Identification and Aroma Impact of Volatile Terpenes in Moutai Liquor

Terpenes are very important impact aroma compounds in wines, and we discovered some trace volatile terpenes in Chinese liquors in this study. The volatile compounds in Kweichow Moutai liquor (Maotai) were enriched and isolated by liquid–liquid extraction and further separated by silica gel normal phase chromatography, then investigated by gas chromatography–olfactometry and gas chromatography–mass spectrometry. A total of 55 terpenes were finally identified in Moutai liquor by mass spectrum data from NIST11 a.L and wiley7n.L mass-spectral library, retention indices, and authentic standards. A majority of terpenes were reported in Chinese liquors for the first time. A headspace–solid phase microextraction coupled with gas chromatography–mass spectrometry was developed to determine terpenes in Moutai liquor and other aroma-type Chinese liquors. According to the gas chromatography–olfactometry and odor activity values analysis, terpenes were the important aroma compounds in Moutai liquor which led the liquor more elegant and delicate.     

Quantification of volatile compounds in Chinese soy sauce aroma type liquor by stir bar sorptive extraction and gas chromatography-mass spectrometry

BACKGROUND: Considering the important of aroma compounds on the quality of baijiu, stir bar sorptive extraction (SBSE) coupled with gas chromatography–mass spectrometry was applied to the aromas analysis of baijiu (Chinese liquor). RESULTS: Based on the results of optimization, a total of 76 volatile compounds were identified from 14 Chinese liquors, including 25 esters, 10 alcohols, 9 aldehydes and ketones, 8 aromatic compounds, 5 furans, 3 nitrogen‐containing compounds, 6 acids, 4 phenols, 3 terpenes, 1 sulfide‐containing compound, 1 lactone, and 1 acetal. By principal component analysis based on quantification results, 14 Chinese liquor samples could be classified into three groups. CONCLUSION: SBSE is a fast, simple, effective, and reliable method for extracting volatile compounds from Chinese liquor. The chemometrics approach revealed that LJ liquor with soy sauce aroma could exhibit more prominent sauce flavor through extending the time of storage, and its peculiar manufacturing practice was responsible for the soy sauce flavor. Copyright © 2011 Society of Chemical Industry     

Metabonomics analysis of nonvolatile small molecules of beers during forced ageing

Three kinds of beers with different degrees of ageing were used to examine their nonvolatile small molecules by a metabonomics approach based on ultra performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry (UPLC‐Q‐ToF‐MS/MS). Results showed that a total of 2114 compounds were detected in forced‐aged beers with the positive mode of UPLC‐Q‐ToF‐MS/MS. There was a clear separation among three groups of beers with different degrees of ageing in principal component analysis (PCA) model. Sixteen potential metabolite markers related to beer oxidative stability were identified by orthogonal partial least‐squares discriminate analysis (OPLS‐DA). Results from the changes in the spectrum also indicated that some new compounds formed in beer during forced ageing. Thus, the proposed metabonomics approach is a powerful tool to give a fully understanding the ageing process of beer based on the identification of the markers related to oxidative stability.     

Phosphodiesterase-5 inhibitors in Chinese tonic liquors by liquid chromatography coupled with quadrupole time of flight mass spectrometry

Chinese tonic liquor is an important dietary supplement in daily use, but it often happens that illicitly adulterated drugs in Chinese tonic liquor could lead to food safety issues. In this survey, an analytical method consisting of a liquid chromatography-quadrupole-time of flight mass spectrometer (LC-Q-TOF-MS), coupled with quick easy cheap effective rugged safe (QuEChERS) pretreatment, was established for identification of phosphodiesterase type 5 enzyme (PDE-5) inhibitors in Chinese tonic liquors. 86 PDE-5 inhibitors were qualitatively analysed by employing information dependent acquisition mass spectrometry (IDA-MS) in comparison with the accurate mass of the protonated molecular ion, isotopic pattern, library and chemical formula. This method was used to test 28 Chinese tonic liquor samples. The results revealed that the IDA-MS screening method is suitable for qualitative analysis of 86 PDE-5 inhibitors. Four samples were found to be adulterated with sildenafil, tadalafil, vardenafil, isopiperazinoafil, nortadalafil and desmethylsidenafil, which was 14.3% of the tested samples.     

