Trace elements in ginger can indicate a plant's origin

Researchers in their laboratory at Örebro University examined eleven products containing fresh and dried ginger bought from grocery stores in Sweden and Croatia, where the tropical herb originates from China, India, and Nigeria.

“We used strong acids to remove all organic material until we were left with only metals and semi-metals remaining in ionic solutions,” says Michaela Zeiner, senior lecturer in chemistry at Örebro University.

The Örebro researchers want to determine the presence of important nutrients such as potassium, calcium, and magnesium, as well as harmful elements such as lead, cadmium, and arsenic. A total of 29 elements were analysed in the ginger samples.

The researchers found that the levels of different elements differed more in fresh ginger than in dried ginger.

“This is because certain elements are reduced by homogenisation during drying and grinding,” says Michaela Zeiner.

The research model could be used to create a database of the elemental content of different plants. This database could serve as an important tool for detecting country-of-origin fraud in the food industry.

“You can compare it to fingerprinting in forensic science. Plant fingerprints reveal their origin,” says Michaela Zeiner.

Although the levels of toxic substances such as lead, arsenic, and cadmium varied, all the samples remained below the limits set by the World Health Organisation. In addition to geographical origin, soil and growing conditions also influence the levels of elements in the ginger studied.

The researchers also investigated whether the ginger had been contaminated by toxic substances from the packaging.

“We found no transfer of toxic substances from the packaging materials,” says Michaela Zeiner.