固相微萃取-气相色谱-质谱法分析中高温大曲发酵、贮存过程中挥发性风味成分的变化

采用顶空固相微萃取-气相色谱-质谱联用(HS-SPME-GC-MS)技术,分析大曲在发酵和贮存过程中香气成分变化规律。结果表明,多数挥发性化合物含量从发酵的第1天开始增加,到第5天达到最大值,随后下降,20 d后趋于稳定;含氮类化合物从发酵的第5天快速增加,第9天达到最大值,发酵20天后含量趋于稳定。     

10种市售鸡肉香精的挥发性风味化合物分析

为了研究市售鸡肉香精的香气组成,本文通过顶空-固相微萃取(HS-SPME)与气相色谱-质谱联用(GC-MS)分析10种商业样品,共检出挥发性化合物131种。其中,萜类、醛类和含硫化合物检出种类最多,分别有25、28和29种,另外,检出化合物还包括酯、呋喃(酮)、酮、吡嗪、酚、醇、酸类等。不同香精其香气组成差异较大,以香气组成最复杂的香精为代表,首次通过气相色谱-嗅闻检测技术(GC-O)剖析鸡肉香精的香气组成,共检出香气活性化合物30种。其中代表性香气活性物质及其主要香型分类如下:主体肉香(甲基(2-甲基-3-呋喃基)二硫醚、甲基糠基二硫醚)、特征脂肪香((E,E)-2,4-庚二烯醛、(E,E)-2,4-壬二烯醛)、葱蒜香(二甲基三硫、二烯丙基二硫醚)、辛香(4-甲氧基苯甲醛、4-乙基愈创木酚)、烘烤香(3-甲硫基丙醛)、甜香(2,4-二氢-2,5-二甲基-3(2H)-呋喃酮、4-羟基-2,5-二甲基-3(2H)-呋喃酮)、酸香(乙酸)和奶香(2,3-丁二酮)。     

清香型大曲中产香细菌的分离筛选及鉴定

为提升麸曲清香型白酒风味品质，该研究采用稀释平板涂布培养法从清香型白酒大曲中分离纯化细菌，采用感官嗅闻法从中筛选出具有产香气功能的细菌菌株，将其应用于麸曲白酒酿造，并通过形态观察及分子生物学技术对其进行菌种鉴定。结果表明，分离筛选得到2株具有香气功能的细菌，编号分别为HXX7和HXX12，其发酵液中挥发性香气成分丰富，均含有酯类、醛酮类、酚类、杂环类化合物等，具有较强产香能力。将菌株HXX7和HXX12分别应用于麸曲清香型白酒生产，其中，菌株HXX7发酵酒样中丁酸乙酯（41.91 mg/L）、4-乙基愈创木酚（148.70 mg/L）、3-羟基-2-丁酮（312.68 mg/L）、苯乙醛（79.27 mg/L）、β-苯乙醇（128.38 mg/L）含量升高。结果表明，菌株HXX7可增加原酒香气，改善原酒风味，从而提升白酒品质。菌株HXX7被鉴定为地衣芽孢杆菌（Bacillus licheniformis）。     

应用GC-O和GC-MS分析酱香型习酒中挥发性香气成分

利用液液萃取法(LLE)提取酱香型习酒中的香气化合物,按照酸碱性将萃取组分分离,获得酸性/水溶性、中性、碱性三个组分,通过气相色谱-闻香法(GC-O)结合气相色谱-质谱(GC-MS)分别进行香气成分分析。在具有典型酱香特征的习酒中共检测出72种香气化合物,其中酸性组分29种,中性组分43种,碱性组分22种,14种香气化合物在两种或两种以上组分中均可检测到。研究发现酱香型习酒中主要的香气物质是酯类、醇类、挥发性有机酸、呋喃类、芳香族类、酚类、醛酮类、吡嗪类以及含硫化合物等。香气强度较大的物质有丁酸乙酯、己酸乙酯、1-丙醇、3-甲基丁醇、乙酸、3-甲基丁酸、糠醛、四甲基吡嗪和二甲基三硫,这些物质对酱香型习酒的风味贡献较大。     

