Scientists have recreated the flavour and scent of a grapefruit in the lab, using an orange. But the work was far from frivolous.
Oxford University science students’ magazine Bang! Science has the details.
Nootkatone is the molecule which gives this distinctive aroma, and is used worldwide in foods, drinks, and bathroom products. However, it takes around 400,000kg of grapefruit to produce 1kg of nootkatone, making it one of the most expensive ingredients in the world. It is also heavily reliant upon a good harvest, in an industry which is very sensitive to weather and disease.
But nor is synthesising the plant terpene in a lab any simple matter. The process uses some of the most complex reaction pathways in biology.
The University of Oxford spin-out company, BioTrans, looked to oranges as a way to improve production while avoiding man-made chemicals. They found that oranges produced a very similar compound, valencene, which when treated with a specially modified cytochrome P450 enzyme, was oxidised to nootkatone.
This new method complies with EU regulations for “natural” flavourings, and is vastly cheaper, as the supply of valencene is plentiful, even in years of poor orange harvest. The compound is found in the essential oil of oranges, a by-product of the juice industry.
“There are immense opportunities for the UK to lead the way in this technology. We are developing novel ways to produce high-value natural compounds without having to disrupt natural habitats or use man-made toxic chemicals that require careful disposal,” said James Brown of the, UK Knowledge Transfer Network.
Bill Condie is a science journalist based in Adelaide, Australia.