Analysis of aroma compounds of commercial cider vinegars with different acidities using SPME/GC-MS, electronic nose, and sensory evaluation

Aroma compounds of commercial cider vinegars according to their acidity (low, moderate, double-strength, and triple-strength) were comparatively investigated. SPME/GC-MS analysis revealed 8 types of aroma compounds commonly existing in the vinegar including acetic acid. A cider vinegar with moderate acidity showed the most volatile profiles. Electronic nose analysis suggested that the peak at 0.40 s was a component related to total acidity of vinegar. Principal component analysis enabled e-nose to discriminate easily by presenting the separated position depending on total acidity. Significant differences with the acidity were observed in the pungent odor intensity and odor preference. According to the results, the moderate acidity vinegar was revealed to retain most volatile profiles and sensory odor. Compared to sensory evaluation, the analysis using SPME/GC-MS and e-nose provided more distinct patterns on their volatile compounds depending on their acidity, which might be a potential tool in determining the volatile profiles of cider vinegars.     

Characterization and differentiation of high quality vinegars by stir bar sorptive extraction coupled to gas chromatography-mass spectrometry (SBSE–GC–MS)

A stir bar sorptive extraction gas chromatography–mass spectrometry (SBSE–GC–MS) method has been used for the characterization of the volatile composition of 26 high quality vinegars of three different protected geographical indications (traditional balsamic vinegar of Modena, balsamic vinegar of Modena, and Sherry vinegar). SBSE technique provided the identification of 113 volatile compounds, which belong to different chemical families (short-chain esters, acids, acetates and alcohols, phenols, lactones and benzenic and furanic compounds). 39 volatile compounds were never previously reported in wine vinegars. This characterization contributed to the differentiation of the 100% of the studied samples on the basis of raw material (two different types of wine, and cooked must), aging type (static and dynamic) and aging time (<5 years, between 5 and 25 years, and >25 years). Furanes and terpenes together with acids and alkanes were the most discriminant variables for raw material and aging time, respectively, whereas for aging type, these ones were acetates and esters.     

食醋陈化期电子鼻的监测研究

利用德国PEN3电子鼻系统快速检测四种食醋陈化期。通过电子鼻采集食醋挥发性成分的响应值,利用主成分分析(PCA)、线性判别分析(LDA)、Fisher线性判别分析(FDA)和多层感知器神经网络(MLPNN)分析进行模式识别,结果表明:LDA分析效果优于PCA分析;并且随着陈化时间的延长,食醋的气味成分变化有增快的趋势,这种气味的变化规律与酸度的变化规律相符。用Fisher线性判别和多层感知器神经网络建立食醋陈化时间的预测模型,发现Fisher线性判别对凤翔醋、陇县醋、金台醋和渭滨醋陈化期的正确检测率分别为100%、100%、98%和100%;多层感知器神经网络对凤翔醋、陇县醋、金台醋和渭滨醋陈化期的正确检测率分别为100%、100%、96.92%和100%。由于正确检测率的高低得出电子鼻结合Fisher线性判别对食醋陈化期的监测结果优于多层感知器神经网络。     

Changes of volatile compounds in wine vinegars during their elaboration in barrels made from different woods

Changes in the volatile components of red wine vinegars and balsamic vinegars were investigated during 1 year of aging in wood barrels and bottles. Barrels of four different woods (oak, chestnut, acacia and cherry) were used. A total of 57 volatile compounds were analysed by Gas Chromatography–Flame Ionization Detection (GC–FID) and Headspace Sorptive Extraction GC–Mass Spectrometry (HSSE-TD–GC–MS). We observed significant increases in the total content of volatile compounds only for balsamic vinegars. The concentrations of ethyl furoate, ethyl benzoate, benzaldehyde and acetophenone were highest in cherry barrels. These compounds, then, seem to be characteristic of this wood. Oak lactones presented the highest increases for vinegars aged in oak. Eugenol was only present in vinegars aged in chestnut and oak barrels. Oak and cherry seem to be the best type of wood for aging of vinegar due to their distinctive aromatic characteristics.     