Simultaneous determination of 15 components in Radix Glehniae by high performance liquid chromatography–electrospray ionization tandem mass spectrometry

A novel qualitative and quantitative method using high performance liquid chromatography coupled with tandem mass spectrometry was developed for simultaneous analysis of 15 components including 10 coumarins, four phenolic acids and adenosine in Radix Glehniae, an important traditional Chinese medicine. The separation was performed on a C₁₈ column with isocratic elution consisted of 0.1% formic acid and methanol (30:70, v/v). The identification and quantification of the analytes were achieved on a hybrid quadrupole linear ion trap mass spectrometer. Multiple-reaction monitoring (MRM) scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. Full validation of the method was carried out (linearity, precision, accuracy, limit of detection and limit of quantification). The results indicated that the method was simple, rapid, specific and reliable. And we successfully applied it to analyze 20 Radix Glehniae samples from different sources.     

白酒风味特征研究进展

白酒作为六大蒸馏酒之一, 有着悠久的历史。白酒酒体风味复杂, 种类多样, 富含多种风味化合物。近年来很多研究者尝试运用风味化学的研究手段解析不同种类白酒的风味成分特征, 从而表征不同工艺、产地白酒产品特征风味的轮廓。本文综述了国产白酒中风味物质研究方法的进展, 概述了萃取、顶空、固相微萃取等样品前处理技术及常用的检测仪器气相色谱质谱(gas chromatography-mass spectrometer, GC-MS)、气相火焰离子化检测器(gas chromatography-flame ionization detector, GC-FID)、全二维气相质谱等在白酒风味研究中的应用进展。并对白酒风味检测与感官品评之间建立的联系和不同香型白酒风味化学的研究成果进行回顾。     

Discrimination of Luzhou‐flavoured fresh raw liquor distilled from Zaopei fermented in new,trend to‐be aged and aged pit mud based on their aroma and flavour compounds

Fresh raw liquors distilled from Zaopei fermented in new, trend to‐be aged and aged pit mud, labelled as N1 and N2, T1 and T2, and A1 and A2, respectively, were analysed by sensory evaluation, two‐dimensional gas chromatography/time‐of‐flight mass spectrometry with combined principal component analysis, gas chromatography–flame ionization detection, liquid chromatography–mass spectrometry with combined hierarchical cluster analysis, and partial least square–discrimination analysis. Results showed that samples had the same grouping situations by each method: the N‐group containing N1 and N2; the T‐group containing T1 and T2; and the A‐group containing A1 and A2. The specific markers for the N‐group liquors were 2‐butanol and butanoic acid, and those for the A‐group were 1‐hexanol, ethyl pentanoate and 2‐pentanone. The threshold contents of 1‐hexanol, ethyl pentanoate, and 2‐pentanone for the A‐group liquors were 1207.95 ± 252.59, 469.89 ± 73.08 and 1105.12 ± 141.91 mg L⁻¹, while those of 2‐butanol and butanoic acid for the N‐group liquors were 215.66 ± 179.50 and 430.65 ± 60.47 mg L⁻¹, respectively. The results from modern chromatographic techniques and chemometric analyses verify the correctness of the traditional sensory evaluation used in controlling the quality of Chinese liquor, contribute to further studies related to the aroma and flavour of Chinese Luzhou‐ flavour of fresh raw liquors and may provide significantly helpful thresholds in distinguishing Chinese Luzhou‐ flavour fresh raw liquors distilled from Zaopei fermented in new, trend to‐be aged and aged pit muds. Copyright © 2017 The Institute of Brewing & Distilling     

Variations in Physicochemical Properties of Chinese Fenjiu During Storage and High-Gravity Technology of Liquor Aging

