Tracing the origin of Styrian pumpkin oil

Researchers in Austria have developed a way to test whether premium Styrian pumpkin seed oil is sourced from its native homeland of Austria or other parts of the world.

Pumpkin seed oil (Cucurbita pepo var. styriaca) sourced from the Styria region of Austria is sought after as a premium ingredient for use in salads, baking and cooking, as well as for its nutritional and medicinal qualities, so it is important to be able to distinguish it from inferior products sourced from other regions of the world.

The status of the oil was reinforced when it granted Protected Geographical Indication/Protected Designation of Origin (PGI/PDO) status by the European Commission in 1996 as part of efforts to protect the reputation, authenticity and competitiveness of foods that are closely associated with a particular region.

"The use of the denotation 'pure Styrian pumpkin seed oil' requires that this is 100 per cent pure and results from a first pressing procedure in local mills," say the researchers, from Austria's Montanuniversitaet Leoben.

They used a fingerprinting technique called inductively coupled plasma mass spectrometry (ICP-MS) to analyse the rare earth element (REE) composition of pumpkin seeds and oils from Styria as well as other geographic regions such as China and Russia.

REEs are a group of metallic elements that are known to be present in different concentrations and patterns in foodstuffs depending on the composition of the soil in the region in which they are grown, and measuring them via ICP-MS is already helping to authenticate wine, cheese, olive oils, honey and certain vegetables.

Using the technique, the scientists were able to show that pumpkin seeds and oils from different regions showed variations in REE fingerprints that were independent of ripeness and seasonal changes in weather conditions and were suitable for routine analytical testing.

This is thought to be the first time that the technique has been applied to pumpkin seed oil, and should allow genuine Styrian oil to be distinguished from oil produced in China and Russia, which are the two largest producers of pumpkin seeds worldwide.

"Economic interests are the driving force for the development of new analytical tools to verify traceability of pumpkin seed and pumpkin seed oil, to improve quality control and the identification of falsifications in order to protect local production," say the researchers.

The work is published in the journal Food Chemistry (Volume 136, Issues 3–4, 15 February 2013, Pages 1533–1542).