Determination of bitter acids in South Island grown hops by UPLC : A Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University

Abstract

In this study, ultra-performance liquid chromatography was used to quantify the content of alpha acids in hops grown in Nelson, Canterbury and Southland. This method used a binary solvent system consisting of (1) 100% methanol (A) and (2) 85% of solvent A and 15% of solvent B. B is 0.17% v/v formic acid and water. Analysis was performed isocratically at a flowrate of 0.2 mL/min. Separation was achieved on the column of Acquity UPLC® BEH C18, 50 x 2.1 mm, with a particle size of 1.7μm, and with a Acquity UPLC® BEH C18 1.7μm, VanGuard™ pre-column 5 x 2.1 mm. The compounds of interest eluted within 4 mins. The results of this experimental study show that the content of alpha acids in hops is not only related to the growth environment but also related to the variety.