Gas chromatography, gas chromatography/mass spectrometry, headspace/gas chromatography/mass spectrometry, and Dean's switch technology were used to identify the structure and investigate the transformation of aroma components of Chinese Fenjiu under different ages (from 0 to 30 years). Results showed that the variation in physicochemical properties of Fenjiu was due to the synergistic effects of volatilization of low boiling point matters, oxidation of dissolved oxygen, balance between esterification and hydrolysis, weak interaction among molecules, and involvement of metal elements extracted from storage vessels. By simulating the natural storage environment and utilizing high-gravity rotating packed bed technique, a multistage-spraying rotating packed bed was developed locally and successfully applied to liquor aging. The liquor treated by this method had qualities equivalent to the liquors aged naturally for more than two years. The present study reveals the traditional aging process of Chinese liquor and offers a perspective into the utilitization of high-gravity rotating packed bed technique as an alternative tool for liquor aging.     

Characterization of Aroma Compounds in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) by Gas Chromatography Mass Spectrometry (GC‐MS) and Olfactometry (GC‐O)

Abstract: The aroma‐active compounds in Chinese bayberry were identified using gas chromatography‐olfactometry (GC‐O) and GC‐mass spectrometry techniques. The volatile compounds were extracted using Liquid–liquid extraction, solvent‐assisted flavor evaporation and headspace solid‐phase microextraction (HS‐SPME), respectively. On the basis of odor intensity, the most important aroma compounds in Chinese bayberry samples were caryophyllene, menthol, 4‐terpineol, linalool oxide, linalool, benzyl alcohol, α‐methylbenzyl alcohol, β‐phenylethanol, 3‐methylbutanoic acid and acetic acid, and so on. Moreover, HS‐SPME technique was employed to investigate the aroma compounds among immature and mature waxberry fruits. The results showed that terpenes (for example, β‐caryophyllene) was predominant and its concentration represented over 89.9% of the overall compounds, and alcohols, aldehydes, ketones, esters, acids, and others were typically present in lesser amounts. Finally, principal component analysis revealed that there was also significant difference between immature and mature waxberry fruits     

Volatile compounds characterising Tunisian virgin olive oils: the influence of cultivar

In this work, the volatile profiles of four Tunisian virgin olive oils were established by headspace‐solid phase microextraction and gas chromatography, using flame ionisation and mass spectrometer detectors. More than eighty compounds were isolated and characterised, representing 97–99% of the total GC area. The main volatile compounds present in the oil samples were determined quantitatively, the major constituents were often aldehydes, particularly (E)‐2‐hexenal (48–90%). Significant differences in the content of volatile constituents were observed. These quantitative differences were used to distinguish between virgin olive oils from different varieties.     

Identification of Low Molecular Weight Peptides in Chinese Rice Wine (Huang Jiu) by UPLC‐ESI‐MS/MS

The aim of this work was to increase the general knowledge of peptide identification and to examine the low molecular weight peptides in Chinese rice wine (Huang Jiu) as there are very few publications in the literature on this topic. Chinese rice wine (Huang Jiu) has a high content of peptides and more than 500 peptides have been tentatively identified by ultra‐performance liquid chromatography‐quadrupole time‐of‐flight tandem mass spectrometry (UPLC‐ESI‐MS/MS), including 43 potential bio‐active peptides and 3 sensory‐active peptides, based on published references to date. These peptides have been tentatively identified according to the MS/MS spectra which produced sufficient information of product ions (complementary y ions and b ions). Results from this work indicated that it is feasible to produce rice wine with rich bioactive peptides and that there is potential to examine for rice wine authenticity and traceability based on the origin of the peptides.     

Headspace solid‐phase microextraction analysis of artificial flavors

Using a non‐equilibrated solid‐phase microextraction/gas chromatography/mass spectrometry technique, differentiation between a wide variety of types and examples of artificial flavors has been demonstrated. Addition of an internal standard to the samples, as received, allowed for the calculation of yields on a µg g^?1 basis for the majority of headspace volatiles. The relative standard deviation values expressed as percentages were between 3 and 5%. The precise nature of the approach coupled with the compound identification capacity of the mass spectrometer afforded the capability to easily differentiate between multiple sources of artificial flavors. With a total analysis time of approximately 30 min and the absence of solvent, this approach has the capability of detecting and quantifying the presence of the low‐molecular‐weight solvents often used in the preparation of artificial flavors. Such a capability represents a distinct advantage over more conventional methods of solvent dilution. Results from conventional gas chromatography/mass selective detector analyses are contrasted and compared with the results obtained from the headspace SPME approach. Copyright © 2005 Society of Chemical Industry     

