Chemometric investigation of the volatile content of young South African wines

The content of major volatiles of 334 wines of six different cultivars (Sauvignon Blanc, Chardonnay, Pinotage, Shiraz, Cabernet Sauvignon and Merlot) and vintage 2005 was used to investigate the aroma content of young South African wines. Wines were sourced from six different regions and various producers. Thirty-nine volatile components partially responsible for the flavour of wine were quantified. In order to investigate possible correlation between volatile content and grape variety and/or geographical origin, analysis of variance, factor analysis (FA), principal component analysis (PCA) and linear discriminant analysis (LDA) were used. Significant differences in the levels of certain volatiles were observed as a function of region and cultivar, with the latter factor proving to be more influential. A few volatile compounds were identified as potential predictors of the white wine cultivars. Prediction for red wine cultivars was poor, with the exception of Pinotage wines, for which three compounds (isoamyl acetate, isoamyl alcohol and ethyl octanoate) were identified as accurate predictors. The reasons for the importance of these three volatile compounds in distinguishing young Pinotage wines are discussed, and possible reasons for the unique levels in wines of this cultivar are highlighted.     

冷浸渍过程中真核微生物与小芒森干白葡萄酒香气成分的变化

对不同冷浸渍时间果浆中真核微生物丰度以及葡萄酒中的挥发性成分分别进行测定,以酿酒葡萄小芒森(Petit Manseng)为试验材料,采用1、3、5 d冷浸渍时间处理后酿造干白葡萄酒。采用生物学信息分析、高通量测序方法以及顶空固相微萃取(HS-SPME)与气质联用技术(GC/MS)进行分析。结果表明,冷浸渍过程中shannon指数增加、simpson指数减小,真核微生物丰度呈逐渐增加的变化趋势。另外香气物质总含量呈增加趋势,由348.74增加至402.5 mg/L。酯类化合物呈增加趋势表现最为明显,其中己酸乙酯、2-己烯酸乙酯、5-己烯酸乙酯、辛酸乙酯、癸酸乙酯、棕榈酸乙酯等脂肪酸乙酯类化合物均呈明显上升趋势,脂肪酸乙酯含量呈增长趋势,在冷浸渍1、3、5 d中分别为187.87、199.29、222.07 mg/L。     

蛇龙珠营养系干红葡萄酒中的挥发性风味物质

确定蛇龙珠不同营养系葡萄酒中挥发性风味物质的差异及对其感官品质的影响。利用顶空固相微萃取和气相色谱-质谱联用技术对8 个蛇龙珠营养系干红葡萄酒中50 种主要挥发性成分进行定性和定量检测,采用香气活性值（odor activity value,OAV）、单因素方差分析和主成分分析对测定数据进行处理分析。结果显示：在蛇龙珠干红葡萄酒中β-大马酮等24 种化合物OAV不小于1,对葡萄酒香气具有贡献。乙酸乙酯等12 种化合物可较好实现对8 个蛇龙珠营养系干红葡萄酒的判别分类,E-01、E-02、E-04、E-05营养系间存在明显差异,而E-06、E-07和E-08之间差异很小。结合感官品评结果发现,γ-壬内酯和里哪醇对提高蛇龙珠干红葡萄酒感官品质具有较大贡献,但含量需控制在一定范围内;而壬醛和4-乙基苯酚含量较高会显著降低葡萄酒感官品质,此外,β-大马酮、乙酸乙酯、癸酸乙酯等含量较高也会对葡萄酒的感官品质带来负面影响。蛇龙珠干红葡萄酒的香气特点不是由某个或某类香气成分产生的,是各种香气成分平衡作用的结果。     

Effect of alternative techniques to ageing on lees and use of non-toasted oak chips in alcoholic fermentation on the aromatic composition of red wine

