A Pontificia Universidad Católica de Chile (PUC) study is looking at ways to deliver better kiwifruit to overseas markets when it comes to edibility, ripeness and quality. It is hoped the initiative will help ease the June-July overload and competition from New Zealand, with a process that delays ripening. At www.freshfruitportal.com we speak with project leader professor Juan Pablo Zoffori, who says a protocol has been developed that will be trialed this year.

The Chilean kiwifruit industry has aimed to improve its kiwifruit conservation practices for some time, finding the balance between fruit taste and achieving a less concentrated distribution over time.

Zoffori says the 'Improving the Edible Quality of Kiwifruit through Postharvest Fruit Conditioning and Maniuplation' project has made steps towards that goal.

"For a long time the research was focused on maintaining fruit firmness because it was a very important trade necessity," he says.

"Almost all the fruit comes together during the June-July period so an excess of supply is produced, and competition comes from New Zealand. You have to try to extend that supply to June-July-August-September."

In modified atmosphere research, scientists found an antagonistic relationship between Carbon dioxide and ethylene, which is the main hormone that accelerates ripening. Researchers also looked at I Methylcyclopropene (I-MCP) and its effects on fruit ripening, working out how to increase its commercial use in postharvest protocols.

"So with these two tools we worked on the concept of extending the supply of fruit."

Finding the right protocol

Early tests found while the fruit showed good strength it did not ripen well, and it was around this time that Zoffori's team started working in conjunction with the Chilean Kiwifruit Committee to improve edibility.

The protocol development has also focused on trade issues with timing.

"The protocol should be fairly advanced this season. We should have an answer and in fact we have already developed some ideas that we are going to implement commercially this season. We need to progress quickly," he says.

"The idea is to be already advanced with some commercial shipments in a way that next year we can say to companies with precision the way it has to be done."

He highlights New Zealand has always had a postharvest policy based on edibility with protocols that are much more developed than Chile's.

"New Zealand is more advanced from this point of view. They don't use modified atmosphere technology but controlled atmosphere is used partially, or you could say they give priority to the issue of edibility, with a fruit that is riper and less firm," he says.

He says the difference with Chile's protocol development is the focus on fruit conservation, through technology that can make the kiwifruit have a longer postharvest life and more firmness.

"Now we need these to end up being consumed and to have a good acceptance by consumers."

"The interesting thing about the project is that it is thinking about the consumer and that is tremendously valuable because the only way to increase consumption is allowing absorption of the large quantity of fruit that exists in the market."

Crossover benefits

The group's study has also looked at optimizing fruit edibility for peaches and nectarines, which have had large problems with mealiness.

"To ensure that consumption maturity is achieved, one needs to do something in this intermediate stage, and the species that requires this are pears, kiwifruit, peaches, nectarines, plums, but species like cherries and grapes don't require it."

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