固相微萃取气质联用法测定白酒中的氨基甲酸乙酯

为研究白酒中的氨基甲酸乙酯,采用碱性硅藻土固相萃取+PSA填料过柱方式净化样品,使用气相色谱串联质谱外标法(GC-MS)定量测定白酒中氨基甲酸乙酯的含量。结果表明:在0.085mg/L到1.694mg/L浓度范围内线性相关系数r2为0.9973,线性良好,检出限为2μg/L,回收率在80%~90%之间,具有较好准确度,重复性实验RSD%为3.9,具有良好重现。     

Identification and quantification of lichenysin – a possible source of food poisoning

Lichenysin produced by 53 different Bacillus licheniformis strains has been structurally examined with a qualitative liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using quadrupole-time-of-flight mass spectrometry. The same lichenysin isoforms are produced from all strains, indicating that the growth conditions have a stronger influence on the lipopeptide production than the genotype. A rapid method for the quantification of lichenysin from bacterial cell cultures with LC-MS/MS after a simple methanol extraction has been refined. For the first time commercially available lichenysin has been used as calibrant, making quantification more accurate. The trueness for C15-lichenysin has been improved to 94% using matrix-matched calibration with lichenysin compared with 30% using solvent calibration with surfactin. The quantitative method was fully validated based on Commission Decision 2002/657/EC. The LOD of the method was below 1 µg g^–1 and the repeatability ranged from 10% to 16%.     

Simultaneous Determination of 15 Phenolic Constituents of Chinese Black Rice Wine by HPLC‐MS/MS with SPE

This study established a new method for quantitative and qualitative determination of certain components in black rice wine, a traditional Chinese brewed wine. Specifically, we combined solid‐phase extraction and high‐performance liquid chromatography (HPLC) with triple quadrupole mass spectrometry (MS/MS) to determine 8 phenolic acids, 3 flavonols, and 4 anthocyanins in black rice wine. First, we clean samples with OASIS HLB cartridges and optimized extraction parameters. Next, we performed separation on a SHIM‐PACK XR‐ODS column (I.D. 3.0 mm × 75 mm, 2.2 μm particle size) with a gradient elution of 50% aqueous acetonitrile (V/V) and water, both containing 0.2% formic acid. We used multiple‐reaction monitoring scanning for quantification, with switching electrospray ion source polarity between positive and negative modes in a single chromatographic run. We detected 15 phenolic compounds properly within 38 min under optimized conditions. Limits of detection ranged from 0.008 to 0.030 mg/L, and average recoveries ranged from 60.8 to 103.1% with relative standard deviation ≤8.6%. We validated the method and found it to be sensitive and reliable for quantifying phenolic compounds in rice wine matrices.     

Rapid determination of ethyl carbamate in Chinese rice wine using headspace solid‐phase microextraction and gas chromatography–mass spectrometry

Ethyl carbamate (EC) is a naturally occurring toxic contaminant that may imply a risk to human health and is usually found in alcoholic beverages such as Chinese rice wine. An automated procedure for the rapid determination of EC in Chinese rice wine was developed by headspace solid‐phase microextraction (HS‐SPME) coupled to gas chromatography–mass spectrometry (GC‐MS). Using propyl carbamate as internal standard, the optimized HS‐SPME sampling with a polyacrylic fibre was 45 min at 70°C after applying 38.8% NaCl to saturate the sample. This method showed good linearity over a range of 25–600 µg L^?1 (R² = 0.997). The recovery, relative standard deviation and limit of detection were 90.21–97.35%, lower than 2.89% and 1.19 µg L^?1, respectively. Additionally, the ethanol concentration had no effect on the analysis of EC. The total analysis time of 57 min per sample in continuous determination was twice as fast as the widely used solid‐phase extraction–GC‐MS method. This solvent‐free HS‐SPME‐GC‐MS procedure is suitable for the rapid, automated, and therefore convenient, determination of EC in Chinese rice wine. Copyright © 2012 The Institute of Brewing & Distilling     

