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.     

Effect of nuruk and fermentation method on organic acid and volatile compounds in brown rice vinegar

The effects of different nuruk contents and fermentation methods (AV, vinegar fermented in an agitated culture; SV, vinegar fermented in a static culture) on organic acids and volatile compounds in brown rice vinegars were investigated. In the SV, the contents of acetic, oxalic, tartaric, and malic acids increased with hipher contents of nuruk. Acetic, tartaric, and malic acid contents were higher in the SV than those in the AV. Volatile compounds that can affect vinegar quality, including acetic acid, isoamyl acetate, phenethyl acetate, and phenethyl alcohol were present at high concentrations in the AV. With the increase in nuruk contents in the AV, acetic acid content decreased and isoamyl acetate and phenethyl acetate content increased. No significant differences in sensory scores were observed regarding the amount of nuruk and the type of fermentation. However, electronic-nose analysis showed its potential to effectively differentiate different samples.     

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。     

Evaluation and optimisation of bacterial genomic DNA extraction for no-culture techniques applied to vinegars

Direct genomic DNA extraction from vinegars was set up and suitability for PCR assays performed by PCR/DGGE and sequencing of 16S rRNA gene. The method was tested on 12 intermediary products of special vinegars, fruit vinegars and condiments produced from different raw materials and procedures. DNAs extraction was performed on pellets by chemical, enzymatic, resin mediated methods and their modifications. Suitable yield and DNA purity were obtained by modification of a method based on the use of PVP/CTAB to remove polyphenolic components and esopolysaccharides. By sequencing of bands from DGGE gel, Gluconacetobacter europaeus, Acetobacter malorum/cerevisiae and Acetobacter orleanensis were detected as main species in samples having more than 4% of acetic acid content. From samples having no acetic acid content, sequences retrieved from excised bands revealed high similarity with prokaryotes with no function on vinegar fermentation: Burkholderia spp., Cupriavidus spp., Lactococcus lactis and Leuconostoc mesenteroides. The method was suitable to be applied for no-culture study of vinegars containing polyphenols and esopolysaccharides allowing a more complete assessment of vinegar bacteria.     

Sherry wine vinegar: physicochemical changes during the acetification process

The quality of a wine vinegar is determined by the raw wine substrate and the acetification process employed in its production. Attempts to characterise vinegars have been based on these two features, along with variables such as total extract, glycerol, organic acids, volatile compounds and phenolic composition. When the final products are analysed, it is difficult to evaluate to what extent quality differences are due to the raw material or to differences in production methods, so it is necessary to determine the influence of each feature separately. The present work focuses on monitoring physicochemical changes during the acetification of sherry wine by submerged culture. ANOVA showed significant differences for ethanol, acetic and lactic acids and some volatile compounds (methanol, 1‐propanol, 2‐methyl‐1‐propanol, 2‐methyl‐1‐butanol, 3‐methyl‐1‐butanol, acetoin, acetaldehyde, ethyl acetate and ethyl lactate). However, no statistical changes were found for phenolic compounds during acetification. The phenolic composition of the final product was determined by the substrate employed. In addition, the influence of cycle duration on the chemical composition was studied; the only compound affected by this factor was 2‐methyl‐1‐butanol. © 2001 Society of Chemical Industry     

木瓜复合果醋的酿制

以湖北长阳县的木瓜为基料，配以含糖量较高的苹果汁，制备营养丰富的复合木瓜果醋。结果表明，木瓜汁与苹果汁制成的复合果醋，色泽清亮自然，具有两种果汁的复合香味，口感和香味都优于纯木瓜醋和木瓜菠萝复合果醋。     