The aim of this work was to evaluate the effect of different enological treatments on the volatile composition of red wine: ageing on lees with and without adding β-glucanase enzymes; the use of a commercial yeast derivative with and without β-glucanase enzymes; and the use of non-toasted chips in fermentation. The results indicated that the presence of chips during the fermentation enhanced the formation of 2-phenylethanol, ethyl esters and fusel alcohol acetates, but affected the levels of some of the lactones and volatile phenols studied negatively. In addition, it was found that wine lees and commercial yeast derivatives can bind some of the volatile compounds studied, mainly ethyl esters and fusel alcohol acetates. After 6 months in bottle, in general, the differences found between the control wine and wines fermented with chips were maintained. However, between the control wine and the wines treated with natural or commercial yeast, the differences disappeared, although not for all the compounds studied. Finally, an important effect of the addition of β-glucanase enzymes was not observed.     

红心火龙果果酒挥发性成分分析

该研究采用顶空固相微萃取(HS-SPME)技术联合气相色谱-质谱(GC-MS)法对火龙果果酒样品中挥发性成分进行分析。结果显示,火龙果果酒中的挥发性成分主要有34种,包括酯类(39.68%)、有机酸类(39.04%)、醇类(16.91%)、醛类(1.09%)、酚类(0.44%)、酮类(0.43%)及其他化合物(2.41%)。相对含量较高的有乙酸(34.63%)、乳酸乙酯(21.83%)、苯乙醇(10.21%)、异戊醇(5.96%)、琥珀酸二乙酯(5.02%)、辛酸乙酯(3.55%)、辛酸(2.44%)、癸酸乙酯(2.21%)、棕榈酸乙酯(2.00%)和十五烷酸乙酯(1.82%)。此外,还检测出少量萜类物质,如D-柠檬烯(1.50%)。结果表明,火龙果果酒中含有大量香气成分,赋予了产品类似酱香型白酒、白兰地、玫瑰及火龙果的特殊香气。     

气相色谱-质谱法分析比较不同酵母发酵红树莓果酒的香气成分

以红树莓为原料,选取1203、1399、SY、RW、F151、F152 6 种果酒酵母进行发酵,通过顶空-固相微萃取法和气相色谱-质谱联用法分别对6 种果酒香气成分萃取、鉴定、分析和比较。结果表明：6 种酵母发酵的酒液中共检测出159 种香气成分,分别为45、56、67、58、66、39 种,其中相同成分占13 种。6 种果酒中的主要香气成分分别为乙醇、癸酸乙酯、辛酸乙酯、癸酸乙酯、癸酸乙酯、癸酸乙酯,含量依次为15.73%、22.05%、15.74%、18.38%、19.14%、15.24%。通过仪器测定和嗅闻感官综合判断,果酒酵母1399发酵的红树莓果酒香气较好,适宜大众口味。     

7 株野生葡萄酒酵母对‘桂葡3号’干白葡萄酒香气成分的影响

对筛选自我国广西毛葡萄产区的汉逊酵母属的Hanseniaspora thailandica（MSF1-4、MG4、MG6、MSF6-2）、伊萨酵母属的Issatchenkia terricola（MG3-1）、酿酒酵母属的Saccharomyas cerevisiae（MSF8-1）和毕赤酵母属的Pichia pastoris（MG1）共7 株酵母酿造‘桂葡3号’干白葡萄酒,分析探讨其理化指标及挥发性香气物质,并以商业酵母K1发酵酒样为对照。结果表明：7?株菌发酵酒各理化指标均符合GB?15037—2006《葡萄酒》要求;共检测到68?种香气物质,实验组香气总量均大于对照组K1;其中辛酸乙酯在乙酯类总含量中高达46.05%,而对照组K1中辛酸乙酯占乙酯总含量的7.12%;MG3-1、MG1、MSF6-2特征香气物质为乙酸苯乙酯、壬醛、4-萜烯醇、芳樟醇、1-辛醇、1-癸醇,MG6的特征香气物质为乙酸异戊酯、香茅醇,MSF8-1、K1、MG4特征香气物质为乙酸乙酯,MSF1-4的香气特征物质为玫瑰醚、月桂酸乙酯、辛酸、癸酸、癸酸乙酯、辛酸乙酯、丁酸乙酯、乙酸己酯、己酸乙酯、辛酸甲酯;其中K1、MG4发酵实验组香气特征最为接近,MG6、MSF1-4发酵实验组香气特征差异最大。上述结果分析得出7?株野生酵母菌具有较强的产辛酸乙酯的能力,MG1、MSF1-4产香能力最好,适合进一步研究开发。     