Simple determination of formaldehyde in fermented foods by HS‐SPME‐GC/MS

We describe an automatic method to detect formaldehyde (FA) in some fermented foods. This method is based on derivatisation with 2,2,2‐trifluoroethylhydrazine (TFEH) and consecutive headspace solid‐phase micro‐extraction and gas chromatography‐mass spectrometry. FA in food reacted for 30 min at 40 °C with 2,2,2‐TFEH in a headspace vial, and the formed FA‐TFEH derivative was simultaneously vaporised and adsorbed on 85‐μm carboxen–polydimethylsiloxane. Under the established condition, the limit of detection was 0.1 μg kg^?1 by using 1.0‐g solid food and 1.0‐mL liquid food, and the relative standard deviation was less than 10% at FA concentrations between 0.050 and 0.500 mg kg^?1. The concentrations of FA in several traditional Korean foods including gimchi, watery radish gimchi, soybean paste, red pepper paste, soy sauce and bean‐paste soup were measured. All food samples had detectable levels of FA (0.104–13.05 mg kg^?1).     

Polyphenol and volatile profiles of pomegranate (Punica granatum L.) fruit extracts and liquors

This work reports on the preparation of new aromatic pomegranate liquors by maceration of pomegranate juice and arils in Arbutus unedo L. distillate. The volatile, anthocyanin and ellagitannin profiles were monitored after each step. Aromatic compounds of pomegranates, such as limonene, 1‐hexenol and trans‐caryophyllene, were detected in trace levels and showed little contribution to the liquor aroma. The main volatiles of the liquors, namely isobutanol, isopentanols, vitispiranes and volatile esters, are given by the fruit distillate. The anthocyanin contents of the pomegranate juice were around 135 mg L^?1 but decreased to about 5% of this value in the final liquors. Anthocyanin diglucoside compounds showed higher stability than their monoglucoside analogs. Punicalagins and punicalins showed contents between 80 and 135 mg L^?1, depending on the used starting pomegranate material. These ellagitannins account for 60% of the total polyphenols. The procedure can be used to prepare aromatic pomegranate liquors with high polyphenol content.     

固相萃取结合气相色谱-质谱技术定量白酒中的γ-内酯

γ-内酯是食品中的一类重要风味化合物,存在于水果、葡萄酒及白酒等多种食品中。该研究通过液液萃取及固相萃取(SPE)方法,结合气相色谱-质谱(GC-MS),分别定性、定量了白酒中的8种γ-内酯。该定量方法快速,选择性强,对白酒中各内酯均有较好的线性(R2≥0.9908,γ-十二内酯),检出限范围为0.22(γ-癸内酯)～4.30μg/L(γ-壬内酯),低于各内酯的阈值,对不同香型成品酒及原酒的重现性均较好(RSD<15%),可用于白酒中微量成分γ-内酯的快速分析测定。     

Rapid Analysis of Flavor Volatiles in Apple Wine Using Headspace Solid‐Phase Microextraction

Flavor volatiles are important components of alcoholic beverages. In this study, headspace solid‐phase microextraction and gas chromatography—mass spectrometry (HS‐SPME‐GC‐MS) were investigated for the determination of flavor‐contributing volatiles for apple wine. HS‐SPME parameters were defined, including fiber coatings, extraction time, and extraction temperature. Good linearity, recoveries, and repeatability of the SPME method using carboxen‐polydimethylsiloxane (carboxen‐PDMS) fiber were obtained with r² values, recoveries, and relative standard deviations ranging from 0.9112 to 0.9960, 80.23% to 110.21%, and 1.5% to 6.4% respectively using standard solution. No significant effects of ethanol concentration on headspace concentrations of analytes were observed when ethanol concentration changed from 0% to 12% (v/v), indicating that the HS‐SPME‐GC‐MS method can be used for the determination of flavor volatiles in apple wine with an alcohol content below 12% (v/v) as well as in apple juice, and the method enables the monitoring of volatiles in mash during fermentation.