New method improves long-term storage of kiwifruit

A simple and non-contaminant technology method may be the answer to improving the quality of kiwifruit during long-term storage.

Kiwifruit became a popular food choice for consumers following its introduction to the world market from New Zealand in the 1950s, but one of the challenges for growers is its susceptibility to severe disorders during storage.

A new study from Iran recommends heat and calcium treatments to extend storage life and improve quality in kiwifruit.

“A combination of heat treatment followed by calcium (Ca) dip for controlling postharvest pests and/or diseases has had satisfactory results in maintaining or improving the texture of several products,” said authors Shirin Shahkoomahally and Asghar Ramezanian from Shiraz University, who published the study in the March 2015 issue of HortScience.

“However, there was no research on postharvest application of Ca and hot water on qualitative parameters of kiwifruit during cold storage. This research evaluated the effect of hot water combined with Ca solution treatments to maintain qualitative characteristics of kiwifruit during cold storage.”

The researchers from the university’s Department of Horticultural Science treated mature, unripe kiwifruit (Hayward) with hot water for 5, 10 and 15 minutes at 47°C then dipped them in a 2% w/v CaCl₂ solution and stored the kiwifruit at 0°C for up to 120 days. During storage, fruit were sampled at 0, 30, 60, 90 and 120 days for postharvest quality evaluation.

“Our analyses showed that fruit firmness decreased during cold storage, and the rate of decrease was significantly higher in control fruits compared with those treated with hot water and calcium treatments,” the authors said.

Results also showed that hot water and calcium treatments significantly suppressed colour development of kiwifruit stored at 0°C for 120 days compared with calcium-only treatments.

The report said this suggests that “hot water and calcium treatments have a potential to act as an alternative colour loss prevention method for long-term storage”.

Fruits dipped in hot water and calcium also showed a significant difference with respect to total phenolics, which was associated with lower polyphenol oxidase (PPO) activity. Heating combined with calcium dips significantly reduced PPO activity during 120-day storage.

The complete study and abstract are available on the ASHS HortScience electronic journal website: http://hortsci.ashspublications.org/content/50/3/412.abstract.

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