Authenticity of spices and herbs – Metabarcoding allows for the analysis of plant species in complex mixtures
During the past couple of years the analysis of the authenticity and purity of food and raw materials has been increasingly gaining importance as a consequence of intensified international trade, evermore complex supply chains and last but not least media attention to single cases of food fraud and adulteration.
Therefore initiatives such as the Global Food Safety Initiative (GFSI) increase their focus on measures regarding Food Defense and Food Fraud next to classical measures on Food Safety.
Spices such as saffron, vanilla or cardamom are expensive and are traded across borders and via several intermediaries before they reach the consumer. Origin and varieties of spices such as vanilla or cinnamon contribute significantly to the taste quality and the price. Processes such as grinding and blending are critical points for adulteration.
The Eurofins‘ portfolio comprises a comprehensive set of analytical options to check and verify the authenticity and purity of a broad range of spices and herbs.
Molecular biological methods
The specific Real-Time Polymerase Chain Reaction (PCR) allows for the qualitative proof of plant species and varieties whenever the plant species is known. A semi-quantitative evaluation may be possible. The analysis of admixtures or fully unknown blends of several plant materials is by far more complex. In mixtures of two plant materials, Barcoding using Sanger Sequencing enables the identification of the main component and a minor component of at least 10 %.
The new Metabarcoding-Analysis using Next Generation Sequencing (NGS) allows now for the analysis of complex mixtures of more than two spices, herbs or other plant species in one single run – without any preliminary information about the expected species. The amplified sequences from the samples are compared with sequences from public databases. For example, the method can be used to elucidate the components of spice blends, such as masala mixtures. Plant species with a a relative amount of assigned DNA sequences of less than 0.5 % will not be reported. This so called cut-off of DNA sequences can not be correlated directly with the classical limit of detection of admixtured spices. But nevertheless, the new metabarcoding analysis is by far more sensitive than previous methods.
Further methods for the analysis of the authenticity of spices and herbs
Isotopic analyses such as the Site Specific Natural Isotope Fractionation-NMR (SNIF-NMR) and the Isotope Ratio Mass Spectrometry (IRMS) deliver isotopic fingerprints, which may provide information on the botanical or geographical origin of spices and herbs. Protonic NMR can confirm the authenticity of saffron – and equally of other spices and foodstuffs as long as reference materials are available.
Furthermore, classical chromatographical methods are applied for the analysis of valuable ingredients of spices and herbs.
For further information and consulting regarding the authenticity and purity of spices and herbs please contact our expert.