不同商品酵母对葡萄酒香气成分的影响

以5种不同商品酵母发酵的赤霞珠干红葡萄酒为原料,采用顶空固相微萃取（HS-SPME）和气质（GC-MS）联用技术对其香气成分进行分析,共检测出66种挥发性化合物,定量分析了各葡萄酒中共有的15种主要香气物质之间的差异。结果表明,不同商品酵母发酵葡萄酒中香气种类差别很小,但含量差别明显。酵母BDX具有较强的高级醇生成能力,其中苯乙醇的含量明显高于其他酵母;酵母BM4×4生成的酯类、高级醇和有机酸的含量均处于中间水平;酵母D254具有较强的酯类生成能力,其中辛酸乙酯和己酸乙酯的贡献最为突出;酵母L2323的乙酸异戊酯生成能力较强;酵母RC212的酯类和高级醇生成量最低。     

赤霞珠、蛇龙珠和玫瑰香葡萄酒芳香性成分的差异性研究

芳香类物质种类及含量的差异是决定葡萄酒风味的重要因素。本文对赤霞珠、蛇龙珠和玫瑰香葡萄酒的芳香性成分进行探讨分析。结果表明,3种葡萄酒中3-甲基-1-丁醇的含量最高,相对含量分别为20.61%、21.00%和15.54%;次之为丁二酸单乙酯,含量分别为17.90%、8.94%和16.55%;再次为乳酸乙酯,含量分别为12.36%、17.01%和12.06%。赤霞珠干红葡萄酒中特有的检出成分为乙酸异戊酯和丙酸;玫瑰香葡萄酒中特有的检出成分为3-乙氧基丙醇。蛇龙珠葡萄酒中没有检出1-丁醇、4-酮基-戊酸乙酯和癸酸乙酯,赤霞珠和玫瑰香葡萄酒中均有上述成分;玫瑰香葡萄酒中未检测到(顺)3-己烯-1-醇和糠醇。     

黍米稠酒香气指纹图谱及品质评价体系的构建

目的 构建黍米稠酒香气指纹图谱及品质评价体系, 建立黍米稠酒真伪判别、香气品质标准化的分析方法。方法 采用气相色谱-离子迁移谱法(gas chromatography-ion migration spectrometry, GC-IMS)结合主成分分析(principal component analysis, PCA)从8种市售黍米稠酒样品中筛选构建黍米稠酒风味特征指纹图谱的样本集。利用顶空固相微萃取-气相色谱-质谱法(headspace solid phase microextraction-gas chromatography-mass spectrometry, HS-SPME-GC-MS)检测并基于PCA与偏最小二乘判别分析(partial least squares-discriminant analysis, PLS-DA)构建黍米稠酒风味指纹图谱。结果 黍米稠酒中15种指纹图谱特征物质分别为乙酸乙酯、异戊醇、己酸乙酯、庚酸乙酯、乳酸乙酯、壬醛、辛酸乙酯、乙酸、苯甲醛、癸酸乙酯、月桂酸乙酯、己酸、苯乙醇、棕榈酸乙酯、油酸乙酯。结论 该指纹图谱可准确区分黍米稠酒与非黍米原料稠酒, 并可解析造成黍米稠酒与非黍米原料稠酒香气品质差异的特征挥发性物质。为后期黍米稠酒产地溯源、真伪判别及呈香品质定量效应关系与关键香气物质发酵进程中形成机制解析等提供可靠的指纹物质信息源。     

Volatiles of orange juice and orange wines using spontaneous and inoculated fermentations

