Protection of volatile esters and terpenes during storage of a white wine and a model wine medium by a mixture of N-acetyl-cysteine and caffeic acid

A mixture of N-acetyl-cysteine + caffeic acid, at 10 + 30 mg/L respectively, was tested as inhibitor of the decrease of volatile esters and terpenes during storage of Debina white wine. Moreover, the inhibition of the decrease of isoamyl acetate, ethyl hexanoate and linalool in a model wine medium by the mixture, at 1.25 + 3.75 to 10 + 30 mg/L, was tested. Several volatiles, such as isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate and linalool, decreased during wine storage. The mixture of N-acetyl-cysteine + caffeic acid restricted the decrease of these volatiles to a large extent. In the model medium, the mixture inhibited the decrease of the three volatiles in a dose dependent manner. It was active at any concentration tested. The present results indicate that mixture of N-acetyl-cysteine + caffeic acid, containing each compound at low concentration, may be taken into account as an effective inhibitor of the disappearance of volatile aroma in wines.     

香蕉果酒低温发酵过程中挥发性香气成分的变化

以香蕉果肉为原料,低温条件下酿制香蕉果酒,并采用顶空固相微萃取-气相色谱-质谱联用技术对不同发酵阶段香蕉果酒的易挥发性成分进行分析鉴定,研究香蕉果酒发酵过程中主要香气成分的变化规律。结果表明,在香蕉果酒低温发酵期间(9 d),香气成分总相对含量呈先上升后下降,之后趋于平稳的趋势,其中醇类、酸类和酚类物质含量逐渐增加,分别为31.576%、3.155%、0.705%,而酯类、羰基类和烷烃类占比先增加后减少,总体呈下降趋势,含量分别为35.74%、1.209%、5.388%。同时,香气成分的种类也呈现先增加后减少的趋势,由前期(1 d)的57种降至末期(9 d)的51种。香蕉果酒中主要香气成分为:辛酸乙酯、癸酸乙酯、2-甲基丁基乙酸酯、己酸乙酯、乙酸苯乙酯、乙醇、异戊醇、异丁醇、辛酸、2-戊酮、2-丁烯,这些挥发性成分共同形成了香蕉果酒的独特风味品质。     

Inhibition of the decrease of volatile esters and terpenes during storage of a white wine and a model wine medium by glutathione and N-acetylcysteine

Glutathione and N‐acetylcysteine, each at 20 mg L^?1, were tested as inhibitors of the decrease of volatile esters and terpenes during storage of Debina white wine. Moreover, the inhibition of the decrease of isoamyl acetate, ethyl hexanoate and linalool in a model wine medium by glutathione and N‐acetylcysteine, each at 0–20 mg L^?1, was also tested. Several volatiles, such as isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate and linalool, decreased during wine storage. Glutathione or N‐acetylcysteine significantly restricted the decrease of these volatiles. In the model medium, each thiol inhibited the decrease of the three volatiles in a dose‐dependent manner. N‐acetylcysteine inhibited the decrease of all three volatiles at 2.5 mg L^?1 while glutathione at 2.5 or 5.0 mg L^?1. The present results indicate that glutathione and N‐acetylcysteine may be taken into account as potent inhibitors of the disappearance of aromatic esters and terpenes in wines.     

采用主成分分析法对六个苹果品种果实香气分析及分类

全面分析六个苹果品种果实香气成分特点和主要差异。采用顶空固相微萃取结合气质联用检测香气成分。确定了六个苹果品种特征香气成分,采用主成分分析法确定出乙酸己酯、2-甲基丁酸己酯、乙酸丁酯、乙酸异戊酯、己酸己酯和己醛是苹果香型分类的重要判定变量,将六个苹果品种香气分为三类。各品种均以醛类青香气为主,第一类"醛类浓青香型",酸王香气浓度很高,是其它品种约2～4倍,属于此类;第二类"醛类淡青香型",香气成分比较单纯且含量低,澳洲青苹、国光、瑞丹和瑞林属于此类;第三类"青香蕉香型",酯类香蕉香气化合物含量较高,青香蕉属于此类。     

The evolution of champagne volatiles during ageing

The change in aroma composition during champagne ageing on yeast has been studied by gas chromatography and coupled gas chromatography-mass spectrometry of the volatiles trapped on Porapak Q. Analyses were made on samples kept on yeasts for 2 months and 1, 2, 3, 4, 5, 6, 7 and 16 years, respectively. A rapid increase in the level of volatiles was noted in the first period. As ageing proceeded a slow decrease of nero-lidol, isoamyl butyrate and hexyl acetate level was observed while vitispirane and benzaldehyde concentrations increased. After a 16 year period, benzaldehyde concentration increased to a level of 4 mg litre^?1.     