Discrimination of Chinese vinegars based on headspace solid-phase microextraction-gas chromatography mass spectrometry of volatile compounds and multivariate analysis

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography mass spectrometry (GC-MS) was applied for the determination of the characteristic volatile profiles of Chinese vinegars. Multivariate statistical techniques, such as principal component analysis (PCA) and cluster analysis (CA), were used to characterize the different Chinese vinegars by types, fermentation method, and production area. A total of 56 volatile compounds were identified, including 15 esters, 10 aldehydes, 5 acids, 12 alcohols, 5 ketones, 4 volatile phenols, 2 pyrazines, and 3 miscellaneous compounds. The major compounds in Chinese vinegars were furfural, acetic acid, ethyl acetate, 3-hydroxy-2-butanone, 3-methyl-1-butanol, isopentyl acetate, benzaldehyde, phenylethyl alcohol. The PCA results showed that characterizing the Chinese vinegars by HS-SPME-GC-MS was highly related to their type, fermentation method, and production area, and all these influencing factors were not independent. The CA results indicated that the fermentation method had a greater effect than vinegar type and production area. The results showed that HS-SPME-GC-MS together with chemometrics could provide practical reference for characterization of Chinese vinegars. Practical Application: HS-SPME coupled with GC-MS was applied for the determination of the characteristic volatile profiles of Chinese vinegars. The major compounds in Chinese vinegars were furfural, acetic acid, ethyl acetate, 3-hydroxy-2-butanone, 3-methyl-1-butanol, isopentyl acetate, benzaldehyde, phenylethyl alcohol. HS-SPME-GC-MS together with chemometrics was an efficient tool for evaluating vinegar authenticity.     

Accelerated aging of a Sherry wine vinegar on an industrial scale employing microoxygenation and oak chips

A study of accelerated aging on an industrial scale, employing both microoxygenation and oak chips, of a Sherry wine vinegar has been carried out. The effect of these two factors, microoxygenation and oak chips, on polyphenolic and volatile compounds, and sensorial parameters has been evaluated. The dose of oxygen applied to the vinegar and the use of chips provoke important changes in its content in polyphenols and volatile compounds and make it similar to the profile obtained using traditional aging. An alternative method of aging is proposed, using 5 g/L of chips and a dose of oxygen around 70 mL/L month. With the proposed method, and according to the sensorial and analytical results obtained, vinegars similar to those traditionally aged can be obtained by accelerated aging with microoxygenation and chips in shorter periods of time. In our case, a final reduction of 86% of time is achieved with the proposed method.     

基于电子鼻与气相色谱-质谱联用区分不同陈酿期恒顺香醋风味物质

为区分不同陈酿期恒顺香醋,并构建其香气特征,选取陈酿期3、5、10 a的恒顺香醋作为研究对象,采用电子鼻与气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)方法,并结合主成分分析和载荷分析量化主成分贡献率和样品间风味的区分度。结果显示:电子鼻能够很好地区分3种不同陈酿期香醋的风味,电子鼻传感器W2S、W5S对恒顺香醋香气的区分能力最强。GC-MS分析结果表明糠醛和川芎嗪的相对含量对区别不同陈酿期恒顺香醋贡献率最大。可见,通过电子鼻技术和GC-MS相结合的手段,可以较好区分不同陈酿期的恒顺香醋,可为鉴别不同陈酿期的恒顺香醋提供理论依据和技术参考。     

