Analysis and prognosis of bitter acids content in Czech hop varieties - year 2018 and long-term comparisons and trends

Abstract

This article presents the results of the harvest forecast of the alpha- and beta-bitter acids of the Czech hop varieties in the 2018 harvest, the results are discussed in relation to the long-term averages, the composition of the bitter acid analogs and the stability of the varietal characteristics. 180 hop samples were analyzed using EBC 7.7 (HPLC) method. The alpha-acid content of the most important Saaz variety (2.9% in dry matter) was identical to the 2017 harvest and 18% rel. lower than the 26-year average. The alpha-acid content of Sladek (5.0%), Premiant (4.8%), and Saaz Late (1.6%) varieties was significantly lower than the long-term average. The harvest of the hops of the Kazbek and Agnus varieties was close to the long-term average. The ratio of alpha- and beta-acids, the relative content of cohumulone and the relative content of colupulone were consistent with long-term averages for the tested varieties. It was confirmed, that the harvest forecast gives timely information on the alpha-acids content of the harvest, the results were in good agreement with the values of the final evaluation of all harvested hops samples.

Varietal specificity of polyphenols, free phenolics and antioxidant potential in hops

“…The relative standard deviation of the content of polyphenols within the varieties varied in the range of about 6% to 20%. The variability of polyphenols is thus comparable to that of alpha acids (Mikyška and Jurková, 2019). The least significant factor in the monitored years was the harvest year.…”