Influence of the structure of cornstarch dispersions on kinetics of aroma release

ABSTRACT:  This study deals with the impact of food structure and texture on aroma release. This was done with cornstarch dispersions with constant concentrations in starch but differing in their structures. The structure parameters of the cornstarch dispersions were varied by changing the shearing conditions during the pasting process. Linalool and isoamyl acetate were chosen as reference aroma compounds. Linalool is known to form complexes with amylose while isoamyl acetate does not. The release of aroma compounds from starch dispersions under stirring was studied at 2 temperatures by discrete sampling of the headspace. Aroma release curves were modeled and the kinetic and thermodynamic parameters were extracted. The release of linalool seemed to be governed mainly by the interactions (complexation) with starch. In contrast, the interactions between starch and isoamyl acetate were feebler, and the release of this aroma compound was governed by the structure of the starch dispersion. The observed interactions were better established at 20 °C than at 32 °C.     

不同银杏果添加量对花露烧酒风味的影响

目的 通过风味分析确定花露烧酒新品中银杏果的最佳添加量。方法 采用固相微萃取-气质联用(solid phase microexteaction-gas chromatography-mass spectrometry, SPME-GC-MS)和感官评价技术测定比较了不同银杏果添加量的花露烧酒的挥发性风味成分。结果 共鉴定出49种挥发性风味成分,各样品中香气成分的种类和含量有明显差异;经与糯米混合发酵后,银杏果中青草风味成分如壬醛、正己醛等显著下降或未检出;采用主成分分析法得出银杏花露烧酒香气与辛醇、八甲基四硅氧烷、乳酸乙酯、乙酸异戊酯等风味成分有关。由感官分析可知银杏果添加量为25%的样品C整体感官品质最佳,尤其是香气方面,产生了令人愉悦的正己酸乙酯、乙酸异戊酯等风味成分。结论 添加25%银杏果的花露烧酒的风味较好,为传统特色产品花露烧酒的创新提供了新思路,对银杏花露烧酒的风味控制提供了理论依据。     

低浓度乙烯利结合1-甲基环丙烯处理对香蕉果实香气合成的影响

为研究香蕉采后低浓度乙烯利结合1-甲基环丙烯（1-methylcyclopropene,1-MCP）处理对香蕉贮藏过程中香气合成途径的影响,通过气相色谱-质谱（gas chromatography-mass spectrometer,GC-MS）技术、酶活力测定以及实时荧光定量基因表达分析,测定了‘巴西’香蕉（Musa spp. cv. ‘Brazil’）果实不同成熟阶段特征香气物质含量、关键合成酶活力和相关基因表达量。结果表明：单独1-MCP处理和乙烯利（50 μL/L）结合1-MCP（400 nL/L）处理均能明显延缓和抑制香蕉黄熟期特征香气物质（包括乙酸异丁酯、乙酸异戊酯、丁酸丁酯、丁酸异戊酯）和过熟期特征香气物质乙醇和乙酸乙酯、绿硬期特征香气物质己醛和反-2-己烯醛的形成,但乙烯利结合1-MCP处理组与对照组相比各物质含量更接近。单独1-MCP处理和乙烯利结合1-MCP处理都显著抑制了果实香气代谢途径中醇酰基转移酶（alcohol acyltransferase,AAT）、醇脱氢酶（alcohol dehydrogenase,ADH）活力,但乙烯利结合1-MCP处理组AAT和ADH活力与对照组更接近,均显著高于单独1-MCP处理组。两个处理都在贮藏前期提高了酶脂氧合酶（lipoxygenase,LOX）活力,贮藏后期抑制了其活力;抑制ADH1、丙酮酸脱羧酶（pyruvate decarboxylase,PDC）基因的表达,并延缓高峰的出现;延缓支链氨基酸转移酶（branched-chain amino acid transaminase,BCAT）、LOX和AAT基因高峰的出现,但不降低峰值。单独1-MCP处理显著抑制ADH2表达,但乙烯利结合1-MCP处理对ADH2表达影响很小。结论：乙烯利结合1-MCP处理能够有效缓解不适当1-MCP处理引起的香蕉后熟障碍,保持香蕉果实的重要香气品质。本研究结果为1-MCP在香蕉采后品质保持的应用提供了理论依据。     

