Determining the physiochemical changes and time of chilling injury incidence during cold storage of pomegranate fruit

Department of Horticultural Science, College of Agriculture, Shiraz University, Shiraz, Iran (1,2)
Department of Horticultural Science, College of Agriculture, Jahrom University, Jahrom, Iran (1,2)

Corresponding author: l_taghipoor@yahoo.com
Abstract:

Intermittent warming (IW) is a good postharvest technique to prevent or alleviate chilling injuries during cold storage. Performing the warming treatment at the period of time before chilling injury is irreversible during storage, and it is the first prerequisite for a successful IW treatment. In order to determine the fruit physiochemical changes and time of irreversible chilling injury incidence during cold storage of pomegranate fruit (cv. Rabab-e-Neyriz), this research was conducted. Fruits were stored at 2 ± 0.5 °C and 90 ± 5% relative humidity for 90 days. At 15-day intervals, 40 fruits (four replicates and 10 fruits in each replicate) were sampled and further stored at 20°C for 3 days (shelf life). Chilling injury (CI) index and weight loss (WL) in intact fruits, electrolyte leakage (EL) and K leakage (KL) in peel samples, total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio and pH in fruit juice were measured. With respect to quality parameters, TSS did not change significantly under cold storage. According to TA changes, the TSS/TA ratio was decreased up to 30 days but subsequently increased and the highest ratio was detected at the end of storage, which was significantly higher than the TSS/TA ratio at the harvest time. Results related to CI index, WL, EL and KL showed that pomegranate fruits could be stored cold without significant chilling damages up to 30 days. It was suggested that performing the IW treatment during this period could be concomitant with desired effects in long-term storage of this commercial cultivar. 

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