Changes in physical characteristics and polyamines during maturation and storage of rambutans

Polyamine concentrations were measured in skin, pulp, and seeds of the late-harvest cultivar 'Rongrien' and the early harvest cultivar 'Seechompoo' rambutan (Nephelium lappaceum L.) fruit. Skin weight increased steadily until harvest in both cultivars. The pulp weight increased rapidly from 84 to 105 DAFB (harvest) in Rongrien and from 70 to 91 DAFB (harvest) in Seechompoo. Putrescine (Put) was the major polyamine in the skin, pulp, and seeds of rambutan. In general, it decreased early and increased late in fruit development. The increase of Put in the pulp coincided with that of the fresh weight. At harvest, total polyamine concentrations in the skin and pulp in late-harvest Rongrien were higher than those in early harvest Seechompoo. When Rongrien rambutan fruit were stored at 8 or 13 degreesC, chilling injury (CI) was detected in the skin of fruit stored 4 days or more at 8 C, and the CI index increased with days of storage. Put concentrations in the skin at 8 degreesC were higher than those at 13 degreesC, but Put concentrations did not rise correspondingly to the degree of CI. CI was not observed in the pulp, and the Put was much higher in the pulp than in the skin. These results suggest that Put concentration may be associated with the fruit growth and CI of rambutan. (C) 2001 Elsevier Science B.V. All rights reserved.