固相微萃取及其在食品分析中的应用

固相微萃取 (SPME)是在固相萃取 (SPE)的基础上发展起来的新型萃取分离技术。该技术集采样、萃取、浓缩、进样于一体 ,简便、快速、经济安全、无溶剂、选择性好且灵敏度高。文中介绍了固相微萃取的装置、原理、操作 ,论述了其工作条件选择及优化以及在食品分析中的应用 ,并对其前景进行了展望。     

Determination of flavour compounds in beer using stir‐bar sorptive extraction and solid‐phase microextraction

The analysis of volatile compounds in beer is important for quality control in the brewing industry. In this study, stir‐bar sorptive extraction (SBSE) and solid‐phase microextraction (SPME), two solvent‐less enrichment techniques, were applied in combination with gas chromatography flame ionization detection (GC/FID) for the determination of four flavour compounds (isoamyl acetate, ethyl hexanoate, benzaldehyde, myrcene) in beer. Limits of detection, linearity and repeatability of both methods were determined using standard ethanol solutions, while accuracy was determined by conducting recovery tests on commercial beer samples. Both methods were characterized by high linearity (r > 0.996) and repeatability (RSD = 1.76–10.66%). When both methods were compared, higher recoveries were obtained by SBSE, with limits of detection 1.8–2.8 times lower compared with SPME. In the analysis of commercial beer samples using both methods, SBSE analysis resulted in higher recoveries, therefore demonstrating promise for the analysis of beer volatiles. Copyright © 2015 The Institute of Brewing & Distilling     

Simultaneous headspace solid phase microextraction analysis of off‐flavour compounds from Quercus suber L. cork

A headspace solid phase microextraction/gas chromatography/(ion trap) mass spectrometry (HS‐SPME/GC/MS) method was developed for the simultaneous analysis of volatile compounds responsible for off‐flavours in cork‐stoppered wines, namely 3‐methyl‐1‐butanol (3MB), 1‐octen‐3‐ol (OCT3), 1‐octanol (1OCT), guaiacol (GUA), 2‐methylisoborneol (MIB), 2,4,6‐trichloroanisole (TCA) and geosmine (GEO). Extraction temperature, global linearity and linearity, reproducibility and repeatability of each chemical were optimised and interference effects were studied. The optimisation studies showed that an extraction temperature of 30 °C gave the best reproducibility and linearity. The global chromatographic areas were linearly correlated (R² = 0.9788) with the global matrix concentration between 41.5 and 275.2 mg L^?1. The reproducibility and linearity of the studied HS‐SPME methodology indicated coefficients of variation between 3.2 and 8.8% and linear responses to all compounds, with regression coefficients (R²) between 0.9516 and 0.9886. Finally, it has been observed that variation of the concentration of 1OCT causes significant variation in the chromatographic areas of the other compounds, with the exception of OCT3. Therefore, if 1OCT is detected at a level that potentially causes interferences in quantification of the other components, new calibration curves must be prepared incorporating an appropriate background concentration of this component. Copyright © 2007 Society of Chemical Industry     

顶空-固相微萃取与气质联用法分析草菇中的香味成分

本文以享有“中国蘑菇”之称的草菇为原料，采用碳分子筛-聚二甲基硅氧烷（CAR／PDMS）涂层的固相微萃取头分别萃取新鲜草菇和干草菇蒸馏后的挥发性成分，并通过气质联用仪分析鉴定了其主要的香味成分。结果表明，固相微萃取有效地吸附了草菇中的挥发性成分，经NIST质谱数据库和文献对照，分别从干草菇和新鲜草菇中检测出48和29种成分，其中八碳化合物是最要的风味主体。     

Screening and distinction of coffee brews based on headspace solid phase microextraction/gas chromatography/principal component analysis

