Improving the shelf life of raspberries

Raspberries are one of the world’s most fragile fruits and have a relatively short shelf life compared to larger fruit. Food scientists at the Tasmanian Institute of Agriculture (TIA) have been investigating different packaging and processing methods that could help to improve the delicate fruit’s shelf life.

TIA PhD candidate Ky Nha (Nha) Huynh is helping to solve two interlinked problems for the Tasmanian berry industry: packaging and shelf life. The research is part of Huynh’s project with the ARC Training Centre for Innovative Horticultural Products, located at TIA.

“It’s really important that raspberries are stored well in the right packaging to optimise freshness and also to prevent damage,” said Huynh.

The hollow structure of berries means they need to be handled with care, including when being washed.

“Moisture gets into the berry, which can lead to reduced freshness after several days.”

Keeping berries fresh for longer is a ‘catch 22’: the berries lose moisture from refrigeration but need to be refrigerated to stay fresh.

Huynh is testing the quality of the berries after being stored for two weeks in different packaging and with different atmospheric conditions.

It’s no surprise that the packaging Huynh is testing is called ‘modified atmospheric packaging’, or MAP.

“MAP packaging, on its own, is not designed for any one specific fruit or vegetable. But because it’s sealed packaging, we can alter and test the levels of natural gases in the atmosphere,” Huynh said.

“I’m trying to determine the most beneficial atmospheric composition in the packaging.”

Packaging alone is not able to control mould and decay — it needs to be tailored to suit the produce — so Huynh is also researching processing methods which may help.

“Exact techniques, like using the right amount of water, are critical to the shelf life of the berries,” she said.

Huynh is conducting her research with Costa Berries, which supplied the raspberries for her trials.

Costa Senior Food Safety and Quality Assurance Specialist Ben Fisher has been working with Huynh on the project.

“There’s a lot of research and thought behind our products, and it’s fantastic to be collaborating with up-and-coming food scientists such as Nha,” Fisher said.

“The berry industry is only as good as the product, and freshness and shelf life are obviously essential to avoid food waste.

“This research will contribute to making sure our storage and packaging is as good as it can be using the latest technology,” he said.

The centre’s nine other PhD candidates are are also working to reduce Australia’s produce waste.

Findings of each of the projects will be presented at the Training Centre Conference from 20–21 March at the University of Tasmania, Sandy Bay.

Image caption: TIA PhD Candidate Ky Nha Huynh examines the fresh raspberries. Image credit: Claire Baker, Tasmanian Institute of Agriculture (TIA).