Investigation of applying calcium oxide for the removal of bitter substances from hop wastes

Utilization of brewery wastes is one of the solutions for the production of the fodder supplements containing biogenic nutrients. The condition of such application is to meet the requirements included in the regulations regarding animal feeding, particularly removing a bitter taste. The aim of the performed investigations was the removal of bitter acids from the post-extraction hop waste using the calcium oxide addition. For the examination hop wastes obtained as a by-product from the CO₂ plant extraction in supercritical conditions, were applied. Physicochemical properties of the waste samples collected for the investigations were determined by applying the available standard analytical techniques. The analyses of the determination of bitter acids were carried out by the high performance liquid chromatography method. During the experiments very good effects of bitter acids removal from hop wastes, were obtained by using CaO suspensions in water. The investigations on the influence of the CaO concentration in suspension on the efficiency of bitter acids removal indicate the possibility of applying suspensions by 2 wt% for this purpose.