不同陈酿年份市售山西老陈醋理化指标、风味和功能成分的比较

为了比较市售山西老陈醋（SAV）的品质差异,对不同陈酿年份山西老陈醋样品（陈酿1年（SAV1-1～SAV1-3）、陈酿3年（SAV3-1～SAV3-3）、陈酿5年（SAV5-1～SAV5-3）、陈酿6年（SAV6-1～SAV6-3）、陈酿8年（SAV8-1～SAV8-3）、陈酿10年（SAV10-1～SAV10-3））的理化指标、风味及功能物质进行检测。结果表明,陈酿年份越高,山西老陈醋中的pH、总酸、总酯、还原糖、可溶性固形物、氨基酸态氮、有机酸、大部分氨基酸及总多酚、总黄酮、川芎嗪和乙偶姻等功能物质含量越高,陈酿10年SAV的总酸、总酯、还原糖及氨基酸态氮平均含量最高,分别为8.40 g/100 mL、3.64 g/100 mL、3.91 g/100 mL、0.54 g/100 mL,其中有12种氨基酸的平均含量>0.5 mg/mL,SAV10-2样品中有机酸总量最高,为7.02 g/100 mL。总多酚、总黄酮、川芎嗪均在陈酿8年的醋样中平均含量最高,分别为197.96 mg/100 mL、172.04 mg/100 g、96.89 mg/L。     

HS‐SPME/GC‐MS and chemometrics for volatile composition of Chinese traditional aromatic vinegar in the Zhenjiang region

The main purpose of this study was to determine the volatile composition of Zhenjiang aromatic vinegar, one of the four famous China‐style cereal vinegars, by using headspace solid‐phase microextraction (HS‐SPME)/gas chromatography‐mass spectrum (GC‐MS) and chemometrics. For this purpose, the HS‐SPME sampling method for the volatile compounds of Zhenjiang aromatic vinegar was optimized by a second‐order rotatable central composite experimental design (CCD). A HS extraction of the volatile compounds by incubation on a 65 µm thickness polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre during 44.2 min at 69.5°C with 1.9 g NaCl add gave the most effective and accurate extraction. By the optimized method, a total of 58 volatile compounds, including 9 alcohols, 13 acids, 16 esters, 5 aldehydes, 4 ketones and 8 heterocycle compounds, were identified from 13 aromatic vinegar samples manufactured in Zhenjiang region. By principal components analysis (PCA), the thirteen vinegar samples were classified into 3 groups, and 10 volatile compounds were chosen as characteristic compounds of Zhenjiang aromatic vinegars. Copyright © 2012 The Institute of Brewing & Distilling     

电子鼻分析镇江香醋发酵和陈酿阶段的气味变化

利用PEN3电子鼻对镇江香醋发酵和陈酿过程中挥发性风味进行分析。结果表明,电子鼻能准确稳定地识别醋醅和陈酿醋气味图谱的变化并对不同发酵时间的醋醅和陈酿醋中的败坏醋进行区分;醋醅和食醋的挥发物组成类似,主要是氮氧化合物类、甲烷类、硫化物类、醇类、有机硫化物类;线性判别分析（LDA）和主成分分析（PCA）都能区分各个样品,但PCA对醋醅的区分优于LDA,载荷分析结果表明,醋醅中甲烷类和氮氧化合物类分别对第一、二主成分方差贡献率最大,醋液中甲烷类和硫化物类分别对第一、二主成分贡献率最大。LDA对败坏醋的区分优于PCA。     

四种不同发酵基质柑橘果醋挥发性成分分析

为了研究四种不同发酵基质柑橘果醋挥发性成分的差异,分别以食用酒精发酵柑橘果醋（EACV）、酒醋连续发酵柑橘果醋（WVCV）、酒汁混合发酵柑橘果醋（WJCV）和酒水混合发酵柑橘果醋（WWCV）四种不同发酵基质的柑橘果醋为研究对象,利用电子鼻和顶空-固相微萃取气质联用技术（HS-SPME-GC-MS）,分析不同发酵基质的柑橘果醋挥发性成分的种类和含量。结果表明,四种柑橘果醋中共检测出138种挥发性成分,包括酯类物质34种、醇类物质37种、酸类物质20种、醛类物质8种、酚酮类物质13种、烃类物质10种和其他类物质16种。挥发性成分总含量高低依次为：WVCV＞WWCV＞WJCV＞EACV,其中EACV保留了更多柑橘果汁的气味,其他三种果醋风味更加浓郁。     

