Hops (Humulus lupulus L.) is a species that grows spontaneously in Corsica, but the characterization of this species in this territory has not yet been investigated. The main objectives of this study are to explore the features of wild hops from Corsica and to determine the effect of the island terroir on some cultivars in the first year of growth. A multidisciplinary approach consisting of the genetic analysis, morphological comparison and chemical characterization of essential oils was carried out on four wild Corsican hops and three hop cultivars grown in Tettnang, Germany and Corsica, France. The morphological and GC-MS analysis of Corsican wild hops, set cluster coastal samples apart from the one far from the coast. This dissimilarity is supported by the SSR analysis by two of the three coastal accessions. The genetics demonstrate a proximity between the European noble cultivar Tettnanger and the mountain Corsican wild hop from Corte. The morphological comparison between German hops cultivated in Tettnang and in Corsican soil, and the GC-MS characterization of their essential oils’ chemical profiles, show different features between year 0 and year +1 for each sample. This multidisciplinary approach highlights an acclimatization of hop cultivars to the Corsican terroir one year after planting.

Introduction: Determining the bittering profile of hops is a prerequisite for their use in beer making industry. To fully grasp the brewing potential of Corsican hops, it is therefore essential to perform a precise quantification of the molecules responsible for their bittering power. Objective: The aim of this study is highlighting of the bittering profile of Corsican hops. Methodology: A method for the characterization and quantification of α‐acids, β‐acids, and phenolic compounds in Corsican hops using high performance liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) has been developed. In addition to the six α‐ and β‐acids commonly quantified in hops, seven others hop acids were identified using a new methodology based on the analysis of their fragmentation pattern in full‐scan detection mode. The compounds were then quantified as humulone or lupulone equivalents. Subsequently, a metabolomic analysis of hop cones was conducted using the method of molecular networking. Results: A total of 28 compounds were quantified. The influence of both annual climate variations and transplantation on the chemical composition of hops extractives was highlighted. The molecular network elucidation led to the identification of 34 compounds. Among them, eight were previously undescribed in hops, including one previously unknown to the literature. Conclusion: The methodologies developed in this study have shed light on the “bittering” potential of Corsican hops which represents a significant economic opportunity for the local brewing industry potentially establishing a new, sustainable, and profitable hops market. This work focuses extensively on the phenolic compounds and the bittering acids of Corsican hops, aiming to highlight their unique organoleptic characteristics and the influence of the Corsican terroir on their chemical composition and abundance.

Essential oils from wild Corsican hops have never been described before. Following selective harvesting and extraction of plant material, chemical analysis was performed by GC–FID and GC–MS. Subsequent quantitative analysis demonstrated significant inter-stations variability due to pedoclimatic conditions. These singularities produce organoleptic differences, especially within Italian hops, which are the current benchmark for the Mediterranean hops’ population. Corsican wild hops are no exception. Accordingly, three olfactive bouquets were identified by a panel of selected and trained sensory analysts: woody herbaceous ginger notes, herbaceous citrus notes, and common notes. These bouquets appeared to be correlated to pedoclimatic parameters mentioned earlier such as altitude and proximity to the sea. A very rare and appreciated bouquet was associated with high levels of zingiberene in hops growing at moderate altitude and relatively far from the coastline. This study shows the importance of growing sites and pedoclimatic conditions to produce hops with the desired organoleptic notes during the beer making process and provides detailed identification of essential oils from Corsican wild hops.

L’objectif de ce travail de Thèse, à travers une étude morphologique et phytochimique, était de déterminer les caractéristiques brassicoles des houblons poussant spontanément en Corse. Dans cette optique, une stratégie d’échantillonnage, l’étude de la composition chimique, la construction de la première houblonnière de Corse et le renforcement génétique des plants spontanés par hybridation manuelle ont été mis en œuvre en vue de la compréhension de la typicité des houblons insulaires et de l’impact de la mise en culture du terroir corse sur ces différents aspects. Les analyses morphologiques ont démontré (i) une forte influence de la proximité marine de même qu’un impact environnemental et pédoclimatique conséquent sur le polymorphisme du houblon, (ii) un important potentiel d’acclimatation des cultivars étrangers au terroir de Corse. Les analyses phytochimiques par les techniques chromatographiques en phase gazeuse (CPG-SM), d’une part et en phase liquide (CL-SM/SM), d’autre part, ont montré (i) une diversité géographique des huiles essentielles des houblons spontanés et leur typicité régionale par l’abondance du zingibérène aux arômes recherchés dans le monde brassicole, (ii) l’influence des variations climatiques interannuelles sur les fractions lourdes du houblon, (iii) une acclimatation rapide des cultivars étrangers transplantés en Corse, (iv) une influence positive de la mise en culture des houblons spontanés sur leurs teneurs en α-/β-acides et en flavonoïdes, ainsi que (v) une voie de valorisation organoleptique envisageable pour les feuilles et les tiges du végétal, considérées, jusqu’à présent, comme des « déchets de brassage ». Une analyse métabolomique des cônes de houblon a permis l’identification de trente-quatre composés par la méthode innovante dite des « réseaux moléculaires », dont huit encore jamais décrits dans le houblon et un jamais décrit dans la littérature. En ouverture à ce travail, la caractérisation génétique de la biodiversité des houblons a mis en lumière l’origine probable des accessions corses.