The volatile profiles of espresso and plunger (cafetière) coffees prepared from (1) an 80:20 (w/w) blend of natural roasted Robusta and Arabica (Robusta Natural blend), (2) a 40:40:20 (w/w/w) blend of Robusta Natural blend, Robusta torrefacto roast (850 g kg^?1 Robusta, 150 g kg^?1 sugar) and (3) natural roasted pure Arabica were established by headspace solid phase microextraction (SPME) after selection of the fibre coating (polyacrylate or polydimethylsiloxane) and the temperature and time of extraction. For the analysis of furans and indoles the polyacrylate coating proved to be more suitable; however, for the overall characterisation of the volatile composition of espresso and plunger coffees the polydimethylsiloxane coating was chosen. SPME/gas chromatography (GC)/mass spectrometry (MS) analyses allowed the identification of 37 compounds: four aldehydes, two ketones, 11 furans, 10 pyrazines, two pyridines, three phenolic compounds, two indoles, one lactone, one ester and one benzothiazine. The volatile composition was related more to the botanical variety (Arabica or Robusta) than to the method of preparation of the brew (espresso or plunger). Furthermore, use of the variability provided solely by the GC peak areas and respective retention times, combined with principal component analysis (PCA), yielded the information necessary for discrimination. The combined technique of headspace SPME/GC/PCA, as an alternative to conventional techniques based on GC/MS, is proposed as a lower‐cost, fast and reliable technique for the screening and distinction of coffee brews. Copyright © 2003 Society of Chemical Industry     

苦味UHT乳原因分析

通过对发生苦味的UHT乳进行分析，将引起UHT乳贮存中出现苦味的原因分为两大类：一是受残留的微生物污染导致UHT乳产生苦味和其它异味，这类微生物包括耐热性强的解淀粉芽孢杆菌和青霉菌等；二是由于牛乳中存在的水解酶分解蛋白质和脂肪．生成肽、氨基酸和脂肪酸类，导致苦味的出现。针对这些影响因素，可以通过提高原料乳的卫生质量、严格控制生产加工过程和环境卫生，以避免UHTSL出现苦味的质量问题。     

Analysis of brandy aroma by solid‐phase microextraction and liquid–liquid extraction

Headspace solid‐phase microextraction (SPME) and continuous liquid–liquid extraction (LLX) with Freon were used to extract and analyse aroma volatiles in brandy. In general, SPME using a non‐polar polydimethylsiloxane coating was more selective for esters and acids than was LLX. LLX using Freon 11 extracted the higher alcohols more efficiently than SPME. Relative differences in volatiles between brandies made from Vitis vinifera L cv Colombard and Vitis vinifera L cv Ugni blanc were observed, particularly for hexanol, 3‐methylbutylacetate, 3‐methylbutanol and 3‐methylbutyloctanoate. In addition, a combination of SPME with GC–olfactometry was used to provide more detailed information on sensory characteristics of varietal brandies. © 2000 Society of Chemical Industry     

固相微萃取法分析凤凰单枞乌龙茶香气组分

本文以凤凰单枞乌龙茶（Camellia sinensis）为材料，采用固相微萃取（solid Phase Microextraction，SPME）对其呈香组分进行研究。结果表明采用SPME萃取凤凰单枞乌龙茶香气组分，从桂花香型乌龙茶干茶样中检测出41种香气组分，而SDE法则检测到55种香气组分，两种方法都检测出高比例的芳樟醇、橙花叔醇、茉莉酸甲酯和吲哚。SPME法萃取了乌龙茶自身散发出的香气组分，避免了茶叶中易挥发或热不稳定的香气组分被破坏，减少了香气组分的测定误差和不稳定性。     

不同体细胞数原料乳对UHT贮存期间蛋白和脂肪水解的影响

不同体细胞数(21.4×104mL-1,75.8×104mL-1,118.1×104mL-1和216.2×104mL-1)原料乳生产的4组UHT乳在37℃贮存84d,对其贮存期间的蛋白水解及脂肪水解进行研究。结果表明,4组UHT乳贮存期间的蛋白水解速率无显著性差异(P>0.05),原料乳体细胞数并未对蛋白水解造成影响;4组UHT乳贮存期间的脂肪水解速率具有显著性差异(P<0.005),原料乳体细胞数与脂肪水解速率间存在极明显的正相关(R=0.9886,P<0.05)。     

