Analysis of supercritical carbon dioxide extracts from cones and leaves of a Humulus lupulus L cultivar

Abstract

Extracts obtained by supercritical carbon dioxide extraction of cones and leaves of hop (Humulus lupulus L ) at different combinations of temperature and pressure were analysed for their a-and /I-acids and volatiles, using HPLC and GC respectively. The yield and composition of the mixtures of bitter compounds from the cones were largely influenced by the temperature and pressure applied during the extraction. Bitter compounds could not be detected in the extracts from the leaves. The most important volatile components identified were b-myrcene, /I-caryophyllene and a-humulene. The extraction parameters also influenced the composition of the mixture of volatiles from the cones and leaves, 40°C and 20.0 MPa being optimum for the extraction of both bitter compounds and volatiles, which are thought to be important for the aroma of beer.

Supercritical CO2 extraction of Chilean hop (Humulus lupulus) ecotypes

“…As the temperature is increased above 40 • C, thermal damage may occur, and a reduction in apparent solubility occurs for pressures below 200 bar (cf Fig 2). Langezaal et al 9 proposed that the best conditions to extract essential oils and soft resins simultaneously from hops were also 40 • C and 200 bar (their experimental region was 40-60 • C and 123-271 bar). Hubert and Vitzthum 18 reported that SC-CO 2 extraction at 40 • C keeps hop aroma unchanged, and avoids oxidative reactions as well as isomerization of α-acids.…”

“…Essential oil composition was determined using the gas chromatography-mass spectrometry (GC-MS) test proposed by Langezaal et al 9 Solutions having 1 g dm −3 oleoresin/solution were prepared as indicated previously. A Hewlett Packard 6890 Series GC/MS System (Agilent Technologies, Palo Alto, CA, USA) equipped with a BP-1 capillary column (L = 50 m, φ = 0.22 mm; film thickness = 1 µm) from SGE (Ringwood, Victoria, Australia) was employed.…”

Comparative Gas Chromatographic–Mass Spectrometric Evaluation of Hop (Humulus lupulus L.) Essential Oils and Extracts Obtained Using Different Sample Preparation Methods

“…Next extraction method, accelerated solvent extraction (ASE) was successfully used for the extraction of bitter acids from hops and hop products (Čulík et al 2009). SFE method is suitable for extraction of volatile and nonvolatile compounds of hops including essential oils and hops bitter acids (Langezaal et al 1990;Dzingelevičius et al 2011). The composition of extract obtained using supercritical CO 2 is highly dependent on the temperature and pressure used for extraction.…”

Initiation and growth characterization of some hop cell suspension cultures

“…Subsequently the chloroform layer was concentrated using a rotatory evaporator until evaporation of the solvent was completed. The residue was dissolved in 1.0ml of a methanolic solution of the pnitroanilide of myristic acid (internal standard; 1.32mgml-l), and analysed by HPLC as described previously (Langezaal et al 1990). …”