QUALITY OF ‘VALENCIA’ ORANGES DURING LOW TEMPERATURE STORAGE

Abstract

The quality of non waxed (control) and waxed ‘Valencia’ oranges was evaluated during a storage at 2 °C and 6 °C, and after marketing conditions (20 °C for six days). Every week during the cold storage, the fruits were evaluated for: Maturity index (total soluble solids/titratable acidity), color (a/b ratio), weight loss, chilling injury (CI), and decay. The maturity as determined by the SST/TA ratio varied during storage at 2 and 6 °C, with values that ranged from 8.7 to 18.8 on the control, and from 10.9 to 17.6 on waxed oranges. Waxing reduce weight loss during cold storage and under marketing simulated conditions (except those fruits stored previously at 6 °C). A weight loss of 9.1 % was registered on the oranges after they were stored for ten weeks at 6 °C. Waxing did not reduce chilling injury (CI). The symptoms of chilling injuries began to appear on the waxed oranges after five weeks of being kept under temperatures ranging from 2 to 6 °C, with values of 14 and 2 %, respectively. Non-waxed fruits showed lower incidence for the same storage time. It was observed that these symptoms increased during cold storage, reaching values up to 46 % after 10 weeks at 2 °C. Higher CI values were observed when oranges were transferred to the simulated marketing conditions. Rotting incidence was low during cold storage. Rotting was not observed until the 9th week in up to 16 % of the non-waxed fruits. However, rotting notably increased when the oranges were transferred to environments with higher temperatures (20 °C) for 6 days, reaching values up to 60 % of the non-waxed fruits previously stored for 10 weeks at 2 °C. A lower rotting incidence was observed on waxed fruits during cold storage and simulated marketing conditions. CI is the most important quality disorder that limits the orange shelf life during low temperature storage.