 4°C. Peroxidase declined whereas polyphenyloxidase increased in the lythee endocarp during storage. The peroxidase of the exocarp increased to 36.93 U/min at 29 days, but declined during subsequent storage.No change in polyphenyloxidase of the exocarp was observed until 29 days when activity increased nearly ten fold to 0.55 U/min. The decrease in peroxidase and increase in polyphenyloxidase activities coincided with onset of discoloration of fruit.

Oxidation of (−)-epicatechin is a precursor of litchi pericarp enzymatic browning

“…However, the fruit rapidly loses its bright red colour and turns brown once harvested. Postharvest browning of litchi was thought to be caused by the rapid degradation of the red pigment and oxidation of phenolic compounds by polyphenol oxidase (PPO), producing brown-coloured products (Akamine, 1960;Huang, Hart, Lee, & Wicker, 1990;Jiang, Zauberman, & Fuchs, 1997;Tan & Li, 1984).…”

Integrated application of 1-methylcyclopropene and modified atmosphere packaging to improve quality retention of litchi cultivars during storage

“…Pericarp browning and decay limit the storage life of litchis. The browning mechanism in litchi is reported to be a result of oxidation of anthocyanins by polyphenol oxidase (PPO) (Huang et al, 1990;Jiang, 2000) or peroxidase (POD) (Zhang et al, 2005). Commercially a strong antioxidative treatment, sulphur dioxide (SO 2 ) fumigation, has been adopted to block the oxidation reactions involved in browning.…”

Exotics

“…Thus, during postharvest storage of lychee fruits there may be a loss of red-colouration and a darkening of the fruit. Coincident with the onset of fruit discolouration is a decline in peroxidase (EC 1.11.1.7) activity and an increase in the activity of polyphenoloxidase (EC 1.10.3.1; PPO) (Huang et al, 1990). It has been demonstrated that fruit colour may be preserved by S02 fumigation, followed by a dip in dilute HCl, and is the result of an inhibition of PPO activity (Zauberman et al, 1991).…”