Sorting the spice rack: the cardamom conundrum


Dried capsules and seeds of cardamom, Ellateria cardamomum

Prized as a culinary staple around the world, it might have been thought there was little new to say about cardamom. Yet, molecular evidence set out in a scientific research paper* published in Taxon today (Wednesday, August 29), shows several species thought to belong in the same genus, Elettaria, must now be separated. 

Aromatic and enticing, the highly-appreciated green cardamom, Elettaria cardamomum (Zingiberaceae), has been cultivated for millennia in a number of tropical countries. It enhances dishes from Swedish buns to Indian biryanis and, as the third most expensive spice after saffron and vanilla, is of considerable economic importance. This species is the “type” or reference point of a genus, until now, including 10 species distributed in India, Sri Lanka, Peninsular Malaysia, Sumatra and Borneo.

MSc projects at the Royal Botanic Garden Edinburgh (RBGE) and the Natural History Museum, Oslo, later in association with Herbarium Bogoriense, Indonesia and Sarawak Forest Department, Malaysia, set out to include molecular methods to test if the cardamom genus, Elettaria, is a natural group. The ambition: to demonstrate a robust model for the analysis of the spice allegedly transported by the Vikings from the end of the Silk Road to Scandinavia.

In a bid to get as many samples as possible the seven authors led by Axel Dalberg Poulsen, of RBGE, conducted their practical research by collecting specimens from botanic gardens to spice shops and plantations, while undertaking fieldwork in SE Asia. The results revealed the need for a change in thinking. 

While samples from Sri Lanka, indeed, represented the true green cardamom, others from Malaysia and Indonesia failed to group with this. What’s more, a third cluster of samples representing plants exhibited for more than 50 years in botanic gardens – thought to be cardamom because of the smell of the leaves – were found to represent an unrelated branch of the ginger family, undetected for so long because they never flowered.

The study concludes that Elettaria is confined to India and Sri Lanka, possibly including three species. “The research helps make sense of some interesting quandaries,” explained Dr Dalberg Poulsen. “It had stirred our curiosity for a while that local people in Malaysia and Indonesia (including Wallacea) appeared uninterested in using cardamom, compared to the enthusiasm demonstrated in Sri Lanka and India. This solves the riddle: they look the same, but are tasteless and unrelated. “These plant species will now be placed in a separate new genus, Sulettaria. The good news is that green cardamom remains untouched and as pleasant as ever.”

The press release was developed by the Royal Botanical Garden Edinburgh press officers. 

Tags: press release, cardamom, Systematics, plants, spices
Published Aug. 29, 2018 7:40 AM - Last modified Aug. 29, 2018 7:43 AM