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Spectometer key to detecting coffee adulteration


May 16, 2018
By CANADIAN VENDING

Researchers from the Quadram Institute have developed a technique involving a benchtop spectrometer to distinguish between superior Arabica coffee and cheaper, lower quality Robusta beans.

A survey of ground roast coffee samples labelled as 100 per cent Arabica found that 10 per cent of these coffees contained significant levels of Robusta coffee, an inferior bean that is a cost-effective, due to its high growing yield, but produces substandard flavour. Many coffee retailers combine Arabica coffee with Robusta to reduce overall cost, but fraudulently label their product 100 per cent Arabica.

Current testing focuses on identifying 16-O-methylcafestol, also known as 16-OMC. It’s a process that takes three days, and is financially impractical for large-scale food fraud detection. The new method involving a NMR spectrometer from Oxford Instruments uses radio waves and strong magnets to get detailed information about the molecular composition of a sample, and the process only takes 30 minutes.

The Quadram Institute states that the spectrometer is sensitive enough to detect just 1 per cent Robusta in an Arabica/Robusta blend.

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The research was funded by the Biotechnology and Biological Sciences Research Council and published in the journal Food Chemistry. To characterise the NMR “fingerprint” of Arabica and Robusta beans, the scientists worked with colleagues from the Royal Botanical Gardens, Kew, who provided samples with a reliable source.