Fermentation of three varieties of mango juices with a mixture of Saccharomyces cerevisiae and Williopsis saturnus var. mrakii

This study was carried out to ascertain the behavior and fermentation performance of mixed yeasts in mango juices of three varieties. Saccharomyces cerevisiae MERIT.ferm and Williopsis saturnus var. mrakii NCYC500 at a ratio of 1:1000 were simultaneously inoculated into juices of three mango (Mangifera indica L.) varieties (R2E2, Harum Manis and Nam Doc Mai). Both yeasts grew well in all juices and there was no early growth arrest of either yeast, but there was late death of W. saturnus var. mrakii NCYC500 in the Nam Doc Mai juice. Fructose, glucose and sucrose were consumed to trace levels in all juices. Changes in citric, tartaric, malic, acetic and succinic acids varied with mango varieties. While the changes of major volatiles were similar in all varieties, there were significant varietal differences in the volatile composition of the resultant mango wines. The volatiles, especially most of the terpenes, of the juices decreased drastically and new volatiles such as β-citronellol were formed. R2E2 wine had more fruity, sweet and creamy notes, and retained more of its original character due to a higher retention of ketones/lactones. Harum Manis wine had the lowest aroma intensity with more green and terpenic notes associated with higher levels of residual terpenes than the other two varieties. Nam Doc Mai wine possessed the highest aroma intensity with winey, yeasty, fruity and floral notes attributed to higher amounts of alcohols, acetate esters and ethyl esters. These findings may help develop different styles of mango wine.     

Effect of fusel oil addition on volatile compounds in papaya wine fermented with Williopsis saturnus var. mrakii NCYC 2251

The impact of fusel oil addition on volatile compounds formation in papaya wine fermented with yeast Williopsis saturnus var. mrakii NCYC2251 was studied with a view to enhancing papaya wine aroma production. Time-course papaya juice fermentations were carried out using W. saturnus var. mrakii NCYC2251 with fusel oil added (0, 0.1 and 0.5% v/v). Fermentation characteristics in terms of yeast growth, Brix and pH changes were similar for all fermentations except for those added with 0.5% (v/v) fusel oil. The addition of 0.5% (v/v) fusel oil inhibited yeast growth. A wide range of volatile compounds were produced during fermentation including acids, alcohols, esters and aldehydes with esters being the most abundant volatile compounds produced. The addition of 0.1% (v/v) fusel oil reduced the production of undesirable volatiles such as ethyl acetate and acetic acid, while increasing the desirable volatiles production such as ethanol and acetate esters. This study suggests that papaya juice fermentation with W. saturnus var mrakii NCYC 2251 together with a low concentration of added fusel oil can be another means of modulating papaya wine aroma compound formation.     

Volatile compounds in chorizo and their changes during ripening

The volatile compounds extracted from both traditional and industrial chorizo—a dry fermented sausage—were analysed by gas chromatography/mass spectrometry (GC/MS). One hundred and twenty-six peaks were detected relating to volatile extracts of which 115 were identified. The substances identified belonged to several classes of chemical: acids, alkanes, alcohols, aldehydes, sulphur compounds, ketones, esters, ethers, phenolic compounds, aromatic hydrocarbons, lactones, nitrogen compounds, terpenes, chloroform and benzofurane. Among the major compounds isolated were acetic acid, allyl-1-thiol and phenol. Larger quantities of most of the chemical groups were found in industrial compared to traditional chorizo, except for sulphur compounds. Typical breakdown products derived from lipid autooxidation were virtually negligible in chorizo. Of the chemicals isolated, sulphur compounds, phenols, acids, ethyl esters and carbonyls could have particular importance to the overall chorizo flavour. In addition, the changes in the proportions of volatile compounds during the ripening of chorizo were tracked. Most of the volatiles increased during ripening, especially acids, alcohols, esters, phenols, ketones and terpenes. On comparing the distribution of the sulphur compounds observed in chorizo with that of garlic, some noteworthy differences were observed. The reason for these differences is based upon several transformations of the sulphur compounds derived from garlic during the ripening and storage of chorizo.     

Analysis of volatile compounds of mango wine

The volatile compounds of mango wine were isolated by continuous solvent extraction and analysed by GC-FID and GC-MS. A total of 102 volatile constituents were identified and quantified. The mango wine accounted for about 9 mg/l of volatile compounds, which included 40 esters, 15 alcohols, 12 terpenes, 8 acids, 6 aldehydes and ketones, 4 lactones, 2 phenols, 2 furans, and 13 miscellaneous compounds. Isopentanol and 2-phenylethanol were the major constituents. A tentative study to estimate the contribution of the identified compounds to the aroma of the wine, on the basis of their odour activity values, indicated that the compounds potentially most important to mango wine included ethyl butanoate and decanal.     

