Volatile composition of partially fermented wines elaborated from sun dried Pedro Ximénez grapes

In this work, we used a cell immobilisation system consisting of Penicillium chrysogenum fungi (GRAS) bound to the osmotolerant yeast strains Saccharomyces cerevisiae X4 and X5 for the partial fermentation of raisin musts. The resulting wines were compared with others obtained by partial fermentation of musts with free yeasts and with a traditionally produced sweet wine (i.e. without fermentation of the must). The analysis of volatile compounds grouped by aroma series showed the partially fermented musts had a more complex aroma than the traditional wine. Specially prominent among aroma series was that of ripe fruit, followed by the milky and chemical series. The volatiles with the greatest impact on wine aroma as assessed in terms of odour activity were ethyl hexanoate, ethyl octanoate, butyrolactone, isoamyl alcohols, acetaldehyde, ethyl acetate, 2,3-butanediol, acetoin and 2,3-butanedione. A cluster analysis according to the Ward method was performed to assess the similarity between the traditional sweet wine and those obtained by partial fermentation with free and immobilised yeasts revealed small differences between the wines obtained with free and immobilised yeasts, and marked differences between partially fermented and traditionally obtained sweet wine. The wines provided by immobilised yeasts were the most appreciated in the sensory analysis (especially those obtained with X4 yeasts).     

不同酵母对赤霞珠桃红葡萄酒香气的影响

利用CY3079、Zymaflore X16、TXL和STR四种不同类型的商业酵母发酵赤霞珠新鲜桃红葡萄酒,采用顶空固相微萃取（HS-SPME）结合气相色谱质谱（GC-MS）联用技术,分别对酒精发酵结束和瓶储陈酿一年的葡萄酒样品进行香气物质的定性与定量分析。结果表明,4种酵母发酵的赤霞珠桃红葡萄酒中香气物质的种类相似,但其含量差异显著。酒精发酵结束阶段,CY3079和Zymaflore X16酵母发酵的桃红葡萄酒中脂肪酸乙酯的含量高于其他酵母发酵的酒样,使它们具有更加浓郁的果香、甜香和花香;而Zymaflore X16和STR酵母产生乙酸异戊酯和乙酸苯乙酯的能力较强。经过一年的瓶储陈酿,所有处理的桃红葡萄酒中脂肪酸乙酯和高级醇乙酸酯的含量显著下降,导致其果香的强度降低,同时减少了不同酵母发酵酒样之间的差异。     

Sweet Wine Production by Two Osmotolerant Saccharomyces cerevisiae Strains

The use of Saccharomyces cerevisiae to produce sweet wine is difficult because yeast is affected by a hyperosmotic stress due to the high sugar concentrations in the fermenting must. One possible alternative could be the coimmobilization of the osmotolerant yeast strains S. cerevisiae X4 and X5 on Penicillium chrysogenum strain H3 (GRAS) for the partial fermentation of raisin musts. This immobilized has been, namely, as yeast biocapsules. Traditional sweet wine (that is, without fermentation of the must) and must partially fermented by free yeast cells were also used for comparison. Partially fermented sweet wines showed higher concentration of the volatile compounds than traditionally produced wines. The wines obtained by immobilized yeast cells reached minor concentrations of major alcohols than wines by free cells. The consumption of specific nitrogen compounds was dependent on yeast strain and the cellular immobilization. A principal component analysis shows that the compounds related to the response to osmotic stress (glycerol, acetaldehyde, acetoin, and butanediol) clearly differentiate the wines obtained with free yeasts but not the wines obtained with immobilized yeasts.     