Total phenolics, flavonoids and antioxidant activity of tropical fruit pineapple

Pineapple has several beneficial properties including antioxidant activity. The fruit of pineapple was extracted with ethyl acetate, methanol and water. The phenolic content of the extracts was determined by Folin-Ciocalteu method and antioxidant activity was assayed through some in vitro models such as antioxidant capacity by phosphomolybdenum, ??-carotene-linoleate, and radical scavenging activity using ??,??-diphenyl-??-picrylhydrazyl (DPPH) method. The phenolic contents of the extracts as caffeic acid equivalents were found to be highest in methanol (51.1%) followed by ethyl acetate (13.8%) and water extract (2.6%). Antioxidant capacity of the extracts as equivalent to ascorbic acid (??mol/g of the extract) was in the order of methanol extract > ethyl acetate extract > water extract. In comparison with butylated hydroxyanisole (BHA), at 100 ppm of concentration, the antioxidant and free radical scavenging activities of the extracts assayed through ??-carotene-linoleate and DPPH method were also found to be highest with methanol extract followed by ethyl acetate and water extracts. The results indicated that the extent of antioxidant activity of the extract is in accordance with the amount of phenolics present in that extract and the pineapple fruit being rich in phenolics may provide a good source of antioxidant.     

菠萝皮渣糯米果酒发酵过程中主要成分变化研究

以菠萝皮渣和糯米为原料,进行糯米果酒发酵,并采用相关国标检测方法、液相色谱（LC）及气相色谱质谱联用（GC-MS）法,分析菠萝皮渣糯米果酒在发酵过程中可溶性固形物、酒精度、有机酸、挥发酸和香气成分等成分变化。结果表明：发酵过程中糖度迅速降低、酒精度升高后维持稳定,pH值在3.50～3.80之间,呈先降后升趋势,酸度先降低直至陈酿后期轻微升高。有机酸含量在发酵过程中总体呈下降趋势,草酸、酒石酸含量逐渐降低,柠檬酸、苹果酸、丙酮酸、乳酸含量先降后升,琥珀酸和乙酸呈上升趋势。果酒中挥发酸含量不断下降,第60天甲酸、乙酸含量分别为0.30 mg/L和0.26 mg/L。菠萝皮渣糯米果酒中共检测出88种香气成分,其中41种酯类、22种醇类、10种酸类和15种其他类,发酵过程中乳酸乙酯、乙酸异戊酯、2-甲基丁酸乙酯、正己酸乙酯、辛酸乙酯、乙酸苯乙酯、癸酸乙酯、月桂酸乙酯和十六酸乙酯含量较高,相对含量在0.27%～20.57%。     

基于多元统计学分析红曲米醋醋酸发酵阶段挥发性风味特征组分

为探究红曲米醋酿造过程中挥发性风味及特性组分变化规律,以红曲米醋醋酸发酵阶段为研究对象,采用电子鼻、气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）联用和气相色谱-嗅闻（gas chromatography-olfactometry,GC-O）联用技术对挥发性风味物质进行分析,并结合聚类分析、主成分分析和偏最小二乘判别法的多元统计方法进行不同发酵阶段的风味物质差异性分析,最终筛选出特征性组分。电子鼻分析可用于区分不同发酵时期的红曲米醋。通过GC-MS和GC-O识别出发酵过程中共有54 种挥发性风味化合物。经多元统计学方法筛选得到挥发性风味特征组分,醋酸发酵早期为正辛醇、异丁醇和戊酸乙酯;中期为苯甲酸、棕榈酸乙酯、正己醇、2,4-二叔丁基苯酚和乳酸乙酯;中后期为乙酸丙酯、乳酸乙酯和乙酸异丁酯;末期为L(＋)-2,3-丁二醇和庚酸乙酯。本研究结果为红曲米醋香气的调控和风味改善提供重要理论依据。     

Antioxidant capacity of pummelo and navel oranges: Extraction efficiency of solvents in sequence

