NIR shows its worth in fraudulent cinnamon detection

Near infrared (NIR) spectroscopy has become a go-to technology for identifying adulterated and counterfeit products, and that includes cinnamon – one of the most consumed and adulterated spices in the world – according to a new study.

Researchers from the University of Porto in Portugal assessed NIR and various chemometric statistical tools using a range of 133 samples made up to represent genuine cinnamon and material ;aced with the major adulterants used in real cinnamon, specifically Cinnamomum verum or Cinnamomum zeylanicum species.

In the marketplace, fraudsters bulk up cinnamon using adulterants like black pepper, clove and so-called "false" cinnamons including Cinnamomum cassia, Cinnamomum aromaticum, Cinnamomum burmannii and Cinnamomum loureiroi species. This adulteration practice is commonly performed in the powdered form which makes it difficult to detect.

Any adulteration of a foodstuff can pose risks to human health as it reveals a breakdown in the regular supply chain, and reduces confidence that the producer is adhering to procedures to ensure the safety of the product.

There is a steady stream of incidents involving cinnamon on the EU's Rapid Alert System for Food and Feed (RASFF) database, including for example the presence of contaminants like pesticide residues and drying agents, although that can equally occur with poorly processed genuine cinnamon.

Arguably more worrying is that Cinnamon cassia contains levels of coumarin up to around 1% – which is toxic to some animals and some sensitive humans, causing liver and kidney damage – whereas true cinnamon has a minimal amount at around 0.04%.

NIR has been proposed as a rapid, low cost, and non-destructive method of analysing cinnamon to make sure it has not been adulterated, and the new study – published in the journal Food Control – provides a tutorial on NIR and chemometric methods that can be combined to spot fraudulent samples.

The scientists report that NIR combined with a chemometric approach known as DD-SIMCA showed a sensitivity and specificity of 100% for cinnamon authentication, while another approach called MCR-ALS provided spectral profiles of adulterants that allowed them to be identified.

A third technique known as PLS is useful for quantifying the level of adulterants present in a sample, they report.

The team said that their work forms the basis of a protocol for dealing with counterfeit cinnamon samples using NIR spectroscopy.

Image by Jennifer Birgl from Pixabay