Enhancing fruit preservation with nanotechnology

January 09, 2019
Women from one of the Mango Growing Domains in Tamil Nadu are being given skills.
IDRC / Vijay Kutty

Post-harvest losses of mangoes in India and Sri Lanka are as high as 40% annually (equivalent to losses of more than CA$800 million per year). Now breakthrough research has developed a natural and affordable way to reduce the loss of mangoes and other soft fruits by delaying ripening — which could increase the incomes of nearly one-third of the population in these countries.

A natural way to prevent post-harvest fruit losses

A team of researchers from India’s Tamil Nadu Agricultural University and private sector companies discovered that a key enzyme called phospholipase D (PLD) triggers the deterioration of membranes, consequently accelerating fruit ripening. Further research led to the discovery of a natural plant extract called hexanal that significantly inhibits the action of PLD. Based on these findings, scientists from Canada, India, and Sri Lanka developed and tested hexanal nanotechnologies (technologies that manipulate matter at a molecular level) on fruit crops. Prototypes were developed that could deliver hexanal in very small doses and in a sustained manner using “green nanotechnology”.

A researcher conducts a hexanal fumigation experiment on mangoes.
IDRC / VIJAY KUTTY

This safe and ecofriendly product evaporates within 24 hours, leaves no trace on the fruits, and mass quantities of fruit can be treated within five minutes. Working with institutions in Kenya, Tanzania, and Trinidad and Tobago, the research team is building on this success by studying hexanal applications with other fruits under various growing conditions.

Nine biodegradable nanotechnology solutions have been developed, including a post-harvest dip, a spray for fruit still on the tree, and hexanal-impregnated packaging (made from materials such as banana fibre) to protect the fruit during shipping to overseas markets.

Field trials using pre-harvest sprays and post-harvest dip applications of hexanal demonstrated two main benefits of the technology: its ability to retain fruits on trees longer, especially mangoes, and a longer shelf life, especially for bananas. Spraying mango orchards with a low concentration of the compound slowed fruit ripening by three weeks and applying the hexanal spray after harvest increased the fruit’s shelf life by up to 17 days.

A roadside mango vendor in Krishnagiri, India.
IDRC / BARTAY

Now thousands of smallholder farmers have a natural and affordable way to reduce post-harvest losses of mangoes and other fruits. The innovations improved supply management by extending the growing and selling season. This prevents market glut, which enables farmers to sell their produce at a higher price. A longer growing and selling season has also increased employment, primarily for women who are involved in production and post-production activities (e.g., harvesting, sorting, packing, selling, and accounting). Additionally, hands-on training to produce mango-based pickles, sweets, and other foods has helped women enhance their household income by 10%.

Scaling up solutions

The research partners are working to commercialize hexanal products with the intent of making them readily available for small-scale farmers. Enhanced Freshness Formulation (EFF) is on track to be commercially available in India and Sri Lanka in 2018-2019. Uptake of EFF products among farmers and packers in India is conservatively estimated to reach 100,000-150,000. Canada and the United States are expected to follow in late 2019 or 2020 once regulatory hurdles have been cleared.

A farmer in India sprays mango trees with hexanal.
IDRC / VIJAY KUTTY

The Canadian International Food Security Research Fund is jointly funded by Global Affairs Canada and IDRC.

Learn more about this project and its outcomes.