Volatile aroma and sensory analysis of black raspberry wines fermented by different yeast strains

Robus coreanus Miquel is a small berry fruit used for Korean black raspberry (KBR) wine‐making. Twelve different yeast strains were investigated by laboratory‐scale fermentation to develop a wine with a high flavour quality. Volatile aroma compounds from the wines were analysed using headspace–solid phase microextraction–gas chromatography–mass spectrometry and sensory evaluation was performed to evaluate the flavour characteristics. The volatile aroma compounds that mostly contributed to the flavour of KBR wines were those related to fruity (esters) and floral (terpenes) aromas. Fifteen out of the 67 identified volatile compounds showed higher odour activity values than other compounds in the wines, and these compounds were considered as important contributors to the final aromas of the wine. Additionally, the KBR wine fermented by the M1 yeast strain had the highest sensory preference because of higher fruity and floral aroma characters compared with other wines. In addition to the M1 strain, the other yeast strains that produced favourable sensory characteristics included Enoferm CSM, Uvaferm VRB, Lalvin ICV GRE, Lalvin ICV Opale and LevureSeche Active. Of these strains, the M1 strain produced a particularly excellent black raspberry wine, and thus could be applied for further large‐scale production of black raspberry wines. It is also expected that this work will expedite research on the production of high‐quality black raspberry wines with beneficial physicochemical properties, functionality and good sensory characteristics. Copyright © 2015 The Institute of Brewing & Distilling     

Yeast and bacterial modulation of wine aroma and flavour

Wine is a highly complex mixture of compounds which largely define its appearance, aroma, flavour and mouth‐feel properties. The compounds responsible for those attributes have been derived in turn from three major sources, viz. grapes, microbes and, when used, wood (most commonly, oak). The grape‐derived compounds provide varietal distinction in addition to giving wine its basic structure. Thus, the floral monoterpenes largely define Muscat‐related wines and the fruity volatile thiols define Sauvignon‐related wines; the grape acids and tannins, together with alcohol, contribute the palate and mouth‐feel properties. Yeast fermentation of sugars not only produces ethanol and carbon dioxide but a range of minor but sensorially important volatile metabolites which gives wine its vinous character. These volatile metabolites, which comprise esters, higher alcohols, carbonyls, volatile fatty acids and sulfur compounds, are derived from sugar and amino acid metabolism. The malolactic fermentation, when needed, not only provides deacidification, but can enhance the flavour profile. The aroma and flavour profile of wine is the result of an almost infinite number of variations in production, whether in the vineyard or the winery. In addition to the obvious, such as the grapes selected, the winemaker employs a variety of techniques and tools to produce wines with specific flavour profiles. One of these tools is the choice of microorganism to conduct fermentation. During alcoholic fermentation, the wine yeast Saccharomyces cerevisiae brings forth the major changes between grape must and wine: modifying aroma, flavour, mouth‐feel, colour and chemical complexity. The wine bacterium Oenococcus oeni adds its contribution to wines that undergo malolactic fermentation. Thus flavour‐active yeasts and bacterial strains can produce desirable sensory results by helping to extract compounds from the solids in grape must, by modifying grape‐derived molecules and by producing flavour‐active metabolites. This article reviews some of the most important flavour compounds found in wine, and their microbiological origin.     

Differential synthesis of fermentative aroma compounds of two related commercial wine yeast strains

The specific impact of the yeast strain on the wine flavour and aroma has not been well characterised yet because this effect is usually combined with other variables during the winemaking. In this study, the contribution to wine flavour of two Saccharomyces cerevisiae strains widely used in wine production, VIN13 and EC1118, was evaluated after fermentation at 15 °C. Chemical defined grape juice media fermented with the EC1118 strain showed higher solvent, fatty and pineapple aroma attributes, while that fermented with the VIN13 strain exhibited higher banana, fruity, yeasty and green attributes. Sensorial and chemical analyses evidenced that the production of flavour-active compounds is significantly affected by the yeast strain, as well as by the temperature of fermentation, as shown by comparing the former data with those from fermentations carried out at 28 °C under identical culture conditions.     