山西老陈醋陈酿过程中挥发性香气物质和功能物质的变化规律

对山西老陈醋样品的理化指标、挥发性香气物质及功能物质含量进行测定,并探讨其在不同陈酿时间的变化规律。结果表明,随着陈酿时间在0.5～10年增加,总酸、总酯、氨基酸态氮、氯化钠、还原糖、可溶性固形物、可溶性无盐固形物的含量均呈增长趋势,陈酿10年分别达到11.45 g/100 mL、6.29 g/100 mL、1.17 g/100 mL、1.63 g/100 mL、4.31 g/100 mL、62.00 g/100 mL、53.37 g/100 mL。陈酿样品共检出57种挥发性香气物质,其中酯类含量呈先减少后增加的趋势,酸类含量呈减少趋势,其他类呈增加趋势。陈酿过程中功能物质均呈增长趋势,在陈酿10年最高,总酚、总黄酮、川芎嗪含量分别达到298.62 mg/100 mL、503.62 mg/100 mL、121.79μg/mL。从理化指标、总酚和总黄酮变化来看,陈酿10年最好;从挥发性香气物质、川芎嗪及乙偶姻变化来看,则陈酿5年为宜。     

不同原料发酵原醋中挥发性风味物质成分分析

以八种不同原料发酵的原醋为研究对象，采用固相微萃取-气相色谱-质谱联用（SPME-GC-MS）技术对其挥发性物质成分进行分析。结果表明，八种原醋中共检测出128种挥发性成分，其中大枣、葡萄、山楂、桑葚、柿子、大米、梨、香蕉原醋分别检出60种、51种、47种、47种、38种、37种、35种、29种。八种原醋中共有成分6种，为苯甲醛、乙酸乙酯、乙醇、苯乙醇、醋酸、3-乙酰基-2-丁酮。结合相对气味活度值（ROAV）分析，筛选出31种对八种原醋风味有重要贡献的关键化合物，其中，酯类和酸类物质对八种原醋的风味有着最重要的贡献，是发酵原醋中独特香味来源的主要物质。     

食醋中苯乳酸的提取、鉴定及含量比较

采用高效液相色谱-串联质谱联用（LC-MS/MS）结合核磁共振（NMR）法从山西老陈醋的乙酸乙酯萃取物中分离提取并鉴定出一种新型抗菌物质苯乳酸（PLA）。进一步分析发现,PLA主要在食醋酿造的醋酸发酵阶段产生。对77种来自不同国家食醋中的PLA含量进行分析,结果表明73种食醋中都检测到PLA,且谷物醋中PLA的含量均明显高于果醋中的PLA含量。     

四大名醋的游离氨基酸组成成分分析

目的检测四大名醋中的游离氨基酸,探讨各游离氨基酸对食醋滋味的贡献度,为食醋的质量控制及滋味品质的提高提供基础。方法先用磺基水杨酸溶液对食醋样品进行前处理,再利用30+氨基酸自动分析仪确定游离氨基酸含量。通过计算味道强度值(TAV)确定各游离氨基酸对食醋滋味的贡献率。结果保宁醋氨基酸含量最多为3438.55 mg/100 mL,红曲醋3年陈酿中氨基酸含量最少为737.55 mg/100 mL。保宁醋、镇江香醋、山西老陈醋中对滋味有贡献的氨基酸个数依次为11、8、5。不同酿造年份(3年、5年、8年)的红曲醋中对滋味有贡献的氨基酸个数依次为3、4、4。结论利用氨基酸自动分析仪可确定食醋中游离氨基酸的含量,而味道强度值的引入可计算各游离氨基酸对食醋滋味的贡献率。     

鸭梨、雪梨果醋香气成分的电子鼻分析

利用PEN3电子鼻对雪梨醋和鸭梨醋的香气成分进行了分析。结果表明,二者的特征性香气成分类似,但雪梨醋的芳香味比鸭梨醋略浓。确定了传感器W1W(硫化物)、W2W(有机芳香硫化物)、W5S(氮氧化合物)、W1S(甲烷类)、W2S(醇类)、W1C(芳香成分苯类)和W3S(烷烃类芳香成分)在雪梨醋和鸭梨醋香气评价起主要作用。采用主成分分析法及线性判别法对数据进行分析,发现这两种分析方法均能准确区分出雪梨醋和鸭梨醋。研究结果表明电子鼻香气分析技术可用于梨醋酿造工艺的优化和风味品质监控。      

