Development of a green, fast and inexpensive procedure for the extraction of fixed and volatile compounds from inflorescences, leaves and branches of Humulus lupulus L. (Cannabaceae)

Abstract

The Brazilian brewing industry moved 77 billion of reais last year, which represents 2% of GDP. Hop availability and quality is the bottleneck of the national brewing industry, which imports approximately 2,400 tonnes per year of hop inflorescences at a cost of about 139 million of reais. In general, hops imported by Brazil are considered of low quality, already devoid of some of the compounds responsible for their sweetening and antioxidant properties (alpha and beta acids, aromatic compounds and xanthohumol). This has stimulated research aimed at adapting this culture to Brazil, including to São Paulo. FCA/UNESP host two of these initiatives, which need support to measure the quality of hops produced from these sweetening compounds. Currently, there is no extraction method that extracts the fixed and volatile compounds from hop inflorescences simultaneously, and the analytical methods advocated by the international brewery associations employ solvents and polluting techniques. Moreover, the imminent rise in hop cultivation scales in Brazil asks what to do with crop byproducts, such as the leaves and branches of the plant. The present work aims to develop an efficient, inexpensive and low environmental impact analytical procedure when compared to reference methods for the simultaneous extraction of fixed and volatile compounds responsible for the sweetening properties of hops produced at FCA/UNESP, followed by their quantifications. It also aims to compare the chromatographic profiles of plant parts that are not commercialized, such as its leaves and stems (thus, can be considered as by-products or residues), with the inflorescences (product), by ultra-high performance liquid chromatography coupled to UV/Vis and mass spectrometry and gas chromatography coupled to mass spectrometry. (AU)