SDE-GC-O-MS鉴定浓香葵花籽油香气活性物质

采用同时蒸馏萃取法（SDE）萃取浓香葵花籽油中的挥发性风味物质,利用气相色谱-质谱-嗅闻技术（GC- O-MS）对香气活性物质进行分离鉴定。SDE的最佳萃取条件为：二氯甲烷40 mL,加油量40 g,水添加量 200 mL,萃取时间3 h。经GC-MS分析共鉴定出96种挥发性风味物质,主要为醛类（29.29%）、杂环类（29.10%）、萜烯类（26.79%）、醇类（3.08%）、烯烃类（1.78%）、酮类（1.47%）、烷烃类（0.57%）、酯类（0.43%）和酸类（0.25%）。GC-O鉴定出24种香气活性物质,主要包括吡嗪类物质,赋予浓香葵花籽油烤香味;萜烯类物质,赋予其包括松针味的植物清香。     

GC-O-MS分析5种酿酒原料中蒸煮香气成分

采用固相微萃取和气相色谱-嗅闻-质谱联用法研究5 种不同酿酒原料的蒸煮香气成分,用谱库进行检索和保留指数验证。结果表明,在高粱、大米、糯米、小麦、玉米分别鉴定出106、96、93、87、80 种香气物质,嗅闻到的化合物分别为26、20、20、15、10 种。其中己酸乙酯、β-苯乙醇、壬醛、反-2-辛烯醛、糠醛、2-戊基呋喃是重要的香气活性物质,对原料香气有显著贡献,贡香比例分别为0.12%～4.73%、0.05%～0.55%、0.06%～1.65%、0.23%～1.64%、0.51%～4.82%和0.06%～1.65%。其中高粱的香气强度比其他原料更为显著。高粱的香气活性物质较多,以酯类、醛类和酮类为主,且萜类物质仅在高粱中嗅闻出。大米和糯米香气活性物质相似,以酯类和醛类物质为主。小麦和玉米香气活性物质少,以醛类物质为主。这些香气活性物质对选择不同的原料酿造白酒具有重要的指导意义。     

Characterization of volatile compounds from Daqu‐a traditional Chinese liquor fermentation starter

Daqu is a fermentation starter and substrate complex that is used to initiate the solid fermentations for the production of Chinese liquor. The aroma of Daqu is one of the most important factors that influence the flavour of Chinese liquor. To further study the aroma of Daqu, volatile compounds in ten Daqu samples were extracted by headspace solid‐phase microextraction (HS‐SPME) and analysed by gas chromatography–mass spectrum (GC‐MS). The samples were pre‐equilibrated at 50 °C for 10 min and extracted with stirring at the same temperature for 30 min prior to injection into a GC‐MS. A total of 75 volatile compounds were characterised by GC‐MS, including twelve alcohols, eleven esters, eight acids, nine aromatic compounds, four phenols, two furans, fourteen nitrogen‐containing compounds and fifteen aldehydes and ketones. By a principal component analysis (PCA), the ten Daqu samples could be classified into three groups according to their origins and, in particular, the production technologies.     

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     

浓香型大曲中酶系与白酒品质的关系研究

大曲在白酒酿造中有产酒和生香的作用,而这些风味物质的形成与大曲中的酶系有很大的关系,从大曲生化性能中水解酶类、酯化酶和其他酶类与酒体中微量成分关系的分析,探讨了大曲酶系与白酒品质的关系。     

GC-MS/GC-O结合化学计量学方法研究不同产地阿胶的关键香气组分

采用同时蒸馏萃取(SDE)和气相色谱-质谱(GC-MS)联合气相色谱-嗅闻(GC-O)技术及化学计量法方法系统地分析了原产地东阿阿胶和其他地区阿胶香气成分的特征与差异,并对东阿阿胶的关键香气组分进行了分离鉴定。经GC-MS共鉴定出65种香气成分,主要为醛类,吡嗪类,其次为酮类,含硫化合物等。经GC-O技术共分离出23种活性香气成分,其中硫代乙酸甲酯、2,6-二甲基吡嗪和2-乙基-3,6-二甲基吡嗪等对阿胶风味贡献较大。化学计量法研究结果表明,不同产地阿胶样品分离明显,5种阿胶间最大相关系数仅为0.5285。GC-MS/GC-O技术联合化学计量学方法不仅能准确鉴定阿胶的关键香气组分,而且为鉴别和评价不同产地阿胶品质提供了一种可靠的技术手段。     

5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine – an aroma-active compound formed in course of the Likens–Nickerson extraction

 5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine (thialdine) is an aroma-active compound that has been isolated from different species of meat. In this study we have investigated the formation of thialdine using the simultaneous distillation–extraction according to Likens–Nickerson for the extraction of aroma compounds. Three isomers of thialdine were identified in the aroma extract of cooked and dried hen meat. It was shown that these compounds are not genuine substances from the sample examined, but that they are artefacts formed during sample preparation. Received: 30 October 1996     

5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine – an aroma-active compound formed in course of the Likens–Nickerson extraction

