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Determination of the Geographical and Botanical Origin of Hops (Humulus lupulus L.) Using Stable Isotopes of C, N, and S

Ocvirk, Miha, Ogrinc, Nives, Košir, Iztok Jože
Journal of agricultural and food chemistry 2018 v.66 no.8 pp. 2021-2026
Humulus lupulus, analysis of variance, botanical composition, carbon, hops, mass spectrometry, nitrogen, provenance, stable isotopes, sulfur
A need exists for a reliable method to determine the geographical and botanical origin of hops. For this study, three sets of samples were collected: the first set comprised 5 German samples; the second set comprised samples of hops from 10 of the world’s major hop-growing regions; and the third comprised the 4 main Slovenian regions. The samples were analyzed using isotope ratio mass spectrometry (IRMS) to obtain δ¹³C, δ¹⁵N, and δ³⁴S values. The δ¹⁵N (2.2 ‰ to 8.4 ‰) and δ³⁴S (0.7 ‰ to 12.3 ‰) values were the most discriminating parameters for classifying hop according to geographical origin. ANOVA showed distinct groupings for 8 out of the 10 hop-growing regions. Although it was not possible to distinguish the geographical origin of hops based on δ¹³C (−28.9 ‰ to −24.7 ‰), in the case of botanical origin, δ¹³C values proved to be the most discriminative albeit with limited success.