Production of Isoamyl Acetate from Sugar Beet Molasses by Williopsis saturnus var. saturnus

Three strains of Williopsis saturnus var. saturnus were employed for the production of natural isoamyl acetate (the character impact compound of banana flavour) using sugar beet molasses as the carbon source and batch cultivation at 25°C under anaerobic conditions. Of the three strains, strain HUT 7087 was the best producer of isoamyl acetate, producing 20.7 mg/L. Sugar beet molasses was deemed to be an acceptable carbon source for the production of this flavour compound.     

Effect of short‐term anaerobic conditions on the production of volatiles,activity of alcohol acetyltransferase and other quality traits of ripened bananas

Yellow, ripened (yellow with green tips) bananas were treated with nitrogen gas for 12, 24 and 48 h at 20 °C to study the effects of anaerobic conditions on the fruit quality, including the production of volatile compounds and activity of alcohol acetyltransferase (AAT) during the post‐harvest period. Significantly higher concentrations of acetaldehyde and ethanol were found in the treated fruit than in the untreated bananas after removal from the conditions. The 48‐h treatment showed higher levels of ethanol and acetaldehyde after storage. Immediately after releasing the fruit from the anaerobic atmosphere, the amounts of isobutyl acetate and isoamyl acetate decreased. The production of ethyl acetate increased markedly in each treatment unit 1 day after removing the fruit. Regardless of recovery from the production of isobutyl acetate and isoamyl acetate 1 day after treatment, the banana‐like aroma was denatured because of the production of high levels of ethyl acetate and ethanol. The increase in AAT was slightly lower in nitrogen‐treated fruit than untreated fruit. However, the activity in treated fruit was sufficient for ester production in bananas. The endogenous alcohol levels were increased during nitrogen gas treatment in the fruit due to the inhibition of ester production. Colour development of the bananas was greatly inhibited by the treatments, while the sugar content did not show any differences between the treated and untreated fruit. The results suggest that, even if bananas are removed from the short‐term anaerobic conditions, a loss in quality, except sweetness, easily occurs afterwards, especially the characteristic aroma of the fruit during the post‐harvest period. Copyright © 2006 Society of Chemical Industry     

1‐Methylcyclopropene effects on temporal changes of aroma volatiles and phytochemicals of fresh‐cut cantaloupe

BACKGROUND: Orange‐fleshed cantaloupe melons have intense aroma and flavor but are very perishable during storage life. Fresh‐cut processing enhances ethylene‐mediated quality losses. Post‐cutting 1‐methylcyclopene (1‐MCP) application to fresh‐cut cantaloupe was evaluated for its effects on quality attributes, phytochemical content and aroma volatiles. RESULTS: Fresh‐cut cantaloupe (Cucumis melo var. cantalupensis ‘Fiesta’) cubes treated with 1.0 µL L^?1 of 1‐MCP for 24 h at 5 °C, packaged in vented plastic clamshells and stored under normal atmosphere at 5 °C for 9 days, preserved their soluble solids, total phenolics, total carotenoids and β‐carotene contents, but significant softening occurred. A significant increase of non‐acetate esters and a decrease of aldehydes occurred during storage. Most quality attributes of fresh‐cut cantaloupe were unaffected by the treatment with 1‐MCP. 1‐MCP‐treated fresh‐cut cantaloupe accumulated higher levels of propyl acetate, 2‐methylbutyl acetate, methyl butanoate, methyl 2‐methyl butanoate, methyl hexanoate, 2‐methylbutyl alcohol and phenethyl alcohol, and lower levels of benzyl alcohol and heptanal than untreated controls. CONCLUSION: Post‐cutting treatment with 1‐MCP affected nine of the flavor‐important volatiles, particularly those derived from the amino acids isoleucine and phenylalanine, but had no practical effect on phytochemicals or other quality attributes. © 2012 Society of Chemical Industry     

