Determination of Alpha Acids in Humulus japonicas

Abstract

Humulus lupus (hops) is a plant used by the brewing industry to produce alpha acids; organic acids which contribute to the bitter taste of beer. This project sought to extract and quantify the types and amounts of alpha acids present in the invasive species Humulus japonicas (Japanese hops) to determine whether Humulus japonicas is a practical source of alpha acids. To accomplish this goal, an HPLC method was designed to separate the alpha acids present in Humulus lupus. Alpha acids were extracted from ICE-3, a calibrated hops standard, and HPLC was used to isolate 6 compounds. These compounds were quantified and characterized using 1H NMR, UV-VIS, and GC-MS. Then alpha acids were extracted from Humulus japonicas, separated via HPLC, and the isolated compounds were identified using 1H NMR, UV-VIS, and GC-MS. The alpha acids isolated from Humulus japonicas were quantified and compared to standard values to determine if Humulus japonicas is a viable source of alpha acids. The use of Humulus japonicas in beer brewing would allow the brewing industry to utilize an invasive species that is hardy in a wide variety of environments.