The effect of spontaneous fermentation and inoculated fermentation on the volatile compounds of orange wine was studied. The differences on volatile compounds of orange juice and orange wine were also observed. The volatile compounds were analyzed by sensory and instrumental analysis. Solid phase microextraction was used for extraction of volatile compounds. Sensory analysis indicated that no significant differences existed on the wine odor between the two methods. A total of 17 and 19 volatile compounds were identified and quantified in spontaneous and inoculated fermentations, respectively. Esters followed by alcohols and terpenes were the most abundant volatile compounds in the two orange wines. Thirteen of these compounds were present both in the two methods. Totally 31 volatile compounds were found in orange juice, and terpenes were quantitatively the dominant group. Esters were found to be the important volatile compounds formed during fermentation, such as isoamyl acetate, ethyl hexanoate, ethyl benzoate, diethyl succinate, ethyl decanoate and ethyl laurate, etc.     

Volatile components and sensory properties of jujube wine as affected by material preprocessing

Fermented jujube wine, derived from the red jujube berry, has a unique flavor, a mild and sweet taste, and high nutritional value. Among diverse varieties of jujube, Bokjo and the native variety are the most frequently cultivated varieties in Korea. The present study aimed to determine the brewing properties of jujube and to compare the characteristics of fresh and dried fruits of the native and Bokjo varieties for optimal brewing conditions for jujube wine production. We investigated the physicochemical and sensory properties, and we compared the volatile compounds in jujube wine prepared using different methods, through solid-phase microextraction (SPME) GC/MS analysis. The physicochemical properties of jujube wine depended on the drying process rather than the cultivar or the presence of seeds. Sensory properties including aroma and sweetness, which have positive effects on jujube wines, were greater in the whole dried fruit group, while negative properties including grassy aroma, sourness, and bitter taste, were high in the fresh fruit group; these observations contrast their physicochemical properties, as analyzed using dried jujube with seeds. Significant differences were observed in volatile compounds among jujube wine samples. In particular, isoamyl octanoate, isoamyl decanoate, ethyl laurate, ethyl myristate, and 2-phenethyl acetate potentially contribute to the jujube-like flavor of dried jujube wine. These results could be useful as basic data for raw material processing for jujube wine production.     

柑橘果酒酿造过程中挥发性风味化合物的变化

分别以大叶尾张蜜柑澄清果汁及带渣果汁为原料,接种酿酒酵母后以固相微萃取-气相色谱-质谱联用法分别分析酿造7、14、21、28、35 d后果酒中的挥发性风味物质,并采用气相色谱-质谱-嗅觉测量法描述化合物的气味性质并确定气味强度。结果表明：澄清果汁组及带渣果汁组中分别检测出78 种及76 种,主要包括烃类、醇类、醛类、酮类、酯类、酸类;其中酯类是最主要的风味物质,占总量的60%以上,其次是醇类物质,二者在整个过程中均占总量的80%以上。其中,辛酸乙酯、癸酸乙酯及正己酸乙酯是主要的酯类化合物;苯乙醇及1-戊醇是含量最多的高级醇类,在酿造过程中分别呈现降低和升高的趋势,澄清果汁组及带渣果汁组在酿造35 d后含量分别为10.72、59.58 μg/L和8.75、83.17 μg/L。采用气相色谱-嗅觉测量法结合质谱检测技术得出,2 种不同原料对果酒的挥发性风味物质有重要的影响：以柑橘澄清果汁为原料的果酒香气做出主要贡献的特征香味的物质主要有7 种,分别为甲酸异戊酯、正己酸乙酯、D-柠檬烯、苯乙醛、苯乙醇、辛酸乙酯、癸酸乙酯,占总量的68.04%;而对于以带渣果汁为原料的果酒中,分别是丙烯酸2-乙基己酯、正己酸乙酯、苯乙醛、辛酸乙酯、苯乙醇、癸酸乙酯,占总量的48.10%,略有差异。     

Volatile composition of Bobal red wines subjected to alcoholic/malolactic fermentation with oak chips