Extraction efficiency of five different solvents on the antioxidant capacities of pummelo and navel oranges was measured by five widely used antioxidant methods. Freeze-dried edible parts of pummelo and navel oranges were extracted with five different solvents such as hexane, ethyl acetate, acetone, methanol and methanol:water (8:2). The total phenolic content of the extracts was determined by Folin-Ciocalteu method and expressed as catechin equivalents. The highest phenolic content was obtained from ethyl acetate and the minimum phenolic content was found in methanol extract. The dried extracts were screened for their radical scavenging activity using three different methods such as α,α-diphenyl-β-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical assay and ORAC methods. Ethyl acetate extract from navel orange and pummelo was found to be most active radical scavenging activity, whereas hexane extract from pummelo and methanol extract from navel orange was found to be lowest activity. Moreover, all the extracts from pummelo and navel orange were studied for their antioxidant capacity by the formation of phosphomolybdenum complex and reducing power by potassium ferricyanide reduction method at various concentrations. The order of antioxidant capacity of pummelo and navel orange was found to be ethyl acetate>acetone>MeOH:water>methanol> hexane and ethyl acetate>MeOH:water>acetone>methanol>hexane, respectively. Acetone and methanol extracts from pummelo and navel oranges showed highest reducing power than other extracts at 1000 μg/ml. Significant differences in antioxidant capacity were found between the values obtained by the same method in different solvents and as well as each extract antioxidant capacity obtained by the different method. Results of the present study may be due to the extent of antioxidant capacity of each extract is in accordance with the amount of carotenoids, phenolics and vitamin C present in the extracts.     

Antioxidant activity and phenolic content of wine vinegars produced by two different techniques

BACKGROUND: The presence of phenolics in fruit, red wine and vinegar has positive health effects due to their significant antioxidant activity. The aim of the study was to determine the effects of two different vinegar production methods on antioxidant activity and phenolic level of vinegars derived from Ulugbey Karasi grapes. Traditional surface and industrial submerge methods were used to make vinegar. Samples were taken from fresh red grape juice, maceration, wine, traditional vinegar and industrial vinegar. RESULTS: Total phenolic content of traditional and industrial vinegar samples were 2690 mg L^?1 and 2461 mg L^?1 GAE, respectively. ORAC values of traditional and industrial vinegar samples were 10.50 µmol mL^?1and 8.84 µmol mL^?1 TE, respectively. Antioxidant activity values of traditional and industrial vinegars were 13.50 mmol L^?1 and 10.37 mmol L^?1 TEAC, respectively. Gallic acid, catechin, epicatechin, chlorogenic acid, caffeic acid, syringic acid, p‐coumaric acid and ferulic acid were detected in grape juice, wine and vinegar samples. The content of catechin in industrial vinegar (27.50 mg L^?1) was significantly higher than that of in traditional vinegar (13.76 mg L^?1) (P < 0.05). Traditional vinegar had higher amounts of chlorogenic and syringic acids than the industrial vinegar (P > 0.05). CONCLUSION: Results of this study showed that different production methods affected the functional constituents of wine vinegars. Copyright © 2010 Society of Chemical Industry     

不同商业酵母发酵猕猴桃血橙果酒风味物质的主成分分析及聚类分析

采用顶空固相微萃取结合气相色谱质谱联用技术（HS-SPME/GC-MS）检测8种商业酵母发酵的猕猴桃血橙果酒风味物质,结合主成分分析（PCA）和聚类分析（CA）法对果酒的风味物质进行分析和样品分类。结果表明,8个样品中共检测出34种挥发性风味物质,并以酯类、醇类、羧酸等为主。PCA结果表明,猕猴桃血橙果酒中主要风味物质为戊酸乙酯、乙酸苯乙酯、琥珀酸氢乙酯、辛酸乙酯、异丙醇、4-萜烯醇、异植物醇、苯丙醇、乙缩醛、辛酸、（-）-柠檬烯等。CA结果将8个样品聚集为两大类,与主成分分类结果基本一致。     

Inhibitory effect of fermentation byproducts on formation of advanced glycation end-products

Distilled residues (DR) of rice spirit and its derived vinegar produced a negligible inhibitory effect on advanced glycation end-products (AGE) formation. However, recycled DRs of rice spirit and barley spirit and their derived vinegars inhibited formation of N^ε(carboxymethyl)lysine (CML), a major AGE. Unlike the aforementioned DR and derived vinegars, the DR of sweet potato spirit and vinegar, contained very little protein, lysine and arginine, but they most potently inhibited CML formation. The DRs of various spirits and vinegars showed similar free radical-scavenging activities.     