 5,6-Dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine (thialdine) is an aroma-active compound that has been isolated from different species of meat. In this study we have investigated the formation of thialdine using the simultaneous distillation–extraction according to Likens–Nickerson for the extraction of aroma compounds. Three isomers of thialdine were identified in the aroma extract of cooked and dried hen meat. It was shown that these compounds are not genuine substances from the sample examined, but that they are artefacts formed during sample preparation. Received: 30 October 1996     

Identification of aroma-active compounds in Cheddar cheese imparted by wood smoke

Cheddar cheese is the most popular cheese in the United States, and the demand for specialty categories of cheese, such as smoked cheese, are rising. The objective of this study was to characterize the flavor differences among Cheddar cheeses smoked with hickory, cherry, or apple woods, and to identify important aroma-active compounds contributing to these differences. First, the aroma-active compound profiles of hickory, cherry, and apple wood smokes were analyzed by solid-phase microextraction (SPME) gas chromatography-olfactometry (GCO) and gas chromatography-mass spectrometry (GC-MS). Subsequently, commercial Cheddar cheeses smoked with hickory, cherry, or apple woods, as well as an unsmoked control, were evaluated by a trained sensory panel and by SPME GCO and GC-MS to identify aroma-active compounds. Selected compounds were quantified with external standard curves. Seventy-eight aroma-active compounds were identified in wood smokes. Compounds included phenolics, carbonyls, and furans. The trained panel identified distinct sensory attributes and intensities among the 3 cheeses exposed to different wood smokes (P < 0.05). Hickory smoked cheeses had the highest intensities of flavors associated with characteristic “smokiness” including smoke aroma, overall smoke flavor intensity, and meaty, smoky flavor. Cherry wood smoked cheeses were distinguished by the presence of a fruity flavor. Apple wood smoked cheeses were characterized by the presence of a waxy, green flavor. Ninety-nine aroma-active compounds were identified in smoked cheeses. Phenol, guaiacol, 4-methylguaiacol, and syringol were identified as the most important compounds contributing to characteristic “smokiness.” Benzyl alcohol contributed to the fruity flavor in cherry wood smoked cheeses, and 2-methyl-2-butenal and 2-ethylfuran were responsible for the waxy, green flavor identified in apple wood smoked cheeses. These smoke flavor compounds, in addition to diacetyl and acetoin, were deemed important to the flavor of cheeses in this study. Results from this study identified volatile aroma-active compounds contributing to differences in sensory perception among Cheddar cheeses smoked with different wood sources.     

Characterization of the key aroma compounds in beef extract using aroma extract dilution analysis

Aroma extract dilution analysis (AEDA) of an ether extract prepared from beef extract (BE) and subsequent identification experiments led to the determination of seven aroma-active compounds in the flavor dilution (FD) factor range of 32–128. Omission experiments to select the most aroma-active compounds from the seven aroma compounds suggested that 2,3,5-trimethyl pyrazine, 1-octen-3-ol, 3-methylbutanoic acid, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were the main active compounds contributing to the aroma of BE. Aroma recombination, addition, and omission experiments of the four aroma compounds in taste-reconstituted BE showed that each compound had an individual aroma profile. A comparison of the overall aroma between this recombination mixture and BE showed a high similarity, suggesting that the key aroma compounds had been identified successfully.     

Potent aroma-active compounds of cooked Korean non-aromatic rice

To characterize the aroma of cooked Korean non-aromatic rice, volatiles were extracted by simultaneous steam distillation and solvent extraction (SDE) and dynamic headspace sampling (DHS). The potent aroma-active compounds were then evaluated using gas chromatography-olfactometry. A total of 16 aroma-active compounds with log3 flavor dilution >1 were detected by SDE. On the other hand, 10 aroma-active compounds were detected by DHS. 2-Methyl-3-furanthiol (2-MF) and 2-acetyl-1-pyrroline were considered the most potent aroma-active compounds in cooked Korean non-aromatic rice. Especially, 2-MF was identified for the first time as a potential aroma-active compound of cooked Korean non-aromatic rice.     

