Distinction between Cranberry and Lingonberry Fruit Using UHPLC-MS

Reviewed: Hurkova K, Uttl L, Rubert J, Navratilova K, Kokourek V, Strenska-Zachariasova M, Paprstein F, Hajslova J. Cranberries versus lingonberries: a challenging authentication of similar Vaccinium fruit. Food Chem. 2019;284:162-170.

Keywords: phenolic compounds, UHPLC-MS-MS, Vaccinium macrocarpon, Vaccinium vitis-idaea

Possibly initiated by the success of cranberry (Vaccinium macrocarpon, Ericaceae) juice and cranberry dietary supplements in the market, products derived from lingonberry (Vaccinium vitis-idaea) have gained popularity in European countries. Traditionally used for jams, lingonberries in the form of juice and food supplements are marketed for the prevention of urinary tract infections based on the similarity of the chemical composition with cranberries, relying on data from clinical trials using cranberry products.

Most of the lingonberries are collected in the wild. Because of the more labor-intensive harvest, the need to access more remote areas for collection, and the smaller fruit compared to cranberry, lingonberries are sold at a higher price than cranberries. This provides an incentive for economically-motivated adulteration, although, to our knowledge, there is no evidence of such a practice.

The authors of this study analyzed 33 frozen or dried samples each of cranberry and lingonberry from two different harvest years by ultra-high-performance liquid chromatography with quadrupole-time of flight mass spectrometric detection (UHPLC-qTOF-MS). Samples were obtained from the Research and Breeding Institute of Pomology Holovousy, Czech Republic, or from retail stores in the Czech Republic, Sweden, or Norway. Berry samples were extracted with methanol using a horizontal shaker, centrifuged, and analyzed. Data from the qTOF-MS were submitted to principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). Cranberries and lingonberries were readily separated into distinct clusters, independent of the geographical origin of samples.

Finally, a loadings plot of the PLS-DA data was used to identify marker compounds that correlate with fruit distinction. The most important compounds affecting the separation into two clusters were tentatively identified as glycerophospholipids and polyphenols. Peonidin glycosides, myricetin-3-O-glucoside, and myricetin-3-O-arabinoside were found to be markers for the cranberry cluster, while catechin and ferulic acid were correlated to the clustering of lingonberries.

Comment: While the use of lingonberry dietary supplements to prevent urinary tract infections has become quite popular in certain European countries, any benefit claims are mostly based on the presence of high amounts of A-type PACs rather than results from clinical studies.¹ One study from Finland suggests that drinking a cranberry-lingonberry juice mixture helps to prevent urinary tract infections in women.²

Jungfer et al. distinguished between cranberry (V. macrocarpon and V. oxycoccus) and lingonberry using catechin, epicatechin, and PAC dimers and trimers. The results corroborate data from the paper by Hurkova et al.³ that epicatechin is the predominant monomer in cranberry, while catechin is dominant in European-grown lingonberry.¹ However, Canadian lingonberry had similar catechin and epicatechin content. Those who do not have a UHPLC-qTOF-MS (or similar LC-MS) instrument in their lab may look at the anthocyanin patterns of cranberry and lingonberry. Brown et al. have shown that peonidin-3-O-galactoside and peonidin-3-O-arabinoside found in cranberry are absent in lingonberry, confirming the results from this investigation.^3,4

References

1. Jungfer E, Zimmermann BF, Ruttkat A, Galensa R. Comparing procyanidins in selected Vaccinium species by UHPLC-MS² with regard to authenticity and health effects. J Agric Food Chem. 2012;60:9688-9696.
2. Kontiokari T, Sundqvist K, Nuutinen M, Pokka T, Koskela M, Uhari M. Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women. BMJ. 2001;322(7302):1571.
3. Hurkova K, Uttl L, Rubert J, Navratilova K, Kokourek V, Strenska-Zachariasova M, Paprstein F, Hajslova J. Cranberries versus lingonberries: a challenging authentication of similar Vaccinium fruit. Food Chem. 2019;284:162-170.
4. Brown PN, Turi CE, Shipley PR, Murch SJ. Comparison of large (Vaccinium macrocarpon Ait.) and small (Vaccinium oxycoccus L., Vaccinium vitis-idaea L.) cranberry in British Columbia by phytochemical determination, antioxidant potential, and metabolomic profiling with chemometric analysis. Planta Med. 2012;78(6):630-640.