Mature Litchi fruits (cv. Guiwei) were obtained from a commercial
orchard in Chaozhou, PR China. The fruits were pruned,
cleaned, and selected for uniformity of shape, color and size
(weight 25 g, diameter 3 cm). Selected fruits were pre-cooled to a
fruit temperature of 10 C in an ice water mixture and then
transported to the laboratory in a foam box on ice, and stored at
4 C for no more than 6 h, prior to use in the following colorprotecting
treatments. Fruit samples, except for controls (fresh
litchi fruit), were dipped in boiling water for 7 s (Olesen et al.,
2004), followed immediately by cold water dipping treatment for
1 min, and immersion in 50 g/L citric acid and 20 g/L sodium
chloride for 2 min (Ducamp-Collin et al., 2008). Subsequently, 100 g
batches of treated fruits were packed into nylon composite polyethylene
bags (1 sample/bag), vacuum-packed (0.09 MPa) andpre-cooled at a refrigerating chamber until the interior temperature
of the fruits reached 0 C (±1 C) prior to the freezing process.