Detecting Adulterated Paprika: Identifying Quality and Authenticity Markers Using Advanced Headspace and Thermal Desorption with GC-MS

Spices are a popular food commodity globally,yet are some of the most commonly adulterated consumer products, either by mixing, substitution, misbranding or adding toxicants. Testing for adulteration typically involves solvent extraction techniques, heat treatments and sequencing. However, these methods can be laborious and time consuming, so a quick screening test to determine authenticity is beneficial.

In this study, several paprika samples of varying flavour and quality were tested, with some purposefully adulterated in the lab, using rice flour, to determine any major differences in the sample profile generated. Different masses of rice flour were added to 1 gram of paprika sample. Three sampling techniques coupled with GC-MS analysis were compared: static headspace-trap (HS-trap), HS-trap with multi-step-enrichment (MSE-HS-trap) and dynamic headspace using a microchamber (µ-CTE). HS and MSE-HS-trap were fully automated on the Centri 180 platform, as well as automated analysis of the dynamic headspace (DHS) samples collected on thermal desorption (TD) tubes.

Compared to HS-trap, MSE-HS-trap and DHS results show substantially more compounds detected, as well as an improvement of peak response due to higher volumes of the headspace being extracted. The multi-bed, backflush focusing trap in Centri enabled further analyte preconcentration while simultaneously allowing analysis of a broad analyte range, allowing screening of wide-ranging volatile organics that are potential quality and adulterant markers. Advanced data mining and chemometrics software further enhanced the analysis. All pure and adulterated paprika samples were clearly separated using a principal component analysis (PCA) plot, with tight clustering of replicates (n=5) for each sample analysed. Further analysis of the significant differences can highlight particular compounds as potential markers of authenticity.