Development of a stir bar sorptive extraction method to study different beer styles volatile profiles.

Compounds with toxic potential may occur in beer, such as carbonyl compounds (acetaldehyde, acrolein, ethyl carbamate [EC] and formaldehyde) and furan derivatives [furfural and furfuryl alcohol (FA)]. The objective of this study was, for the first time, to validate a method based on headspace-solid phase microextraction using a PDMS-overcoated fibre and gas chromatography with mass spectrometric detection in selected ion monitoring mode (HS-SPME-GC/MS-SIM) to investigate target carbonyl compounds and furan derivatives in beers. Analytical curves showed proper linearity with r2 ranging from 0.9731 to 0.9960 for acetaldehyde and EC, respectively. The lowest LOD was found for acetaldehyde (0.03 µg L-1), while the lowest LOQ value (1.0 µg L-1) was found for acetaldehyde and EC, formaldehyde and furfural. Recovery (90% to 105%), intermediate precision and repeatability (lower than 13%), limits of detection and quantification (values below 2.5 μg L-1) showed that the method is suitable to simultaneously quantify these compounds. EC was detected in only two samples (1 lager and 1 ale). Furfural was found in 37% and 82% of ale and lager beers, respectively. Acetaldehyde, acrolein, formaldehyde and FA were detected in all samples. However, acrolein was the only compound found in the commercial samples at a concentration capable of causing health risk. Besides furfural and FA, four other furan-containing compounds (5-methyl-2-furan methanethiol, acetylfuran, 5-methylfurfural and γ-nonalactone) were also found in beers, however, at levels low enough not to impose potential health risk.

Validation of an analytical method using HS-SPME-GC/MS-SIM to assess the exposure risk to carbonyl compounds and furan derivatives through beer consumption

Surface-enhanced Raman spectroscopy (SERS) is an emerging technology that combines Raman spectroscopy and nanotechnology with great potential. This technology can accurately characterize molecular adsorption behavior and molecular structure. Moreover, it can provide rapid and sensitive detection of molecules and trace substances. In practical application, SERS has the advantages of portability, no need for sample pretreatment, rapid analysis, high sensitivity, and ‘fingerprint’ recognition. Thus, it has great potential in food safety detection. Alcoholic beverages have a long history of production in the world. Currently, a variety of popular products have been developed. With the continuous development of the alcoholic beverage industry, simple, on-site, and sensitive detection methods are necessary. In this paper, the basic principle, development history, and research progress of SERS are summarized. In view of the chemical composition, the beneficial and toxic components of alcoholic beverages and the practical application of SERS in alcoholic beverage analysis are reviewed. The feasibility and future development of SERS are also summarized and prospected. This review provides data and reference for the future development of SERS technology and its application in food analysis.

/pdf/recent-developments-in-surface-enhanced-raman-spectroscopy-1xve232z.pdf

Recent Developments in Surface-Enhanced Raman Spectroscopy and Its Application in Food Analysis: Alcoholic Beverages as an Example

Abstract To evaluate the differences in the volatile compound profile of dark and pale beers fermented by different strains of brewer's yeast, gas chromatography with flame ionization detection and gas chromatography mass spectrometry analysis of eight beers was carried out. The prevalent group of compounds in all the beers analysed were alcohols (56.41–72.17%), followed by esters (14.58–20.82%), aldehydes (8.35–20.52%), terpenes and terpenoids (1.22–6.57%) and ketones (0.42–1.00%). The dominant higher alcohols were 2-methylpropan-1-ol, 3-methylbutanol, phenethyl alcohol, among aldehydes furfural, decanal, nonanal, and among esters ethyl acetate, phenylethyl acetate and isoamyl acetate. Beers fermented by the top-fermenting yeast Saccharomyces cerevisiae var. diastaticus had the highest volatile content. The addition of dark malt in wort production process had no effect on the total content of volatiles, but for some beers it caused changes in the total content of esters, terpenes and terpenoids. Variations in the total volatile content between beers fermented by different yeast strains are mainly due to esters and alcohols identified. Sensory analysis of beers allowed us to identify the characteristics affected by the addition of dark speciality malts in the production of wort and yeast strains used in the fermentation process. 

/pdf/evaluation-of-volatile-compound-profiles-and-sensory-el482df5.pdf

Evaluation of volatile compound profiles and sensory properties of dark and pale beers fermented by different strains of brewing yeast

Wine is a complex product containing more than 1000 different types of volatile molecules, of which around 80 may play a relevant role on its sensory characteristics. Aroma active molecules belong to different chemical families, have diverse origins, display a wide range of physicochemical properties, and the levels at which they can be sensory active range from less than 10−9 (2-furfurylthiol) to 102 (ethanol) g/L. Since in order to interpret odor and flavor perceptions all odor-active molecules must be determined, an array of analytical methods able to cope with the previous diversity has to be arranged. The present chapter will address this question. First, potential aroma-active compounds will be listed and classified attending to their “analytical properties” into consistent analytical-groups in order to provide a rationale for the array of instrumental methods to be developed. Secondly, the different alternative instrumental solutions for each category will be discussed.

