Impact of two Williopsis yeast strains on the volatile composition of mango wine

The aim of the research was to study the volatile composition of mango wine fermented with two Williopsis yeast strains: Williopsis saturnus var. mrakii NCYC500 and W. staurnus var. suaveolens NCYC2586. Thirty terpenoids, twenty‐six esters, ten alcohols, nine acids, seven aldehydes and ketones, two ethers, two phenols and one sulphur compound were identified in the mango wine fermented with strain NCYC500, while twenty‐seven terpenoids, thirty esters, eleven alcohols, eight acids, eight aldehydes and ketones, three ethers, two phenols, one sulphur compound and one furan were detected in the mango wine fermented with the strain NCYC2586. The kinetic changes, final concentrations and odour activity values of major volatiles were compared between the two Williopsis yeast strains and also with other yeast reported in the literature. The results showed that Williopsis yeast strains NCYC500 and NCYC2586 were high producers of acetic acid and acetate esters, but low producers of medium‐ to long‐chain fatty acids and their corresponding ethyl esters. Unlike mango wine fermented with Saccharomyces cerevisiae, most terpenoids derived from mango juice were retained in the resultant mango wine fermented with the two Williopsis yeast strains, suggesting the mango wine could retain the aromatic hints of fresh mango.     

Vinification Effects on Changes in Volatile Compounds of Wine

Alcohols, esters and fatty acids in wines from red, rose and carbonic maceration of Monastrell grapes were measured during yeast fermentation. Isolated volatile compounds were analyzed by gas chromatography alone and with-mass spectrometry. Increases in these compounds was most important during the first days of fermentation and concentrations varied between vinifications. The lower fermentation temperature and shorter skin contact time of rose vinification produced higher concentrations of esters and acids than in red wine. The intracellular fermentation in carbonic maceration vinification resulted in formation of almost all esters and fatty acids before alcoholic fermentation started. The final wine was closer to rose than red wine in aromatic composition.     

Effects of branched‐chain amino acid addition on chemical constituents in lychee wine fermented with Saccharomyces cerevisiae

This study investigated the impact of single branched‐chain amino acid addition (L‐valine, L‐leucine, L‐isoleucine) on nonvolatile and volatile constituents in lychee wine fermented with Saccharomyces cerevisiae MERIT.ferm. The individual addition of branched‐chain amino acids decreased the consumption of proline with significantly different rates. The lychee wine with added L‐leucine and L‐isoleucine had higher odour activity values (OAVs) of isoamyl alcohol, active amyl alcohol and isoamyl acetate. The lychee wine with added L‐valine had higher OAVs of isobutyric acid and isobutyl alcohol (5.55 and 2.98, respectively), which were lower in the wine with added L‐leucine (2.91 and 1.02, respectively) or L‐isoleucine (3.43 and 1.73, respectively) relative to the control wine (4.18 and 1.77, respectively), suggesting interactive effects among the amino acids. These findings demonstrated that lychee wine aroma can potentially be manipulated via the addition of selected branched‐chain amino acids.     

Influence of clarifying agents on the quality of pasteurised palmyra palm sap (Borassus flabellifer Linn.)

The effects of clarifying agents, including bentonite, polyvinylpolypyrrolidone (PVPP), gelatin and chitosan, on the quality attributes of pasteurised palmyra palm sap were evaluated. After clarification and pasteurisation, the lowest polyphenol oxidase (PPO) and invertase activities were detected in the sample clarified with bentonite. PVPP and gelatine were found to be the most effective for removing polyphenol content. In addition, the sample treated with chitosan had the highest transmittance values. However, the sucrose, glucose and fructose contents were not affected by clarification. During storage, the PPO activity, invertase activity, polyphenol content and sucrose level decreased, while the fructose and glucose levels increased with the storage times. According to the Thai Community Product Standard, all pasteurised samples treated with a clarifying agent were acceptable for up to 25 days, whereas the nonclarified sample was spoiled because of the microbial loads. Thus, the clarification process prior to pasteurisation was able to improve the quality and microbiological shelf life of the pasteurised palmyra palm sap for at least 25 days.     

GC/MS法测定五加皮保健酒的挥发性特征成分

建立了用气相色谱-质谱联用法测定五加皮保健酒中桂皮醛、4-甲氧基水杨醛、丁香酚、藁本内酯、对甲氧基桂皮酸乙酯含量的方法,并对10个样品酒进行了检测。采用石油醚-乙醚提取法进行样品前处理,HP INNOWAX毛细管柱分离,离子法(SIM)定量。加标回收率均在91．6％以上。检测结果表明,五加皮保健酒中的挥发性特征成分含量在不同产品之间有较大差异。     

影响荔枝酒甲醇含量的因素

以荔枝肉为原料,采用传统酿酒的方法制备荔枝酒,通过正交试验分析方法优化了影响荔枝酒甲醇含量的主要因素。采用气相色谱法测定其甲醇含量。试验结果表明,影响荔枝酒甲醇含量的因素排序为:温度pH果胶酶量,荔枝酒酿造过程的甲醇含量最少的最佳工艺参数:温度为25℃,pH为5.0,果胶酶0.6g/100mL。     

Volatile Composition of Vernaccia di Oristano Sherry-Like Wine as Affected by Biological Ageing

Forty compounds were identified by gas chromatography and gas chromatography/mass spectrometry in the volatile fraction of Vernaccia di Oristano, an Italian sherry-like wine produced in Sardinia since the 11th century. The individual aromatic compounds were identified and quantified in the original wine, both after biological ageing by inoculation of the original wine with Saccharomyces cerevisiae var bayanus and S cerevisiae var prostoserdovii , and after ageing under sterile conditions. The effects of flor yeasts in terms of production or subtraction of flavour components are discussed.     