固相微萃取技术(SPME)分析羊奶中挥发性化合物

采用固相微萃取技术（SPME）提取羊奶中的挥发性化合物,经气相色谱质谱联用仪进行测定分析,实验结果表明,羊奶中挥发性化合物共检测到42种,主要成分为挥发性脂肪酸,酯类、醇和酮类,还含有一些其他挥发性化合物。其中挥发性脂肪酸有10种,主要由短链脂肪酸和中等长度碳链脂肪酸组成。酯类物质有16种,主要包括邻苯二甲酸二丁酯、邻苯二甲酸二乙酯、14-甲基-十五酸甲酯和己二酸二（2-乙基）乙酯等。另外挥发性醇类和酮类物质共7种,其它挥发性化合物9种。      

Monitoring the authenticity of Brazilian UHT milk: A chemometric approach

In this work, chemometric methods are reported as potential tools for monitoring the authenticity of Brazilian ultra-high temperature (UHT) milk processed in industrial plants located in different regions of the country. A total of 100 samples were submitted to the qualitative analysis of adulterants such as starch, chlorine, formol, hydrogen peroxide and urine. Except for starch, all the samples reported, at least, the presence of one adulterant. The use of chemometric methodologies such as the Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) enabled the verification of the occurrence of certain adulterations in specific regions. The proposed multivariate approaches may allow the sanitary agency authorities to optimise materials, human and financial resources, as they associate the occurrence of adulterations to the geographical location of the industrial plants.     

Analysis of the headspace volatiles of freshly brewed arabica coffee using solid-phase microextraction

ABSTRACT:  Headspace volatiles of freshly brewed drip coffee were investigated by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/olfactometry (GC/O, CharmAnalysis™) analyses. For this purpose, a solid-phase microextraction (SPME) sampling method for the headspace volatiles of freshly brewed drip coffee was developed. SPME fiber coated with divinylbenzene (DVB)/carboxen/polydimethylsiloxane (PDMS) was selected from 6 types, and sampling time was determined at 2 min. The headspace coffee volatiles stayed constant in proportion for the first 2 min to keep the freshness of the brewed coffee aroma. Using this sampling method, the headspace volatiles of freshly brewed drip coffee (Ethiopian arabica coffee, roast degree: L value; 23) were examined by GC/MS and GC/O analyses. From the GC/O results, 1-(3,4-dihydro-2 H -pyrrol-2-yl)-ethanone (nutty-roast odor) and 4-(4'-hydroxyphenyl)-2-butanone (raspberry ketone, sweet-fruity odor) were newly detected as components in the aroma of coffee.     

普洱熟茶香气成分的顶空固相微萃取条件优化

目的优化普洱熟茶香气成分顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)-气质联用的萃取条件。方法利用Box-Benhnken的中心组合实验设计原理,以香气物质的质谱图峰面积为考察指标,对水/茶比、萃取温度、萃取时间进行3因素3水平响应面分析。结果萃取时间、萃取温度、萃取时间-萃取温度、水茶比的二次项和萃取温度的二次项对普洱茶中香气成分提取有显著影响(P0.05),而其他几项影响不显著。利用Design-Expert 8.0软件,对数据分析后,得到最优条件为水/茶比为9.76、萃取时间2.47 h、萃取温度76.64℃。结论在优化的条件下,香气物质峰面积可达到理论上的最大值是5.48×10~8。     

顶空固相微萃取-气质联用技术分析秘鲁鱿鱼肉的挥发性风味成分

采用顶空固相微萃取-气质联用技术(SPME-GC/MS)分析检测了秘鲁鱿鱼肉不同部分的挥发性风味成分。结果表明:烃类物质含量最多,在肉中呈对称分布;醇类、酮类物质主要分布在肉的内侧;而秘鲁鱿鱼肉中的杂环化合物及酯类物质分布较均匀,对肉品风味主要贡献芳香味。杂环化合物主要为吡嗪类物质,酯类主要为乙酸乙酯。另外,乙酸和N,N-二甲基甲酰胺及二甲胺对秘鲁鱿鱼肉产生"怪酸"味起主要作用,且这两种物质在肉中的分布均符合中间含量多、两边含量少的规律。     