Multivariate analysis of commercial and laboratory produced Sherry wine vinegars: influence of acetification and aging

One of the problems in the characterization of vinegars is the wide range of values obtained for the main physicochemical and sensorial parameters. The production method, raw material, and wood aging are factors of variation among wine vinegars. Twenty-seven vinegar samples corresponding to different wine substrates (Sherry wine, white wine) and different acetification methods (traditional method, acetification by submerged culture in acetators) were used to perform this study. Selected variables include those that play a major role in the final quality: aroma compounds and organic acids. Principal component analysis (PCA), cluster analysis (CA), linear discriminant analysis (LDA), and classification by artificial neural networks training by back-propagation (BPNN) were used to carry out the characterization. Sherry vinegars made by traditional methods and obtained either in the market or in the wineries were differentiated from Sherry vinegars obtained in the laboratory fermentor (aged or not in wood). Thus, the acetification method plays a major role in the characterization when these variables are considered.     

Multicomposition analysis and pattern recognition of Chinese geographical indication product: vinegar

Multicomposition fingerprints with several chemical compositions containing inorganic elements and organic compounds (amino acids, polyhydric alcohols, organic acids) were measured to distinguish two geographical indication-protected vinegars (GIs) from general vinegars (nGIs). The two of GIs were named Shanxi extra aged vinegar and Zhenjiang vinegar from Shanxi and Jiangsu province, respectively. Principal component analysis and Fisher linear discriminant methods were applied for the pattern recognition and classification of GI product. It was not suitable by simply using one kind of composition to make a distinction between GIs and nGIs. However, by using multicomposition to build a classify model, the classification of SXVs was described by Co, As, Al, Mg, Ca, erythritol, arabitol, sorbitol, proline, lysine and pyruvic acid, while ZJVs classification was described by threonine, serine, glycine, lysine, Ba, erythritol, xylitol and lactic acid. The GI samples can be classified with high accuracy according to the discriminant model, of which the false rate is 3.88 % in SXVs model and 10.85 % in ZJVs model. This method can be a useful method for protecting the geographical indication vinegars from the fake or adulterate vinegar commodities.     

基于无机元素含量的地理标志食醋分类

采用ICP-AES和ICP-MS共测定了山西老陈醋、镇江香醋中38个无机元素的含量。经显著性分析(T检验)筛选出Cd、Al、Ca、Ba、Fe、Mn、Zn、Ni、Pb、Cs、As、Mo等12个在山西老陈醋和镇江香(陈)醋中含量差异最大的特征元素。基于以上12个特征元素,采用主成分分析法对样品进行分类,可明显归于两类,其含量可能与产地的质地条件和产品的生产工艺有关。无机元素含量分析,有望成为一种鉴别地理标志保护食醋的技术手段。     

HS-SPME-GC-MS测定中国四大名醋的香气成分

采用顶空固相微萃取气相色谱质谱联用仪对山西老陈醋、江苏镇江香醋、福建永春老醋、阆中保宁醋不同品牌和年份的8个 醋样进行香气物质检测分析。 结果表明,8个醋样含有酸类10种、酯类14种、醇类4种、酚类6种、醛类10种、酮类4种、吡嗪类5种、呋喃类 4种、其他类11种;四大名醋的香气成分种类繁多且差异明显,其具有各自的独有香气成分,其中山西老陈醋6种,镇江香醋5种,永春 老醋2种,保宁醋4种。 山西老陈醋的吡嗪类成分中2,3,5,6-四甲基吡嗪含量最高,平均580.75 μg/L;镇江香醋B2的乙偶姻中含量最高 为562.6 μg/L。 本研究为进一步研究各类食醋原料、微生物和香气成分之间的关系打下良好基础。