On the Analysis of Hop Bitter Acid

Verzele, M.; Dyck, J. Van; Claus, H.

doi:10.1002/j.2050-0416.1980.tb03946.x

Cited by 37 publications

(3 citation statements)

References 9 publications

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“…The development of efficient analytical methods to determine these analytes has been a motivation for analytical chemists across the years. The most widespread technique for α and β‐acids identification and determination in hops is HPLC . However, not all available methods in literature by HPLC allow baseline separation of six α and β‐acids.…”

Section: Introductionmentioning

confidence: 99%

Baseline separation of α and β‐acids homologues and isomers in hop (Humulus lupulus L.) by CD‐MEKC‐UV

et al. 2019

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An alternative method for simultaneous baseline separation of α and β‐acids homologues and isomers in hop by CD‐MEKC with UV detection was proposed. The optimized background electrolyte was composed of 30 mmol/L sodium tetraborate solution, 45 mmol/L sodium dodecyl sulfate, 20 mmol/L β‐cyclodextrin and 10% v/v acetonitrile. The instrumental conditions were evaluated by using a 33 Box‐Benhken experimental design. In order to demonstrate the applicability of the method, 21 hop samples from different varieties were analyzed. The repeatability intra‐ and interday tests were performed and relative standard deviations lower than 7% for area and migration times were observed. The present method comprehended 8 min analysis time and revealed to be faster and more efficient when compared to previous reports from literature.

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Section: Introductionmentioning

confidence: 99%

Baseline separation of α and β‐acids homologues and isomers in hop (Humulus lupulus L.) by CD‐MEKC‐UV

et al. 2019

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“…In the literature, several works dealing with method development for analysis of α and β‐acids in the hops are reported, mainly by high pressure liquid chromatography (HPLC) coupled to ultraviolet/visible , mass spectrometry (MS) detection or both and even with nuclear magnetic resonance (NMR) detector . Alternatively to HPLC, capillary electrophoresis (CE) is also evaluated as an interesting analytical technique for this kind of analysis for providing higher efficiencies, faster separation times, and it requires low sample volumes .…”

Section: Introductionmentioning

confidence: 99%

Capillary electrophoresis in association with chemometrics approach for bitterness hop (Humulus lupulus L.) classification

2018

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The precursor compounds related to the bitterness of beer are called α-acids. These compounds are extracted from the hop, which is an important ingredient in the brewing process. These compounds were analyzed by capillary electrophoresis. The electrophoretic method used 160 mmol/L of ammonium carbonate (pH 9) as BGE (background electrolyte), a voltage of +20 kV in a capillary with 50 μm of internal diameter and with a 62.5 cm of total length (54 cm effective). The samples were injected in hydrodynamic mode applying a pressure of 25 mbar for 5 s and the analytes were detected at 230 nm. A hydromethanolic extraction during 3 h was considered as the optimum condition for the sample preparation using MeOH/H O 80:20 v/v as the extract solution. From the optimized conditions the electropherograms were evaluated for their use as input for chemometric modeling. Preprocessing investigation for electrophoretic data taking into account the alignment, denoising and baseline correction, and variable selection were considered before the chemometric modeling using principal component analysis (PCA). The electrophoretic data were systematically evaluated to find the optimum conditions to modeling. A PCA analysis for all tests was carried out using different preprocessing methods and, an explained variance higher than 90% was achieved in all of them. The optimized chemometric method worked with aligned and meancentered data. From this approach, a simple and efficient method to classify hop samples with high and low α-acids content without the use of analytical standards was established from a simple electrophoretic analysis.

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“…In our first paper [5] on the LC of hop bitter acids, no attempt at quantitation was made. In 1980 a first quantitative LC method for alpha acids with chalkone as internal standard was presented [14]. The adverse effect of trace metals in the chromatographic system, although small, was clearly demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Improved analysis by liquid chromatography of iso‐alpha acids

Verzele

Steenbeke

Verhagen

et al. 1990

J. High Resol. Chromatogr.

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SummaryThis paper shows that the liquid chromatography (LC) methods so far described in the literature for iso-alpha acids analysis are unsatisfactory. The main reasons for this are the failure of the advocated eluent systems to completely suppress trace metal activity of commercial LC columns and the lack of a stable reference iso-alpha acid.The trace metal problem can be solved by using a column packing material specifically designed for "Hop Acid" analysis and by adding ethylenediaminetetraacetate (EDTA) to the eluent.The reference problem is more difficult, but possibly a formulation of the iso-alpha acids in their acid form may be the answer.Chromatographic conditions changing the elution pattern of the individual iso-alpha acids are studied. This leads to better control of their co-elution in the analytical procedure.

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On the Analysis of Hop Bitter Acid

Cited by 37 publications

References 9 publications

Baseline separation of α and β‐acids homologues and isomers in hop (Humulus lupulus L.) by CD‐MEKC‐UV

Baseline separation of α and β‐acids homologues and isomers in hop (Humulus lupulus L.) by CD‐MEKC‐UV

Capillary electrophoresis in association with chemometrics approach for bitterness hop (Humulus lupulus L.) classification

Improved analysis by liquid chromatography of iso‐alpha acids

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