2019 ASHS Annual Conference

Three main groups of phytochemicals of value in hop (Humulus lupulus) cones: bittering acids and essential oils are of great interest to the brewing industry, and polyphenols (particularly xanthohumol) are of interest as a nutraceutical. The majority of commercial hops dominating the brewing industry originate from European plant varieties and thrive in a specific geographic location between 45-50° north latitude. H. lupulus neomexicanus is found at lower latitudes native to the Southwest Rocky Mountain region of the United States and is receiving recent attention with the rise of unique craft beer flavors and interest in nutraceuticals. Standard analysis of bittering acids and essential oils in H. lupulus neomexicanus hop varieties using American Society of Brewing Chemists (ASBC) methods revealed a wide range of bittering acid concentrations, but also consistently distinct essential oil profiles when compared to industry standard varieties. Presence of terpenes, rarely found in standard commercial hops, were abundant in H. lupulus neomexicanus varieties. While the essential oil profiles exhibited the presence of unique compounds, the total oil yield was less than 0.2 mL in all neomexicanus varieties due to hermaphroditic properties. Although the ASBC has released early research into hop polyphenols, they have not published a standard method for the extraction and characterization of polyphenols from hops. After comparing multiple published methods, an optimal ethanol extraction procedure was chosen that consistently yielded the highest total phenolic content (TPC) in extracts from standard and neomexicanus hops samples. H. lupulus neomexicanus extracts were consistently higher in total phenolic content (50-100mgGAE/g hops) than published literature values for standard hop varieties (2-50 mgGAE/g hops). Since xanthohumol is the most abundant phenolic compound in hops, a high TPC indicates the potential value of neomexicanus varieties as rich sources of xanthohumol. Because New Mexico is an agricultural state, identifying the potential of native and specialty crops grown in this region could help sustain agriculture in a multitude of downstream markets. The combination of the unique essential oils and high polyphenol concentrations create a potential niche market for Humulus lupulus neomexicanus production in the state of New Mexico, positioning the state to take advantage of expanding intrigue in this rarely used hops.