Influence of SO<Subscript>2</Subscript> on the evolution of volatile compounds through alcoholic fermentation of must stabilized by pulsed electric fields

The aim of this work was to study the influence of sulphur dioxide (SO₂) on the formation of volatile compounds by yeast through wine alcoholic fermentation. Thus Parellada must was microbiologically stabilized using a pulsed electric field (PEF) treatment and inoculated with Saccharomyces cerevisiae Na33 strain. Fermentation was carried out with or without SO₂ and the results showed that the evolution of the volatile compounds profile throughout the process was similar. The content of volatile acids in wine obtained by using sulphur dioxide was not significantly different from that fermented without adding the compound. However, the final content of total alcohols and esters was significantly different even thought the differences were small. Consequently, when grape must is treated by PEF the sulphur dioxide concentration usually used in winemaking could be reduced to safer levels or even eliminated without an important effect on the volatile compounds content of the final product. Therefore, the absence of sulphur dioxide should not have a negative impact on the sensory characteristics of wine.     

不同酿酒酵母对甜瓜酒香气品质的影响分析

以酿酒酵母XR、D254、VR、VL1发酵的甜瓜酒为试材,采用顶空固相微萃取和气相色谱-质谱联用技术分别对其进行香气成分分析。结果表明：4 种不同酵母发酵酒样共鉴定出86 种香气成分,包括酯类19 种、醇类29 种、酸类12 种、醛酮类17 种、烯烃类2 种、萜烯类4 种、酚类3 种,其中相同成分有35 种。根据定量结果和气味活度值判断出主要香气贡献物有12 种。通过主成分分析和感官评价综合判断,酵母VL1酿造酒样香气浓郁、协调,品质最佳,是适合甜瓜酒酿造的优良菌株。     

Characterisation of odour‐active compounds in papaya (Carica papaya L.) wine

The volatile compounds of papaya wine were isolated by continuous solvent extraction and analysed by gas chromatography‐flame ionization detector and gas chromatography‐mass spectrometry. A total of 118 volatile constituents were detected, and ninety‐seven were positively identified. The composition of papaya wine included fifty‐three esters, twenty‐two alcohols, nine acids, seven phenols and derivatives, seven sulphur compounds, five lactones, five terpenes, three ketones, two aldehydes and five miscellaneous compounds. The aroma‐active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis and by odour activity values. Six odorants were considered as odour‐active volatiles: ethyl octanoate, (E)‐β‐damascenone, 3‐methylbutyl acetate, benzyl isohtiocyanate; ethyl hexanoate and ethyl butanoate.     

Chemical and volatile composition of lychee wines fermented with four commercial Saccharomyces cerevisiae yeast strains

This study evaluated the chemical and volatile composition of lychee wines fermented with four commercial yeast strains of Saccharomyces cerevisiae: EC‐1118, R2, 71B and MERIT.ferm. Yeast cell population, pH, malic acid, ammonia and some amino acids had significant differences between strain 71B and other strains. There were strain variations with regard to degradation and retention of some juice volatiles as well as formation of new volatile compounds such as most esters and certain terpene compounds. Ethyl octanoate had the highest odour activity value (OAV of 500–1100), followed by ethyl hexanoate (about 50–85), among the common odorants in all lychee wines. Ethyl octanoate reached its highest OAV (1077) in the lychee wine fermented with strain EC1118, whereas ethyl hexanoate had the highest OAV (85) in the wine fermented with strain MERIT.ferm. Cis‐rose oxide, the character‐impact volatile in lychee juice with highest OAV (161), was dramatically reduced to trace levels after fermentation.     

Effects of seven yeast strains on the volatile composition of Palomino wines

The must obtained from Palomino grapes was inoculated with seven different commercial yeast strains (three Saccharomyces cerevisiae cerevisiae– MO5, CEG and IOC BR 8000 and four Saccharomyces cerevisiae bayanus– ALB, KD, REIMS and IOC 2007) and fermented under identical conditions. Standard chemical analyses were done on the final industrial wines and the major volatile compounds extracted and analysed by gas chromatography coupled to mass spectrometry. No differences were found in gross chemical composition, but the wines had significantly different volatile characteristics and the results demonstrated that large sensory differences were generated by the different yeast strain that had been used in the vinification. The major constituents that contributed to the volatile composition in this wine were the higher alcohols, ethyl esters, acetates, fatty acids and volatile phenols. In terms of floral and fruity odours, the best results were obtained for the wines inoculated with IOC 2007, ALB and REIMS S. cer. bayanus strain.     

