Rapid Determination of Bitterness in Beer Using Fluorescence Spectroscopy and Chemometrics

Christensen, Jakob; Ladefoged, Anne Marie; Nørgaard, Lars

doi:10.1002/j.2050-0416.2005.tb00642.x

Cited by 35 publications

(28 citation statements)

References 18 publications

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“…Although fluorescence measurements do not provide detailed structural information, the technique is highly sensitive to changes in the structural and dynamic properties of bimolecular complexes. Some aspects of the technique and applications of fluorescence spectroscopy in food research have been summarized elsewhere [15,16].…”

Section: Fluorescence Spectroscopymentioning

confidence: 99%

Use of spectroscopic data for automation in food processing industry

Ghosh

Jayas

2009

Sens. & Instrumen. Food Qual.

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Advances in spectroscopy now enable researchers to obtain information about chemical and physical components in food or biological materials at the molecular level. Various spectroscopic techniques (e.g., atomic absorption spectroscopy, Raman and Fouriertransform infrared spectroscopy, near infrared spectroscopy, nuclear magnetic resonance spectroscopy, mass spectroscopy, X-ray fluorescence spectroscopy, ultra-violet spectroscopy) have been used to study structure-function relationships in foods (both liquid and solid) to improve overall food quality, safety and sensory characteristics; to investigate fungal infections in plant materials (e.g., fruits, seeds); or to study mobility of different chemical components in food materials. Processing, analyzing, and displaying these data can often be difficult, time-consuming, and problem-specific. Chemometrics is well established for calibrating the spectral data to predict concentrations of constituents of interest. Similarly, proteomics deals with the structure-function relationship of proteins. Since most of the food processing industries are becoming increasingly automated, there is a need to understand how the spectroscopic data can be used for automation. In this paper, we have provided basic working principles of the above mentioned spectroscopic techniques, examples of the use of spectral data in food processing, methods of analysis of spectral data and their integration in the automation process.

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Section: Fluorescence Spectroscopymentioning

confidence: 99%

Use of spectroscopic data for automation in food processing industry

Ghosh

Jayas

2009

Sens. & Instrumen. Food Qual.

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“…The main problem with the spectrophotometric method is that it is not specific since it measures all extracted compounds that absorb at 275 nm, including non-bittering principles 6 . Conversely, adequate HPLC analysis provides reliable information on the nature and the real levels of the bittering principles in beer.…”

Section: Iso-α-acids Profile In Extract (%) Recovery Of Iso-α-acidsmentioning

confidence: 99%

“…The most widely used methodology for beer bitterness determination is based on spectrophotometry, measuring the UV absorption of an iso-octane extract of acidified beer at 275 nm. However, this method is rather unspecific as, next to iso-α-acids, also other beer constituents unrelated to bitterness are extracted and measured 6,24 . Therefore, aiming at more selective determination of the major beer bittering principles, i.e., iso-α-acids, High Performance Liquid Chromatography (HPLC) is increasingly applied.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Quantitative Extraction and HPLC Determination of Hop and Beer Bitter Acids

Jaskula¹,

Goiris²,

Rouck³

et al. 2007

Journal of the Institute of Brewing

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A pleasant and consistent bitterness is an essential flavour attribute of beer. Hop-derived iso-α-acids are largely responsible for beer bitterness and accurate determination of these primary flavour compounds is very important in relation to quality control. The most widely used way to determine beer bitterness is based on spectrophotometry, measuring the absorbance of an iso-octane extract of acidified beer. However, this approach is far from specific as it measures all of the extracted compounds, including non-bittering principles. For that particular reason, High Performance Liquid Chromatography (HPLC) is increasingly applied for the quantitative determination of hop-derived iso-α-acids and, if present, reduced iso-α-acids. However, to obtain accurate data on beer bitterness profiles, both quantitative sample preparation and state-of-the-art HPLC are essential. In this paper, several extraction procedures based on solid phase extraction (SPE) and liquid-liquid extraction (LLE), respectively, were evaluated and an optimised extraction methodology using H 3 PO 4 for sample acidification prior to extraction is presented. The proposed extraction/HPLC methodology allows for the quantitative recovery and analysis of hop-derived beer bitterness.

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“…Sensitization consists of attaching energy-absorbent ligands to the lanthanide ion, which absorb excitation energy and transfer it to the lanthanide element, allowing fluorescence to occur. The sensitizing ligands are typically organic [25]. They act as energy "antennae" to the lanthanide ion and are referred to as "donors", while the lanthanide element that receives the transferred energy is known as the "acceptor".…”

Section: Photoluminescent Methodsmentioning

confidence: 99%

Photoluminescent Detection of Dissolved Underwater Trace Explosives

Langston

2010

The Scientific World JOURNAL

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A portable, rapid, and economical method for in situ trace explosive detection in aqueous solutions was demonstrated using photoluminescence. Using europium/thenoyltrifluoroacetone as the reagent, dissolved nitroglycerin was fluorescently tagged and detected in seawater solutions without sample preparation, drying, or preconcentration. The chemical method was developed in a laboratory setting and demonstrated in a flow-through configuration using lightweight, inexpensive, commercial components by directly injecting the reagents into a continually flowing seawater stream using a small amount of organic solvent (approximately 8% of the total solution). Europium's vulnerability to vibrational fluorescence quenching by water provided the mode of detection. Without nitroglycerin in the seawater solution, the reagent's fluorescence was quenched, but when dissolved nitroglycerin was present, it displaced the water molecules from the europium/thenoyltrifluoroacetone compound and restored fluorescence. This effort focused on developing a seawater sensor, but performance comparisons were made to freshwater. The method was found to perform better in freshwater and it was shown that certain seawater constituents (such as calcium) have an adverse impact. However, the concentrations of these constituents are not expected to vary significantly from the natural seawater used herein.

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Rapid Determination of Bitterness in Beer Using Fluorescence Spectroscopy and Chemometrics

Cited by 35 publications

References 18 publications

Use of spectroscopic data for automation in food processing industry

Use of spectroscopic data for automation in food processing industry

Enhanced Quantitative Extraction and HPLC Determination of Hop and Beer Bitter Acids

Photoluminescent Detection of Dissolved Underwater Trace Explosives

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