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Creating a healthier cuppa

Pistacia terebinthus. Photo: Flickr/fturmog

A close relative of the pistachio nut could provide a healthy decaf alternative to coffee, according to researchers from the Universities of York and Gaziantep in Turkey.

Scientists found that when roasted correctly, Pistacia terebinthus offered a similar attractive aroma and flavour to coffee – but without the undesirable effects.

Research Fellow Dr Mustafa Özel, from York’s Department of Chemistry, says: “There are lots of important anti-oxidants in Pistacia terebinthus which are beneficial to health and, importantly, do not contain caffeine. Pistacia coffee could therefore provide a healthier alternative to conventional coffee.”

The coffee as it is sold and prepared  in TurkeyIn Dr Özel’s native Turkey, Pistacia terebinthus – a close relative of the snack we know as the pistachio nut (Pistacia vera) – is sometimes dried, roasted and ground, and used as a coffee substitute. The whole fruit from the tree is used including the nut kernel inside, the shell and the surrounding flesh.

Conventional fresh coffee beans, picked in high-altitude tropical regions, bear little resemblance to the coffee enjoyed by millions across the world. The familiar smell and taste of coffee only appear after roasting.

Roasting triggers the aroma due to the release of organic compounds that exist as vapours, called volatiles. Familiar volatiles include limonene which smells of citrus and alpha-pinene which has a pine/turpentine scent.

Dr Özel from York and Dr Fahrettin Gogus from Gaziantep investigated what makes Pistacia terebinthus so like coffee by looking at which volatiles are released at various stages of roasting, as well as the ideal roasting time needed to produce the best aroma while keeping undesirable products to a minimum.

Although the conventional coffee bean and Pistacia terebinthus fruit might be very different when raw, after roasting they have a remarkably similar aroma

Dr Mustafa Özel

“Roasting time and roasting temperature really affect the production of many volatile compounds,” explains Dr Özel. “As some particular compounds are mainly responsible for the characteristic aroma of the roasted product, you can manipulate which ones appear by altering the roasting time and temperature.”

The results, published in Food Chemistry, show that the most volatiles are produced after 20 minutes of roasting at 200 degrees Celsius.

“Although the conventional coffee bean and Pistacia terebinthus fruit might be very different when raw, after roasting they have a remarkably similar aroma,” says Dr Özel. “Pan roasting produces furans, furanones, benzene derivatives, pyrazines and other volatiles typical of coffee aroma and flavour. This suggests that Pistacia terebinthus might provide a viable alternative for the coffee industry and could be commercialised more broadly as a coffee substitute.”  

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