Litchi (Litchi chinensis Sonn.) is a subtropical to tropical fruit of high commercial value in international trade. However, harvested
litchi fruit rapidly lose their bright red skin colour. Peel browning of harvested litchi fruit has largely been attributed to rapid
degradation of red anthocyanin pigments. This process is associated with enzymatic oxidation of phenolics by polyphenol oxidase
(PPO) and/or peroxidase (POD). PPO and POD from litchi pericarp cannot directly oxidize anthocyanins. Moreover, PPO substrates
in the pericarp are not well characterised. Consequently, the roles of PPO and POD in litchi browning require further investigation.
Recently, an anthocyanase catalysing the hydrolysis of sugar moieties from anthocyanin to anthocyanidin has been
identified in litchi peel for the first time. Thus, litchi enzymatic browning may involve an anthocyanase–anthocyanin–phenolic–PPO
reaction. Current research focus is on characterising the properties of the anthocyanase involved in anthocyanin degradation.
Associated emphasis is on maintenance of membrane functions in relation to loss of compartmentation between litchi peel oxidase
enzymes and their substrates.