完全发酵与适度发酵苹果醋主要成分的差异性分析

研究苹果醋分别采用适度发酵和完全发酵时主要成分及芳香物质种类和含量的差异性。采用福林-酚法、高效液相色谱法、固相微萃取结合气相色谱-质谱联用分别测定2种发酵方式苹果醋中总酚、有机酸含量和芳香成分。结果表明,适度发酵苹果醋总酚含量比完全发酵高21%;2种果醋的有机酸种类完全一致,但适度发酵法中的酒石酸、柠檬酸和富马酸含量更高,而丙酮酸、苹果酸、α-酮戊二酸、乳酸、乙酸和琥珀酸的含量则略低于完全发酵的醋样。适度发酵苹果醋芳香物质种类更丰富,检测到37种芳香成分,其中保留了不少原果香气,如香茅醇、橙花醇、乙酸丁酯、乙酸-4-甲基-3-己酯和乙酸二甲基丁酯等。适度发酵可减少苹果醋总酚的损失,同时保留了更多的苹果原香物质,是值得探索改善苹果醋品质的途径。     

基于支持向量机的食醋总酸近红外光谱建模

为了得到稳定可靠的食醋总酸光谱模型,以不同产地、不同种类的95个食醋样品为研究对象,应用基于统计学原理的最小二乘支持向量机(LS-SVM)对食醋总酸含量进行光谱分析.对预处理后的光谱进行主成分分析(PCA),以主成分信号作为输入变量建立食醋总酸含量的近红外光谱模型,并与偏最小二乘法(PLS)和向后区间偏最小二乘法(biPLS)模型进行比较.结果表明,LS-SVM模型中的校正集中的相关系数(rc)和交互验证均方根误差(RMSECV)分别达到0.9614和0.2192,预测集相关系数(rp)和预测均方根误差(RMSEP)分别达到和0.919和0.3226,均优于PLS和biPLS模型.研究表明,近红外光谱与食醋总酸含量呈非线性关系,采用LS-SVM建立的模型预测性能更好,精度更高.     

Characterisation of white vinegars of different sources with artificial neural networks

Wine and cider vinegars currently attract growing interest from consumers, giving rise to a consequent increase in supply. A full appreciation of their quality is only possible, however, through recognition of their superior quality when compared with vinegars produced from raw materials of inferior quality. Therefore, it is necessary to pinpoint the parameters that define the quality of these products. Chemico-physical and sensory analysis has been used to draw up artificial neural networks (ANNs), on the basis of a vast sampling of vinegars from various countries, produced from a variety of raw materials, that was already subjected to multivariate statistical analysis. Among the chemical parameters, polyalcohols and other elements such as pH, tartaric acid and proline proved to be highly reliable, whereas other volatile substances and the results of sensory analysis were not very discriminating and could not be used to re-classify samples of unknown origin. The positive results obtained indicate that ANNs are a powerful mathematical tool, since they can be used to construct models that predict the botanical origin of the product and to re-classify samples of unknown origin, without any initial restrictive hypothesis. © 1998 Society of Chemical Industry.     

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。     

New vinegar production from onions

The possibility of producing a new type of vinegar from worthless onions, which fail to meet the quality standards required for marketing, was investigated. Several kinds of onion were initially tested as raw material for vinegar production, and vinegar was successfully produced from the juice of a red onion, the cultivar Kurenai, by batch culture using yeast and Acetobacter aceti. Nutritional analysis revealed that the potassium content of onion vinegar was extremely high, while the amount of sodium was lower than that in conventional vinegars. It was also shown that the total amino acid and total organic acid contents of the onion vinegar were respectively 1.6-6.9 times and 3.5-11.5 times those in other kinds of vinegars.     

VOLATILE CONSTITUENTS OF VINEGAR. I. A SURVEY OF SOME COMMERCIALLY AVAILABLE MALT VINEGARS

Gas liquid chromatography was used to fractionate the alcohols, esters, carbonyls and acids in commercial malt vinegars. A qualitative and quantitative study was made using two different stationary phases; methyl formate, acetaldehyde, ethyl acetate, ethyl alcohol, isobutyl acetate, n-propyl alcohol, n-butyl acetate, isobutyl alcohol, amyl alcohol, acetoin, propionic acid and acetic acid were identified and estimated in eleven different malt vinegars. The results of this survey were compared with the information previously found for malt and other types of vinegars. A preliminary assessment has been made of the origins of these volatiles.