Characterization of two varieties of Patagonian Hops

C.M. VAN BAREN; P. DI LEO LIRA; D. RETTA; A. TROCHINE; J. BURINI; G. REINER; D. LIBKIND; B. GASTALDI; F. SILVA SOFRÁS; S. GONZÁLEZ; A. BANDONI

Niza

Simposio; 47 th International Symposium on Essential Oils (ISEO2016); 2016

Institut de Chimie de Nice

Hops flowers are used as ingredients in brewing to contribute to the bitterness and flavour. The main chemical components responsible for the aroma (and partly for the flavour) are part of the essential oils contained in the lupulin glands and the content of α-acids. The yield and chemical composition of essential oils may vary for different varieties of cultivar and because of external influences on the hop plant. Nowadays, new aromatic profiles in hops are prized as a way to produce novel types of beer. In Argentina, ?Nugget? is a variety characterized among the bitter ones (high humulones) and ?Cascade? is more aromatic than bitter. For this reason, the volatile components of these varieties of hop cultivated in ?El Bolsón? in the Patagonia, Argentina, were isolated by hydrodistillation and analyzed by GC-FID-MS. In addition, determination of α and β acids, as well as the α/β ratio and the HSI (Hops Storage Index) were done following the ASBC Methods. Besides, performance data comparing "flowers" and "pellets" for each variety is presented.Essential oil yields were higher for the variety ?Nugget? and always higher for flowers than for pellets. The overall volatile composition of the ?Cascade? and ?Nugget? varieties tested were similar to those found in other regions where it is cultivated, as USA and Spain. However, components as geranyl acetate, cis-α-bergamotene, neryl isobutanoate and E--farnesene were detected in larger percentages or exclusively in the ?Cascade? variety; meanwhile, methyl nonanoate, 2-tridecanone and 4,7(11)-amorphadiene were only present inthe ?Nugget? variety . Values of α-acids in ?Cascade? were greater than for other producing regions, like USA or New Zealand, though the α/β ratio obtained is greater with a value of 1.5 for the Patagonian variety regarding the 0.9-1.1 reported. Meanwhile, the α and β acids values for the Patagonian ?Nugget?, as well as the α/β ratio, were similar to those reported for other producing regions (between 11-15% w/w). By comparing the hop flowers with pellets, values of α and β-acids were lower for pellets.A complete comparative discussion about the values obtained in these Patagonian hopsreferred to other producing regions, is given.