Evaluation of the potential of commercial non-Saccharomyces yeast strains of Torulaspora delbrueckii and Lachancea thermotolerans in beer fermentation

This work evaluated the potential of three commercial non-Saccharomyces yeast strains Torulaspora delbrueckii (Biodiva and Prelude) and Lachancea thermotolerans (Concerto) for beer fermentation. The fermentation performance, volatile and non-volatile profiles were compared. Growth behaviours of all three yeast strains exhibited similar trends during the initial fermentation phase although a marked population decline was detected in strains Prelude and Concerto, which also showed a rapid utilisation of maltose, while strain Biodiva was unable to consume maltose and consumed lesser amounts of amino acids. Additionally, terpenoids inherently absent in the wort such as β-caryophyllene and geranyl acetone were produced in all beers, significantly higher in beers fermented with strain Prelude. For volatile profiles, Prelude and Concerto produced more ethanol and significantly higher amounts of acetate esters and long-chained ethyl esters. Strain Biodiva, on the other hand, produced higher amounts of isoamyl alcohol and ethyl butanoate.     

两种酿酒酵母发酵对桑葚米酒理化品质及香气成分的影响

实验以清酒酵母和果酒活性干酵母为发酵菌种,分别采用单独接种、两种酵母按不同顺序接种和两种酵母同时接种共5种发酵方式发酵桑葚米酒,利用气相色谱-质谱法(Gas Chromatography-Mass Spectrometry,GC-MS)分析5种发酵方式发酵桑葚米酒中香气物质,同时对米酒中主要香气成分进行主成分分析。结果表明:接种清酒酵母发酵7 d后再接入果酒活性干酵母发酵的桑葚米酒品质较好,米酒理化指标为酒精度(10.10% vol±0.20% vol)、残糖含量(30.70±0.10 g/L)、总酸(6.85±0.08 g/L)、挥发酸(0.31±0.05 g/L)、感官评分(85.60±0.19)。5组酒样中共检测出175种香气成分,其中酯类62种、醇类30种、酸类8种、醛类11种、酮类19种、烃类29种、其它物质16种;接种清酒酵母发酵7 d后再接入果酒活性干酵母发酵的桑葚米酒中主体风味物质达14种,典型风味成分β-苯乙醇的相对含量达17.88%,较其他4种发酵方式高出2.63~3.96倍,米酒的香气浓郁,果香花香和奶香味突出。     

Studies on acetate ester production by non-Saccharomyces wine yeasts

A double coupling bioreactor system was used to fast screen yeast strains for the production of acetate esters. Eleven yeast strains were used belonging to the genera Candida, Hanseniaspora, Metschnikowia, Pichia, Schizosaccharomyces and Zygosacharomyces, mainly isolated from grapes and wine, and two wine Saccharomyces cerevisiae strains. The acetate ester forming activities of yeast strains belonging to the genera Hanseniaspora (Hanseniaspora guilliermondii and H. uvarum) and Pichia (Pichia anomala) showed different substrate specificities and were able to produce ethyl acetate, geranyl acetate, isoamyl acetate and 2-phenylethyl acetate. The influence of aeration culture conditions on the formation of acetate esters by non-Saccharomyces wine yeast and S. cerevisiae was examined by growing the yeasts on synthetic microbiological medium. S. cerevisiae produced low levels of acetate esters when the cells were cultured under highly aeration conditions, while, under the same conditions, H. guilliermondii 11104 and P. anomala 10590 were found to be strong producers of 2-phenylethyl acetate and isoamyl acetate, respectively.     

不同酵母发酵的赤霞珠干红葡萄酒香气成分研究

运用顶空固相微萃取和气相色谱- 质谱- 计算机联机分析,以不同酵母发酵的赤霞珠干红葡萄原酒为原料,采用计算机谱图库检索定性的方法,对三种不同酵母发酵的葡萄酒的主要香气成分进行分析,共检测出65 种化合物。结果表明：赤霞珠葡萄酒中的香气成分主要为酯类、醇类、醛类、烯类和酮类,不同酵母发酵葡萄酒中的香气成分差别微小,而含量差别明显。其中CSM、D254 和F15 酵母发酵的葡萄酒分别检测到56、57、57 种香气成分。三者主要香气含量的差异说明了香气成分的含量与比例在决定葡萄酒香气感官质量上的重要性。     

