Czech Study Finds Adulterated Sea Buckthorn Oil Product Based on Low Price

Reviewed: Hurkova K, Rubert J, Stranska-Zachariasova M, Hajslova L. Strategies to document adulteration of food supplement based on sea buckthorn oil: a case study. Food Anal Methods. 2017;10:1317–1327.

Keywords: Adulteration, DART-qTOF-MS, HPLC-UV/Vis, Hippophae rhamnoides, sea buckthorn, UHPLC-qTOF-MS

Ingredients derived from the seed and the berries of sea buckthorn (Hippophae rhamnoides, syn. Eleagnus rhamnoides, Eleagnaceae), in particular the oil, are popular due to their nutritional content, e.g., vitamins C and E, carotenoids, mono- and polyunsaturated fatty acids, and terpenes. The seed oil is a richer source of polyunsaturated fatty acids than the berry, while saturated and monounsaturated fatty acids predominate in the berry oil.¹

The authors of this study investigated the authenticity of a commercial product obtained in a supermarket in the Czech Republic. The product was labeled to contain 100% sea buckthorn oil, but was sold at a much lower price than comparable products. Using direct analysis in real time quadrupole time-of-flight mass spectrometry (DART-qTOF-MS) and ultrahigh-performance liquid chromatography (UHPLC)-qTOF-MS, the researchers compared the mass spectrometric and chromatographic (in case of UHPLC) triglyceride fingerprints to those of authentic sunflower oil. In addition, the carotenoid composition was measured by high-performance liquid chromatography with visible detection at 425 nm.

The complete agreement of the chromatographic and spectral fingerprints with authentic sunflower oil confirmed the suspicion that the commercial product was adulterated, despite the fact that this product contained a substantial amount of β-carotene. Since the other carotenoids contained in sea buckthorn oil, e.g., lycopene and lutein, were not found, the authors believe that the sunflower oil was spiked with β-carotene, or a mixture of β-carotene with other carotenoids, to give the material a similar appearance to sea buckthorn oil.

Comment: Although several methods^2-5 have been published to detect adulteration of sea buckthorn oils with vegetable oils, there is little evidence in the peer-reviewed literature documenting such adulteration in commercial products. However, the higher prices compared to vegetable oils, and the relative ease to make a sea buckthorn oil “look-alike” make it a candidate for economically-motivated adulteration. The DART-qTOF-MS technology to measure the triglyceride mass spectrometric fingerprint is appealing because there is no sample preparation required, but the equipment is not common in quality control laboratories and quite expensive. Therefore, the evaluation of the carotenoid fingerprint by HPLC-UV/Vis may be a good option for routine identity verification of materials labeled as sea buckthorn oil. However, the method used by Hurkova et al. shows relatively poor peak resolution and may benefit from further optimization.

References

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2. Liu Y, Xiang L, Zhang Y, et al. DNA barcoding based identification of Hippophae species and authentication of commercial products by high resolution melting analysis. Food Chem. 2018;242:62-67.
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4. Giuffrida D, Pintea A, Dugo P, Torre G, Pop RM, Mondello L. Determination of carotenoids and their esters in fruits of sea buckthorn (Hippophae rhamnoides L.) by HPLC-DAD-APCI-MS. Phytochem Anal. 2012;23(3):267-273.
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