Scientists sniff out rotten avocados
Search for the hashtag #avocado on Instagram and it currently returns more than 9.5 million posts. From knitted avocado toys, to avocado greetings cards and, more recently, chocolate Easter egg avocados, every millennial worth their salt (or chilli flakes) has got in on the avo act.
But there’s one downfall to the green superfood, you can’t tell when its insides are less appealing green and more pond-like brown, often creating a lot of expensive waste.
Now, a team of UK scientists are working to invent a type of portable sniffing device that can detect whether avocados are rotten without breaking the skin and damaging the fruit – ensuring customers do not buy fruit that is already past its best.
Avocados are prone to developing various disorders in the flesh, such as fungal decay, grey pulp and vascular browning – not visible from the outside – resulting in around £40 million worth of poor quality fruit being thrown away every year in the UK alone.
A research team funded by UK Research and Innovation through the Science and Technology Facilities Council Food Network+ is working on a machine to detect these disorders in avocado using its aroma.
The team has identified a range of chemical markers that indicate whether the fruit is of poor quality. Ultimately, based on the heritage of developing instruments for space missions, the aim is to develop affordable, portable devices that can identify these markers and can be used by anyone at all stages in the value-chain.
The lead scientist, Dr Marcin Glowacz, a Post-Harvest Technologist at the Natural Resources Institute/University of Greenwich, said: “If these poor quality fruit could be identified prior to reaching the consumer they could be used for other purposes, for example in new product development and so reduce any negative environmental impact, rather than entering the market. Removing them from the supply chain before they reach the consumer would also have a positive impact on society, i.e. changing consumer behaviour so that people do not have to worry so much about the internal quality of the fruit, especially considering its premium price.”
Dr Glowacz is developing this new sniffing technology by working with space instrumentation expert Dr Geraint Morgan and his analytical colleagues Dr Simona Nicoara and Dr Sonia Garcia-Alcega of The Open University.
In partnership with the UK’s RAL Space research and technology facility, Dr Morgan was part of the team at The Open University that developed the Ptolemy instrument for the European Space Agency’s Rosetta mission that landed on a comet in 2014. Ptolemy was a shoe-box sized gas analyser that confirmed that the ‘building blocks of life’ are present on comets by sniffing and analysing the gases given off by it. Lessons learnt from this and other space missions will be applied to help to develop the avocado sniffer.
Preliminary results are promising and suggest that the detector would be sensitive enough to separate and detect numerous compounds and thus able to profile the differences between avocado fruit of different ripening stages and those with these disorders.
A longer-term experiment will need to be carried out to gather more statistically relevant data to build on these findings.
Dr Morgan, who works with Dr Simon Sheridan of Applied Science and Technology Solutions Ltd to commercialise his space technology research, said: “It is our theory that once the marker compounds associated with these flesh disorders are identified, it should be feasible to develop a small, robust, low power, portable system – based on the lessons previously learnt from the development of the Ptolemy instrument on the Rosetta mission – that is affordable and fit for purpose for the food industry.”
Find out more about the other projects being supported through the Food Network here.
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