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.     

干白葡萄啤酒的研究

利用优质大麦芽、大米、酒花、白葡萄为主要原料 ,经过葡萄的酒精发酵、陈酿 ,再参与啤酒发酵、贮藏过程 ,使产品即保留了传统啤酒的风格 ,又具备干白葡萄酒的特征 ,该产品新颖、独特 ,色、香、味具佳。此产品的开发 ,可充分利用啤酒厂与葡萄酒厂现有设备和我国丰富的葡萄资源 ,节约粮食 ,生产高档啤酒。开拓了啤酒与葡萄酒生产的新途径     

GC-C-IRMS测定葡萄酒中6种风味物质的碳同位素比值

建立一种利用气相色谱-燃烧-稳定同位素比值质谱仪测定葡萄酒中的6种风味物质(乙醇、甘油、异戊醇、乳酸乙酯、乙酸、2,3丁二醇)的碳稳定同位素比值的方法。采用滤膜过滤,稀释或直接上机测定,优化测定方法,风味物质分离完全,分析时间小于20 min。6种风味物质标准溶液测量精度(standard deviation,SD)范围为0.064‰～0.227‰,样品测量精度为0.115‰～0.300‰。利用该技术分析部分葡萄酒样品,结果表明不同地域样品及不同组分间C同位素比值存在一定差异。     

气相色谱法测定黄酒中的高级醇

建立了一种利用毛细管气相色谱法测定黄酒中的高级醇的方法,以峰面积外标法定量测定黄酒中的高级醇,方法的相对标准偏差为1.496%～3.331%,加标回收率为72.20%～115.02%,该方法具有操作简捷、精密度好、准确度高等特点.     

Solid Phase Microextraction for Cheese Volatile Compound Analysis

Cheese headspace volatile compounds were extracted with solid-phase microextraction (SPME) fibers, coated with either polydimethylsiloxane or polyacrylate, and thermally desorbed in the injector port for gas chromatographic (GC) analysis. Results with polyacrylate-coated fibers were better than those with a polydimethylsiloxane fiber. Major cheese volatile components such as volatile fatty acids and 5-lactones were readily extracted by both SPME fibers, but minor components such as volatile sulfur compounds were not observed. SPME-GC patterns were distinctly different among cheese varieties, and characteristic volatile compounds could be identified using multivariate techniques.     

酶标仪比色法检测浊米酒中高级醇含量

为探索酶标仪比色法在浊米酒高级醇含量检测中的适用性,该研究建立了酶标仪比色法检测浊米酒中6种高级醇(异丁醇、异戊醇、苯乙醇、正丙醇、正丁醇、己醇)的单一和混合标准曲线,并对比了酶标仪比色法和气相色谱法对浊米酒中高级醇含量的检测效果.结果表明,酶标仪比色法建立的混合标曲在0～0.05 mg线性均较好,单一标曲中正丙醇在0...     

Volatile flavour components of dalieb (Borassus aethiopum L.)

The volatile components of dalieb fruit have been investigated by capillary column gas chromatography/mass spectrometry. The main components were C1 to C4 aliphatic alcohols and the corresponding acids together with esters derived from them. Acetic acid and ethanol were particularly abundant, the fruit pulp containing approximately 0.1% of each compound. Other volatiles present included the unsaturated ketone 6-methyl-5-heptene-2-one, the corresponding alcohol and the terpene, geranyl acetone.     

发酵保健酒--海藻保健酒

以海藻为原料,提取其有效成分,补充适量的营养物质后,接入生长旺盛的葡萄酒酵母,酿造营养丰富、风味独特的海藻保健酒。     

Odour‐active compounds in pineapple (Ananas comosus [L.] Merril cv. Red Spanish)

Application of solid‐phase microextraction, simultaneous distillation–extraction and liquid–liquid extraction combined with GC‐FID, GC‐MS, aroma extract dilution analysis, and odour activity value was used to analyse volatile compounds from pineapple (Ananas comosus [L.] Merril cv. Red Spanish) and to estimate the most odour‐active compounds. The analyses led to the identification of ninety‐four compounds, seventy‐two of them were positively identified. Twenty odorants were considered as odour‐active compounds, from which ethyl 2‐methylbutanoate, 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone, 1‐(E,Z,Z)‐3,5,8‐undecatetraene, ethyl 3‐(methylthio)propanoate, 1‐(E,Z)‐3,5‐undecatriene, ethyl hexanoate and methyl hexanoate were the most odour contributors and contribute to the typical pineapple aroma, while the others are responsible for fruity and sweet odour notes.