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。     

香格里拉本土酿酒酵母冰酒发酵产香特征分析

选取云南香格里拉葡萄酒产区4株耐受性好的本土酿酒酵母（Saccharomyces cerevisiae）（编号为CZ10、CZ11、BZL10、BZL12）及目前被广泛用于冰葡萄酒发酵的商业酵母DV10进行赤霞珠冰酒发酵,利用顶空固相微萃取气质联用（HS-SPME-GC-MS）技术检测4株酵母与商业酵母DV10发酵赤霞珠冰酒产品的挥发性香气物质,结合感官评定比较其品质优劣。结果表明,5个试验样品中共检测到67种挥发性化合物,主要包括醇类、脂肪酸乙酯类、乙基酯类、酸类、酮类、萜烯类。其中酵母BZL12生成的香气物质种类最多（62种）,含量最高为490.02 mg/L,其中酯类和醇类总量均分别高于商业酵母DV10 1.61%和4.52%。酵母BZL12发酵葡萄酒的感官评分最高（95分）,理化指标满足相关国标要求,具有生产不同风味特征葡萄酒的应用潜力。     

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。     

紫红曲霉与酿酒酵母共发酵对红曲甜米酒风味的影响

研究紫红曲霉和酿酒酵母在红曲甜米酒发酵过程中风味物质形成的作用。利用紫红曲霉和酿酒酵母以不同比例复配进行甜米酒发酵,监测微生物、有机酸和挥发性香气成分的动态变化。结果表明,以发酵12 h为分界点,酵母菌先增加后减少,而红曲菌则同步呈先减少后增加的趋势;添加红曲菌能够显著促进酵母菌增殖。发酵过程中,酒样的糖度不断降低,酒精度不断增加,发酵36 h后有机酸(乳酸、乙酸、柠檬酸、酒石酸)含量迅速增加;随着红曲菌添加量的提高,糖度减少,酒精和有机酸含量均显著增加。发酵过程共检出47种挥发性组分,包括6种醇类、14种酸类、12种酯类、8种醚类、4种醛酮类、2种醌类和1种酚类,其中高级醇类(苯乙醇、香草醇、异丁醇)和酯类(对羟基扁桃酸乙酯)相对含量较高;酸类含量随发酵时间的延长不断减少,而醇类、酯类和醚类含量则不断增加;添加红曲菌使酯类在发酵前期迅速增加,显著提高其含量。综上所述,添加红曲菌共发酵,促进了酿酒酵母增殖,显著增加了有机酸和酯类等挥发性组分的种类和含量,对甜米酒风味物质的丰富具有重要贡献。     

Modulation of grape wine flavor via the sequential inoculation of Williopsis saturnus and Saccharomyces cerevisiae

The effects of the inoculum ratio of Williopsis saturnus var. saturnus NCYC22 and Saccharomyces cerevisiae var. bayanus EC-1118 at 1:200 and 1:800 on the chemical and volatile compositions of grape wine were studied in sequential fermentation. The grape juice was first inoculated with Williopsis (W.) saturnus for 9 d; thereafter, Saccharomyces (S.) cerevisiae was inoculated to continue the fermentation until d 19. The cell population of W. saturnus disappeared by d 13, with S. cerevisiae dominating until the end of the fermentation in both inoculum ratios. The changes in yeast count, pH, total soluble solids, sugars, organic acids, and amino acids were similar between the two inoculum ratios. A range of volatile compounds was formed, including alcohols, esters, fatty acids, aldehydes, and terpenes. There were significant differences between both inoculum ratios for medium-chain fatty acids (C8, C10, and C12), ethyl esters of fatty acids of C6, C10, C12, and C14 as well as isoamyl octanoate, while other volatiles were statistically the same.     

Comparing the differences of characteristic flavour between natural maturation and starter culture for Mucor‐type Douchi

In this research, effects of maturation times on volatiles of Mucor‐type Douchi were investigated. Results showed that 2‐year matured sample exhibited higher concentrations of characteristic flavours including alcohols, esters, phenols, ketones and pyrazines. Additionally, effects of starter cultures addition on volatiles were investigated, and results demonstrated that inoculated fermented samples presented higher amounts of aldehydes, ketones, phenols and pyrazines compared with that of naturally fermented sample. Analysis of odour activity value (OAV) suggested that increased OAVs of eight compounds that mainly contributed to the flavour of Douchi ranged from onefold to 6.5‐fold in the Tetragenococcus halophilus, Zygosaccharomyces rouxii and Candida versatilis co‐cultured sample. Furtherly, by comparing the characteristic flavour of co‐cultured and 2‐year matured samples, no significant difference was observed in the OAV of flavour except rose‐like and soapy flavour, which indicated that co‐culture of the three strains during Douchi fermentation may facilitate the formation of flavours and shorten the fermentation process.     

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。