Researchers have turned to nanotechnology to ensure harvested tropical fruit stays fresher for longer.

In a bid to assist small farmers in India and Sri Lanka, a multi-million dollar research project has harnessed a naturally occurring chemical that can prolong shelf life.

Mangoes are the second largest fruit crop in India and the third largest crop in Sri Lanka, however large production losses cost farmers and their communities millions of dollars annually.

Associate Professor Jayasankar Subramanian at the University of Guelph in Canada is working with colleagues in India and Sri Lanka to address these huge post harvest losses.

"Almost 35 to 40 per cent of the total production is lost, mainly because they do not have proper storage or sufficient time to take the fruits from the villages to the marketplace."

Dr Subramanian said the answer to increasing the shelf life of fruit lies in nanotechnology which, up until now, had mainly been used in engineering science.

The technology, developed by an international research team, coats the fruit and delays the break down of its external membrane, prolonging its shelf life.

This nanofilm is made from a naturally occurring chemical compound derived from agricultural waste products - the fibres are extracted from coconut husks and banana plants.

"We've found a naturally occurring product that most plants have and will produce upon any injury called hexanal," Dr Subramanian said.

"This hexanal is able to stop an enzyme called phospholipase D and because of that the membranes remain fresh and stable and the ripening gets delayed slowly, fruits remain firmer and fresh-looking.

"That's how we're extending the shelf-life of the fruits."

The chemical compound or hexanal is sprayed onto the mango trees a week or two prior to harvest, while fruit such as bananas can be dipped in the chemical.

Dr Subramanian said there was no lingering effect for the consumer.

"The compound dissipates relatively quickly so there won't be any adverse effects of that chemical," he said.

"Another part of this research is harnessing these biological nanoparticles in a new packaging system by placing sachets of the hexanal compound inside packing boxes.

"That sachet will release the hexanal in a sustained manner and the member integrity will be kept longer so when the fruit reaches the receiver it will be much fresher than what they're getting now."

The project by the Canadian Government's International Development Research Centre and International Food Security Research Fund is funded through Foreign Affairs, Trade and Development Canada.

Researchers anticipate the packaging technology to prolong freshness will be commercially viable within two years, and would work for all sorts of perishables including lychees and rambutans, as well as mangos and bananas.

(ABC News)