Microbial Community Composition Associated with Maotai Liquor Fermentation

The solid‐state fermentation state of Chinese Maotai liquor involves the interaction of several complex microbial communities leading to the generation of the most complex liquor fermentation system in the world and contributes to the unique flavor and aroma of the liquor. In this study, total DNA was extracted from 3 fermented grain samples (FG1, FG2, and FG3) and 12 environmental samples, including Daqu (DA1, DA2, DA3, and DA4), cellar mud (CS1, CS2, and CS3), soil (SL1 and SL2), air (A1 and A2), and sorghum (SH), and the 16S and 18S rRNA genes were amplified. The distribution of typical microorganisms in the samples was analyzed using nested PCR‐denaturing gradient gel electrophoresis, while quantitative PCR amplification of 16S rRNA and internal transcribed spacer genes was performed to estimate the microbial abundance present in each sample. The results indicated that Daqu was the primary source of bacteria, followed by the air, soil, and sorghum samples, while the majority of the fungi responsible for Maotai liquor fermentation were from Daqu and sorghum. Highest bacterial concentrations were found in fermented grains, followed by Daqu and sorghum, while the highest fungal concentrations were found in Daqu, followed by sorghum and an air sample from outside the liquor production area. The findings of this study may provide information regarding the mechanisms responsible for flavor development in Maotai liquor, and may be used to further optimize the traditional art of making liquor.     

清香型志都五谷酒关键香气成分分析

通过液液萃取和顶空固相微萃取技术,结合气相色谱-质谱-嗅闻联用仪分析一种清香型志都五谷酒香气活性成分.通过香气提取稀释分析法共得到40种香气物质,且香气稀释(flavor dilution,FD)因子最大的为异丁酸、月桂酸乙酯、愈创木酚和2-苯乙醇(FD＞4 096),通过质谱、保留指数、香气特征和标准品比对共定性出3...     

酱香型白酒大曲微生物研究进展

酱香型白酒是中国白酒的重要香型,具有“酱香突出,幽雅细腻,酒体醇厚,回味悠长,空杯留香持久”的风格特点,其所具有的独特风味越来越受到消费者的喜欢。大曲在白酒的发酵中有着重要作用,作为白酒的糖化发酵剂,大曲发酵过程中产生丰富的微生物和酶等物质,形成了酱香大曲特有的风味。该文系统综述了酱香型白酒大曲微生物的多样性分析、产香成分分析、酶活研究,以及大曲微生物在酱香型白酒生产中应用的最新研究进展,并对酱香型白酒酿酒微生物的未来的研究提出了思考与展望。     

从微量成分分析浓香型大曲酒的流派

对中国浓香型白酒的两个流派－－川派和江淮派的代表酒五粮液和洋河大曲的微量成分作了分析比较,通过酸、醇、酯、羰基化合物、杂环化合物和挥发性含硫化合物的对比研究后认为,川派与江淮派虽属同一香型,但其在口感和微量成分上存在比较明显的差异,并对差异的产生原因作了简要分析。     

热反应猪肉香精的制备及其气味活性化合物的鉴定

以猪肉蛋白酶解液为基础,与氨基酸、还原糖等物质进行Maillard反应制备猪肉香精,同时通过正交试验和专业评香员的评比,得猪肉香精的最佳配方及条件为：木瓜蛋白酶:肽酶R(Peptidase R)=5:1、加酶量0.3%、底物浓度100%、酶解温度55℃、酶解时间6h、酶解液添加量100.0g、酵母提取物20g、葡萄糖10g、VB1 2g、甘氨酸7g、丙氨酸5g、精氨酸2g、脯氨酸5g、天门冬氨酸5g、半胱氨酸(盐酸盐)9g、呈味核甘酸二钠(IMP 50%+GMP 50%)1.5g、味精4g、木糖1.5g、食盐1.5g、水25g、氧化油脂5g,反应温度125℃,反应时间60min。然后利用两种前处理技术即同时蒸馏提取(simultaneous steam distillation/extraction,SDE)和动态顶空制样(dynamic headspace sampling,DHS)提取猪肉香精的香味成分,采用国内先进的香味分析技术气相色谱-吸闻(gas chromatography-olfactometry,GC-O)技术和质谱(mass spectrometry,MS)技术进行检测分析。同时,采用稀释技术香味提取物稀释分析(aroma extract dilution analysis,AEDA)、动态顶空稀释分析(dynamic headspace dilution analysiis,DHDA)筛选其关键芳香化合物。结果,用同时蒸馏提取物-吸闻-质谱(SDE-GC-O-MS)的方法共检测到30种香味活性化合物,用 动态顶空制样-吸闻-质谱(DHS-GC-O-MS)的方法共检测到40种香味活性化合物,其中两种方法中都被检测到的香味活性化合物有24种。2-戊基呋喃、己醛、1-辛烯-3-醇具有最高的FD因子,这3种化合物在相关猪肉香气的文献报道中也被鉴定出来,是该猪肉香精中对整体香味作出重要贡献的关键芳香活性化合物。