The Instrumental Analysis of Aroma-Active Compounds for Explaining the Flavor of Red Wines

A simple and fast method was developed for the determination of volatile organic compounds in alcoholic beverages. Eleven volatile organic compounds (acetaldehyde, methanol, 2-propanol, tert-butanol, 1-propanol, ethyl acetate, 2-butanol, isobutanol, 1-butanol, 3-methyl-1butanol, and 2-methyl-1-butanol) in alcoholic beverages were analyzed with a simple direct-injection method using GC with flame ionization detection. These compounds should be monitored in the QC of production processes because they are detrimental to human health. The method was validated with four types of alcoholic beverages (beers, fruit wines, rice wines, and spirits) to confirm the versatility of the method. Linearity showed r2 values from 0.9986 to 0.9995, with LODs ranging from 0.010 to 1.000 mg/L. Precision and accuracy showed acceptable results, proving the effectiveness of the method. The developed method was applied to 40 commercial samples representing the four types of alcoholic beverages, and principal component analysis was performed to determine profiles of the volatile organic compounds, depending on the type of alcoholic beverage.

Simultaneous Determination of Volatile Organic Compounds in Commercial Alcoholic Beverages by Gas Chromatography with Flame Ionization Detection.

한국지질자원연구원(Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350, Korea)요약:경기도 옹진군부근의 근해로부터 채취된 해사로부터 비중 및 자력선별을 통한 중광물의 회수공정을 실시하여, 광물학적 특성을 분석하였다. 옹진군 해사 내에 포함된 중광물로는 티탄철석, 저어콘, 소량의 모나자이트 및 석류석 등이 있으며, 맥석광물로는 석영, K-장석, 사장석, 백운모, 보통각섬석, 녹염석, 녹니석 등이 있다. SIROQUANT 프로그램을 이용한 광물 정량분석 결과, 요동테이블 선별, 영구자석을 이용한 자력선별(rare-earth magnetic separation) 및 전자석 자력선별(Eddy current mag-netic separation)로부터 회수한 유용광물인 티탄철석의 함량은 각각 0.8, 18.3, 48.7%로 증가되었다. 또한 원사, 1차 비중, 2차 비중, 1차 자력 및 2차 자력선별 산물 중 대표시료 및 중광물군에 대한 화학분석치로부터 재계산시, 티탄철석 및 모나자이트의 함량은 각각 0.23, 0.55, 5.22, 16.17, 44.99% 및 0.11, 0.02%, 0.16, 0.51, 1.19%로 증가하였다. 그러나 저어콘의 경우에는 0.13, 0.12, 0.11, 0.15, 0.10%로 큰 변화를 보이지 않았지만, 2차 비중선별시료 중 가장 미립인 -140 메시 입단의 경우 0.27%의 높은 값을 보임으로써 입도분리를 통한 선별 시, 회수율 증대가 기대된다.주요어:중광물, 비중 선별, 자력선별, 광물학적 특성, 정량분석ABSTRACT : Mineralogical study was carried out for heavy minerals in the sea sand near Ongjingun bay, Kyonggi-do separated using the gravity and magnetic separators. Ilmenite, zircon and minor mona-zite and garnet were valuable minerals with gangue minerals of quartz, K-feldspar, plagioclase, musco-vite, hornblende, epidote and chlorite. Quantitative analysis with SIROQUANT program showed that the contents of ilmenite separated with the gravity separation (the shaking table separation), the 1st step magnetic separation (rare earth magnetic separation) and the 2nd step magnetic separation (the Eddy current magnetic separation) were increased into 0.8, 18.3, and 48.7%, respectively. The content of ilmenite, monazite and zircon were recalculated based on the chemical composition of the represen-tative and heavy fraction products of raw sand, the 1 step and 2 step gravity separations, and the 1 step and 2 step magnetic separations. The content increased to 0.23, 0.55, 5.22, 16.17, and 44.99% in ilmenite, 0.11, 0.02, 0.16, 0.51, and 1.19% in monazite. Although the zircon content did not differ over the processes (0.13, 0.12, 0.11, 0.15, and 0.10%), the improved recovery of zircon is expected by applying

https://www.koreascience.kr:443/article/JAKO201117463451344.pdf

Mineralogy of Sea Sand Near Ongjingun through the Separation Processes

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Simultaneous Determination of Volatile Organic Compounds in Commercial Alcoholic Beverages by Gas Chromatography with Flame Ionization Detection.

Mineralogy of Sea Sand Near Ongjingun through the Separation Processes