不同等级菜籽油中挥发性气味物质检测的 顶空固相微萃取条件优化及鉴定

采用顶空固相微萃取-气相色谱质谱法测定不同等级菜籽油中的挥发性气味物质。以总峰面积和出峰数量为指标,采用单因素实验对顶空固相微萃取条件(萃取头、萃取温度、吸附时间、解吸时间）进行优化,并在最优条件下对一级、三级、四级菜籽油的挥发性气味物质进行鉴定。结果表明：检测菜籽油中挥发性气味物质的最优顶空固相微萃取条件为采用50/30 μm CAR/DVB/PDMS萃取头、萃取温度75 ℃、吸附时间30 min、解吸时间2 min,在此条件下经过GC-MS检测出的菜籽油挥发性气味物质成分最多,总峰面积最大。在最优萃取条件下测得一级、三级、四级菜籽油中挥发性气味物质分别有11、17、25种,其中一级菜籽油的主要挥发性气味物质为醛类,占57.94%;三级、四级菜籽油的主要挥发性气味物质为硫甙降解产物和杂环类物质,分别占37.33%、50.52%和17.50%、25.90%。     

烤制鹌鹑蛋挥发性成分SPME条件优化

以鹌鹑蛋为原材料,研究了烤制鹌鹑蛋挥发性成分的固相微萃取(SPME)条件。通过单因素和正交实验对萃取头种类、样品萃取量、萃取时间、萃取温度以及解吸时间进行优化。结果表明,较佳的萃取条件为:DVB/CAR/PDMS萃取头,萃取时间为30min,萃取温度为65℃,样品萃取量为2g,解析时间为2min。在此条件下,检测到烤制鹌鹑蛋中的挥发性成分34种。      

低盐鱼酱油挥发性成分的固相微萃取和气相色谱-质谱法分析

用固相微萃取装置(SPME)萃取鱿鱼废弃物低盐鱼酱油的挥发性成分,利用气相色谱-质谱联用仪(GC-MS)对挥发性化合物成分进行了检测和定性分析。结果表明,鱿鱼废弃物低盐鱼酱油的挥发性成分有91种,包括7种酸、5种醇类化合物、26种羰基化合物、4种酯类化合物、18种含氮化合物、14种含硫化合物、5种呋喃类化合物、5种酚类化合物、7种碳氢类化合物,共同构成了鱼酱油的特殊风味。同时根据峰面积百分比可以初步推断,苯基乙醇、2-甲基丁醛、苯甲醛、苯乙醛、安息香酸乙酯、2-二甲氧基-苯酚、2-甲氧基-4-乙烯基苯酚、2-乙基呋喃、二甲基三硫化物、二甲基二硫化物、3-苯基呋喃、2-乙基-6-甲基吡嗪是鱿鱼加工废弃物低盐鱼酱油的主要挥发性化合物。     

原料乳中体细胞数与UHT乳中酪蛋白成分的关系研究

研究了原料乳中体细胞数与15批次UHT乳样本中酪蛋白成分之间的关系。将原料乳巴氏杀菌后进行超高温处理。分别于8,30,60,90和120 d采集贮藏于室温条件下的UHT乳样本,并使用高效液相色谱法对酪蛋白成分进行分析。体细胞数范围1.97×105～8×105 mL-1。体细胞数与原料乳或UHT乳中的κ-酪蛋白质量浓度之间没有相关性(P<0.05)。原料乳中αs2-酪蛋白和β-酪蛋白与体细胞数呈负相关(P<0.05)。UHT乳中,αs1-酪蛋白(P<0.05)和β-酪蛋白(P<0.05)与体细胞数在贮藏第8天呈负相关,αs2-(P<0.01)与体细胞数在贮藏第60天呈负相关。结果表明,原料乳中体细胞数较高与β-酪蛋白和αs-酪蛋白的大量水解有关,并且可能导致UHT乳在贮藏期内出现质量问题。     

Use of reconstituted concentrated nonfat milk for the production of UHT milk: physical and chemical effects and stability

The objective of this work was to evaluate the use of reconstituted concentrated nonfat milk for the production of UHT milk and to evaluate its physical and chemical effects and stability. The study considered three treatments related to the raw material and processing parameters. Increasing the intensity of thermal treatments resulted in increased hydroxymethylfurfural (HMF) content as well as the denaturation of whey protein. During storage, the milk that was produced from reconstituted concentrate displayed a lesser degree of proteolysis and higher pH value, sedimentation index and HMF, compared to natural milk. Under higher storage temperatures, the degree of proteolysis, HMF and pH decreased and the sedimentation index increased.