Effects of Intermittent Warming on Quality of Papaya Fruit cv. Holland during Storage

Abstract

Papaya (Carica papaya L.) is a tropical fruit grown widely in Thailand. However, the export
volume is low which could be due to temperature mismanagement during storage
and transportation that lead to low quality fruit. This research investigated the effects of
intermittent warming (IW) on ‘Holland’ papaya during storage. Papayas with 25% peel
yellowing were submitted to four conditions: untreated fruit stored at 5°C (control), 15°C,
IW1 condition (5°C for 4 days then subjected to 15°C for 1 day, 1 cycle) and IW2 condition
(5°C for 4 days and moved to 15°C for 1 day, 2 cycles) then stored at 5°C, 90% RH until the
end of storage. The quality of papayas was evaluated periodically at 0, 5, 10, 15 and 20 days
of storage. The results showed that weight loss of fruit in all treatments was lower than 1.2%
throughout the storage period. Fruit stored at 15°C, 80% RH had significantly (p < 0.05)
higher in peel color changes (L* and a* values) compared with other treatments at 5 and
10 days of storage. Total soluble solids and titratable acidity revealed non-significant
differences among treatments throughout the storage period. The fruit stored at 15°C had
the highest vitamin C content of 34.3 mg 100 g-1 FW, but they could be kept for 10 days.
The control fruit could be stored for only 5 days due to the unacceptable chilling injury (CI)
index (>2) was observed since 10 days of storage. The more severity of CI symptoms for the
control fruit developed quickly after that. In contrast, the quality of fruit stored under
IW1 and IW2 were still acceptable with the CI index of 1.8 and 0.8, respectively at 20 days
of storage. The IW2 treatment potentially reduced the severity of CI and retained storage
quality of fruit for 20 days.