ABEO-ISO-α-ACIDS

Abstract

During boiling, substantial amounts of hop α‐acids are transformed into oxidation products containing the same cyclopentane nucleus as the iso‐α‐acids: these oxidation products, which have been called abeo‐iso‐α‐acids I, II and III, are separable by countercurrent distribution. Lager beers contained between 88 and 160 mg. of abeo‐iso‐α‐acids per litre. Although the abeo‐iso‐α‐acids are almost devoid of bitterness, they have strong foam‐producing properties.

Composition of Bitter Substances of Hops and Characteristics of Beer Bitterness

“…Besides the well-known compounds, a-acids, iso-a-acids, and hulupones, many new components such as lupoxes a, b, and c (5,8), lupdoxes a and b (5,8), lupdeps (9), and lupdols (9) which cause beer bitterness have subsequently been isolated and characterized. Recently, we confirmed by ion-exchange chromatography that the compounds reported by Ashurst and Elvidge (2), Verzele and Vanhoey (11), Connet and Elvidge (3), Laws and McGuinness(IO), and Howard and Slater (4) were also included among these 90 components 2 , and most of the major bitter components of beer have now been characterized. Therefore, based on these findings we attempted to establish a new technique for evaluating beer bitterness, and we propose a new concept, "the constitution of beer bitterness," for evaluating beer bitterness.…”