Chilling injury in mangosteen fruit

Major components of mangosteen (Garcinia mangostana L.) fruit quality include pericarp hardening, and shrinkage of both the stem and the sepals (calyx). At room temperature in South-East Asia (29-30degreesC) the fruit remains acceptable for about 6-8 d. To determine optimum storage temperature, fruit were stored at 3degrees, 6degrees and 12degreesC (88-90% r.h.). Unacceptable chilling injury symptoms were found within 5 d at 3degrees and 6degreesC. Symptoms were hardening of the pericarp, browning of the edible aril, and off-flavour. Early pericarp hardening was not correlated with increased lignin synthesis, but elevated lignin levels preceded hardening at later stages. Storage at 12degreesC produced acceptable levels of chilling symptoms, and therefore resulted in the longest storage life (20 d). Storage life at 12degreesC was limited by shriveling of the calyx and stem end. Calyces and stems were dipped in various concentrations of benzyladenine (BA), gibberellic acid (GA(3)) and I-naphthaleneacetic acid (NAA), either alone or combination, prior to storage at 12degreesC. BA delayed calyx and stem shriveling during storage, thereby allowing at least 25 d of storage. It is concluded that storage of mangosteen at 3 and 6degreesC induced unacceptable pericarp discoloration and pericarp hardening, whereas storage at 12degreesC did not. Dipping in BA can be used to extend the storage period at 12degreesC.