The effect of wood, in the form of oak chips, on the volatile composition of Bobal red wines caused by adding oak chips at different stages of the fermentation process has been studied. Aroma compounds were isolated by solid phase extraction (SPE) for subsequent analysis by gas chromatography–mass spectrometry (GC/MS). Bobal control wine was produced according to traditional winemaking processes, without oak chips. Oak chips were added to the rest of the wines at two dose levels (3 and 6 g/L) at different stages of the winemaking process: at one week during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Bobal wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids and ethyl, hexyl and isoamyl acetates than the control wine. A similar, trend was observed for higher alcohols. Higher concentrations of benzene compounds, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF followed by young Bobal oak wines. These results reveal that the point of addition during the winemaking process and the dose level of oak chips used have a significant effect on the volatile composition of Bobal red wines.     

Investigation on the role played by fermentation esters in the aroma of young Spanish wines by multivariate analysis

The role played by ethyl esters of fatty acids and by acetates of higher alcohols on the aroma of young wines from neutral grape varieties has been investigated. The statistical methods used have been stepwise linear regression and principal components analysis. Very significant conclusions have been reached. The role played by these compounds depends on the type of wine. In white wines their main role is in the perception of tree fruit and tropical fruit notes. It has been demonstrated that the former notes are linked to ethyl esters, while the latter are linked mainly to acetates of higher alcohols. In rose wines the intensity of tree fruit aroma was correlated with ester content, however no clear conclusion was reached about the role of various compounds on the perception of quality. Finally, in red wines these compounds do not determine the intensity of fruit aromas, and they only play a modulating role on aroma quality. This indicates that red grape varieties must have other aroma compounds which are responsible for the fruity characteristics of wines.     

河西地区不同产地赤霞珠干红葡萄酒挥发性成分分析

以甘肃河西走廊产区5个不同产地葡萄园的赤霞珠葡萄为原料,分别发酵酿造干红葡萄酒,并对样品进行挥发性成分分析,共检测出107种物质,其中主要成分有58种,包括醇类物质19种,酯类物质18种、酸类物质5种、羰基类9种以及其他7种。对比不同产地赤霞珠干红酒发现其挥发性成分在种类和含量均有差异,并表现为各自特有的品质特性。     

Discovering a chemical basis for differentiating wines made by fermentation with 'wild' indigenous and inoculated yeasts: role of yeast volatile compounds

Background and Aims:  Winemakers are constantly searching for new techniques to modulate wine style. Exploiting indigenous yeasts present in grape must is re-emerging as a commercial option in New World wine regions. Wines made with indigenous or 'wild' yeasts are perceived to be more complex by showing a greater diversity of flavours; however, the chemical basis for the flavour characteristics is not yet defined. In order to evaluate techniques for making wine with the 'wild yeast fermentation' character more reliably, it is necessary to define the salient chemical characteristics of such wines.
Methods and Results:  Pairs of Chardonnay wines were prepared from the same must and subjected to similar fermentation conditions in the wineries of origin, except for the mode of inoculation. Reference wines were made by inoculation with a Saccharomyces cerevisiae starter culture, whereas companion wines were allowed to undergo fermentation with the indigenous microflora. Of all wine chemicals analysed, only yeast-derived volatile fermentation products showed significant differences between the yeast treatments.
Conclusions:  Inoculated wines were associated with the esters ethyl hexanoate and 3-methylbutyl acetate and formed a clear cluster by principal component analysis. By comparison with inoculated wines, 'wild' yeast fermented wines showed high variability in volatile compounds that contribute to wine aroma, with higher concentrations of 2-methylpropanol, 2-methylbutanoic acid, ethyl 2-methylpropanoate, ethyl decanoate and ethyl dodecanoate potentially being sensorially important.
Significance of the Study:  This study shows that yeast-derived volatile fermentation products are a key difference between inoculated and uninoculated ferments and provides a chemical basis for the 'wild yeast fermentation' character.