全果发酵与果渣发酵对欧李果酒香气特征的影响

分别以欧李全果及欧李果渣为原料发酵生产欧李果酒,采用顶空固相微萃取和气相色谱-质谱联用技术检测2 种果酒中芳香成分,并结合不同香气成分的阈值与相对香气活度值,分析2 种欧李果酒香气特征。结果表明：全果发酵欧李果酒检出香气成分50 种,欧李果渣发酵果酒检出香气成分49 种,2 种酒皆含有的香气成分33 种。全果发酵果酒独有香气成分17 种,果渣发酵果酒独有香气成分16 种。2 种欧李果发酵酒的主要香气成分都为辛酸乙酯。在2 种果酒中相对香气活度较大并有突出香气的化合物为辛酸乙酯、β-大马酮、3-甲基丁醛、里哪醇、己酸乙酯、乙酸苯乙酯以及苯乙醇。全果发酵酒具有类似杏仁香气,兼具脂香及果香。果渣发酵果酒具有明显果香,兼具花香、甜香,香气持久稳定。欧李全果发酵与果渣发酵果酒香气成分相对含量及相对香气活度值无显著性差异（P＞0.05）。欧李果渣发酵酒具有典型果酒香型特点,风格明显,同时充分利用欧李果汁生产副产物果渣,更具经济及社会效益。     

The influence of yeast on the aroma of Sauvignon Blanc wine

The main objective of this study was to investigate the effect of different Saccharomyces cerevisiae wine yeast strains on the concentration of aroma-enhancing volatile thiols and fermentation metabolites in Sauvignon Blanc wine. Seven commercial wine yeast strains were selected based on their putative ability to modulate the concentrations of the fruity volatile thiols, 4-mercapto-4-methylpentan-2-one (4MMP), 3-mercapto-hexanol (3MH) and 3-mercapto-hexylacetate (3MHA). Each of these yeasts was used to produce Sauvignon Blanc wines under controlled conditions, in triplicate, in 20-L quantities. The levels of 4MMP, 3MH and 3MHA in these wines were quantified using the p-hydroxymercuribenzoate method. In addition, a total of 24 volatile yeast-derived fermentation aroma compounds were also quantified using headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME–GC–MS). Formal sensory analysis was conducted by 12 trained assessors and, additionally, a panel of 24 experienced wine industry professionals assessed the wines and ranked them in order of preference. The results indicated that the yeast strains varied significantly in terms of their capabilities to (i) produce volatile thiols and fermentation metabolites; and (ii) to modulate the varietal characters of Sauvignon Blanc wine. Yeast strains that produced the highest levels of volatile thiols were responsible for wines with the highest perceived intensity of fruitiness, and these wines were preferred by the tasting panels. While the ‘green’ characters in Sauvignon Blanc wines can be manipulated through vineyard management, the ‘tropical fruity’ characters appear to be largely dependent on the wine yeast strain used during fermentation. Therefore, the choice of yeast strain offers great potential to modulate wine aroma profiles to definable styles and predetermined consumer market specifications.     

戴尔有孢圆酵母对葡萄酒香气的影响

以新疆天山北麓产区和山东乳山产区赤霞珠葡萄为原料,分别选用酿酒酵母、戴尔有孢圆酵母单独发酵以及二者混合发酵,发酵结束后测定葡萄酒的各项理化指标以及挥发性化合物含量。结果表明：2个产地赤霞珠葡萄酒共检测出60种与酵母代谢相关的挥发性化合物,其中醇类23种、酯类26种、酸类8种和酮类3种,不同酵母菌发酵的葡萄酒中的香气成分及含量差异明显;戴尔有孢圆酵母单独发酵产生的醇类、酯类和酸类含量都较高,而与酿酒酵母混合发酵则降低了挥发酸的含量;本实验中戴尔有孢圆酵母明显提高了赤霞珠葡萄酒中乙基酯类的含量,特别是辛酸乙酯、癸酸乙酯和月桂酸乙酯等脂肪酸乙酯,增加了葡萄酒中的果香味;对于原料来自不同产地的葡萄酒,戴尔有孢圆酵母与酿酒酵母混合发酵均可以增强其发酵香气,提高葡萄酒香气的复杂性。     

