Extraction and analysis of essential oil from Humulus lupulus L. cultivars (hops, Cannabaceae)

Abstract

Humulus lupulus L., also known as hop, is a plant that belongs to the Cannabaceae family and is known throughout the world as a raw material in the brewing industry, as well as its role in the pharmaceutical, nutritional, food and cosmetics industries. Hop female inflorescences form the hop cones, where the lupulin glands are developed, being responsible for the biosynthesis and storage of hop's secondary metabolites. Amongst them, the most economically important are the compounds present in the volatile oils, which contribute to the aroma and flavor of the beer, and the bitter acids, which are responsible for providing the bitter taste, increasing beer conservation and stabilizing its foam. There are many extraction methods for these volatile oils, and their analysis are usually carried out by gas chromatography coupled with flame ionization detector or mass spectrometer.Currently, about 97% of hops grown around the world are destined for beer brewing and it's possible to notice in Brazil a growing trend in beer production in the last years, having the third place in the world ranking. However, most of the hops used in Brazil are still imported. Thus, this research project aims to compare different extraction methods followed by gas chromatography analysis of hops volatile oils from different origins, therefore generating information that will allow the improvement of studies on hops cultivation and quality produced in Brazil, as well as contributing to obtain important data for researches on the plant's volatile oils.