香气活度值法结合PLSR用于梨酒特征香气物质筛选与鉴定

采用固相微萃取-气相色谱-质谱对市售3种梨酒香气物质进行分离鉴定,共检出43种挥发性成分,其中醇类16种、酯类15种、醛类4种、酮类2种、酚类1种、酸类3种和其他化合物2种。结合香气活度值(odor activity value,OAV)和偏最小二乘回归(partial least squares regression,PLSR)确定梨酒特征香气物质并推断其对梨酒香气的贡献程度。OAV结果表明:梨酒特征香气物质主要为异丁醇、1-辛醇、1-壬醇、苯乙醇、丁酸乙酯、3-甲基丁酸乙酯、乙酸异戊酯、己酸乙酯、辛酸乙酯、β-大马士酮、丁香酚。建立6个感官属性(发酵香、酸香、果香、花香、甜香、清香)与43种香气物质的PLSR模型表明,苯甲醇、正丁醇、丁二酸二乙酯的OAV小于1,但对梨酒的香气有贡献,经OAV确定的梨酒特征香气物质与发酵香和甜香属性具有很好的相关性,而在清香、酸香、果香和花香上的相关性不明显。     

星形假丝酵母在强化赤霞珠葡萄酒玫瑰香气中的应用

采用顶空固相微萃取结合气质联用（HS-SPME-GC-MS）技术测定酿酒酵母（Saccharomyces cerevisiae）CEC01和星形假丝酵母（Candida astrulatum）X11单菌发酵、共同发酵及顺序发酵葡萄酒中的挥发性香气物质,并对结果进行主成分分析（PCA）及聚类分析（CA）,探讨星形假丝酵母X11强化赤霞珠葡萄酒玫瑰香气的条件。结果表明,菌株X11单菌发酵和混合发酵葡萄酒中苯乙醇含量显著高于酿酒酵母CEC01单菌发酵（P＜0.05）,其中,菌株X11和CEC01以1∶10的比例顺序接种发酵的赤霞珠葡萄酒中苯乙醇含量高达12.85 mg/L,赋予葡萄酒浓烈的玫瑰香味。此外,菌株X11在发酵过程中还产生了乳酸丙酯（3.64～7.08 mg/L）、丁酸乙酯（2.55～30.18 μg/L）、辛酸乙酯（476.52～1 997.43 μg/L）等挥发性风味物质,赋予葡萄酒果香和奶酪香。结果表明,星形假丝酵母X11可以显著改善葡萄酒风味,具有一定商业开发价值。     

甜橙果酒酵母筛选及发酵性能

以甜橙果皮和甜橙果园土壤为分离源,共分离到138株酵母菌,经过三级筛选,获得两株适合酿造甜橙果酒的酵母菌S017和F076,经鉴定均为葡萄汁有孢汉逊酵母(Hanseniaspora uvarum),并对其发酵性能进行测试。结果表明：S017、F076的最适发酵温度及pH值分别为24、30℃及5.0、5.5;S017产酒精能力和降糖速率大于F076;与果酒干酵母发酵的酒样相比,两株菌株所发酵的酒样香气浓郁、口感醇厚,具有典型的甜橙果酒风味;S017发酵酒样香气种类多于其余酒样,且特征香气物质己酸乙酯、辛酸乙酯、苯乙醇含量明显高于其余酒样。综合各种性能表明,筛选的菌株S017更适合甜橙果酒的酿造。     

Discrimination of sweet wines partially fermented by two osmo-ethanol-tolerant yeasts by gas chromatographic analysis and electronic nose

Some special sweet wines are obtained by partial fermentation of musts from off-vine dried grapes containing large amounts of sugars. This process is very slow and subject to serious stop problems that can be avoided by using osmo-ethanol-tolerant yeasts. Musts containing 371 g/l of sugars were partially fermented with selected Saccharomyces cerevisiae strains, X4 and X5, to 12% (v/v) and the wines obtained with X5 exhibited a higher volatile acidity but lower concentrations of higher alcohols, carbonyl compounds and polyols than those obtained with X4. A principal component analysis (PCA) of the data provided by an electronic nose (E-nose) afforded discrimination between fermented and unfermented musts, but not between wines obtained with X4 or X5. The PCA applied to the major volatile compounds and polyols shows similar results, but a clear discrimination between wines is obtained by removing the polyols glycerol and 2,3-butanediol from the PCA.     

Indigenous Saccharomyces cerevisiae strains and their influence on the quality of Cataratto, Inzolia and Grillo white wines

The present paper deals with three new strains of Saccharomyces cerevisiae, isolated in old wineries of Sicily, which were microbiologically and molecularly characterized and tested for their ability to produce white wines. Examined in terms of their growth pattern, fermentation vigour, sulphite tolerance, fermentative power, spore formation, and production of acetic acid, hydrogen sulphide and phenolic off-flavours, the strains were utilized as starters in experimental fermentations of musts obtained from the cultivars Inzolia, Grillo and Catarratto. Further, the three musts were also fermented using two commercial S. cerevisiae strains. The quality of the wines produced was confirmed by their principal oenochemical parameters, by sensory analysis and qualitative and quantitative determination of the volatile aroma constituents. All the data were statistically elaborated. Interestingly, the new selected yeasts were able to increase the pear notes (Z)-ethyl-4-decenoate, (E)-ethyl-3-decenoate, and (Z)-ethyl-3-decenoate which are fundamental for the aroma of these Sicilian wines. From our results, the new yeast strains were found to produce white wines of a quality which was not inferior to those obtainable with the best commercial strains selected in other geographical areas, but also with a distinctive aromatic profile.     

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。     

Influence of locally-selected yeast on the chemical and sensorial properties of Albariño white wines

The use of selected yeast strains with improved or novel properties may promote wines with special and original quality attributes. In this paper, changes in the chemical composition (aroma compounds and polyphenols) and sensorial properties of Albariño white wines elaborated with the same must and selected yeast (named as 1, 2 and 3) have been studied in comparison with wines subjected to non-inoculated fermentation (control wine). The results indicated that yeast strain can significantly influence the aroma and polyphenol composition of the wines. Wines elaborated with strain 1 had a higher concentration of terpenes and norisoprenoids, which are compounds closely associated with the fruity and fresh character of Albariño white wines. These same wines had a lower concentration of flavan-3-ols, closely associated with the astringency and bitterness of the wine and the lowest browning potential. The formal sensory analysis conducted by 8 trained judges showed that wines elaborated with strain 1 were preferred by the tasting panel. Therefore, the selection of yeast strains could offer the possibility to modulate sensorial attributes related with the aroma and phenol composition in Albariño white wines.     

产香酵母的分离鉴定及对不同原料酿造甜酒香气成分的影响

该研究从传统颗粒甜酒曲中筛选分离产香酵母菌,结合形态学观察及分子生物学技术鉴定分离菌株,采用顶空-气相色谱（HS-GC）法对筛选菌株产香能力进行分析,并考察产香酵母对不同原料酿造甜酒香气成分的影响。结果表明,共分离筛选出6株酵母,其中5株菌（编号为YRNN1～YRNN5）被鉴定为扣囊复膜酵母（Saccharomycopsis fibuligera）,1株菌（编号为YRJM）被鉴定为酿酒酵母（Saccharomyces cerevisiae）。菌株YRNN5发酵米汁产β-苯乙醇最高（22.98 mg/L）,将其作为甜酒增香菌株应用于不同原料酿造甜酒。甜酒香气成分分析结果表明,籼米甜酒的β-苯乙醇和乙酸苯乙酯含量分别为771.38 mg/L、2.90 mg/L,显著高于籼糯米甜酒（P＜0.05）,且籼米甜酒和籼糯米甜酒的酒精度分别为15.15%vol和12.80%vol。菌株YRNN5和籼米可以作为甜酒发酵的产香酵母和优良原料。