半干型绍兴黄酒中主要高级醇含量检测及其香气贡献分析

黄酒是我国特有的发酵酒。在种类繁多,风格各异的黄酒中,半干型绍兴黄酒是我国传统黄酒的主要代表之一。其口感柔和、鲜爽,高级醇是其主要风味物质。该研究通过顶空固相微萃取与气质联用的方法检测了半干型绍兴黄酒中关键高级醇的种类及含量,并对其风味贡献进行了分析。结果表明,半干型绍兴黄酒中主要的高级醇主要是异丁醇、异戊醇和β-苯乙醇,其对黄酒风味贡献的顺序为：β-苯乙醇＞异戊醇＞异丁醇,样品加标回收率在97.05%～101.37%,相关系数R＞0.96,相对标准偏差（RSD）为2.16%～5.91%。该结果对科学评价黄酒风味有一定指导意义。     

粉蕉后熟过程中香气品质变化及其关键基因表达特性

为深入了解粉蕉（Musa ABB Pisang Awak）采后品质变化特征,本实验研究了粉蕉（‘广粉一号’）采后常温（25?℃）贮藏过程中果实生理品质、不同成熟阶段果实香气物质变化及香气合成相关基因的表达特性。结果表明：粉蕉果实在采后2?d内硬度急剧下降,果实可溶性固形物质量分数以及可溶性糖含量都显著增加;果实在第6天完熟,第8天已经过熟,此阶段硬度降到很低,同时可溶性糖、总香气物质含量达到最高值,而可溶性固形物质量分数、氨基酸含量在第6天最高。未成熟粉蕉果实的挥发性物质种类及其含量较少,主要以C6～C9的醛类和醇类为主,而酯类极其微量;当果实完熟时挥发性物质含量明显增加,酯类含量明显上升,包括异丁酸异戊酯、乙酸己酯、乙酸异戊酯等,形成粉蕉特有的香气特征。对果实香气合成相关关键基因表达分析发现,脂氧合酶、醇酰基转移酶、醇脱氢酶、支链氨基酸转移酶和氢过氧化物裂解酶基因的表达随着果实成熟软化而增强,果实完熟后又迅速下降;丙酮酸脱羧酶基因的表达量在贮藏前期和后期较高,而在果实成熟的中期表达量很低,与果实在未熟期与过熟期醛类与醇类含量密切相关。本实验初步揭示粉蕉主要挥发性物质在成熟过程中的变化规律及其与相关生理活动的关系,为粉蕉采后的品质保持和保鲜技术提供了理论依据。     

Interactions between flavor compounds and food ingredients and their influence on flavor perception

Interactions between flavor compounds and food ingredients are reviewed and their influence on flavor perception is discussed. Proteins are known to bind flavor compounds. For β-lactoglobulin, the most-studied example, hydrophobic interactions with volatiles are described. The effect of the medium on the conformation of the protein and its ability to bind flavor compounds is discussed. In general, the retention of volatiles by protein is much lower than that by fat. In emulsions, however, the presence of protein at the oil/water interface induces a significant effect on flavor release and flavor perception of hydrophobic flavor compounds. For starch, an extensively studied hydrocolloid, amylose has been shown to form complexes with aroma compounds. The physical state of carbohydrates is one parameter influencing flavor retention. However, the major effect of hydrocolloids seems to be a limitation for the diffusion of aroma compounds due to changes in viscosity. Addition of fat induces significant retention of hydrophobic flavor compounds resulting in noticeable effects on flavor perception. Changing the fat content modifies the overall perception of a mixture of flavor compounds from different chemical classes. The melting point of the fats influences the solubility of aromas and thus the flavor release. Emulsification and droplet size also affect flavor release and perception. More research is required on the effects of real food samples containing mixtures of different flavor compounds.     

搅拌棒萃取-气相色谱-质谱联用法分析‘媚丽’桃红葡萄酒中的香气成分

采用搅拌棒萃取法-气相色谱-质谱联用技术,对‘媚丽’桃红葡萄酒中的香气成分进行定量检测。结果表 明：‘媚丽’桃红葡萄酒中共检测到55 种香气成分,包括26 种酯类物质、4 种酸类物质、9 种醇类物质、6 种萜烯 类物质、3 种C13-降异戊二烯等。通过计算香气活性值发现,其中12 种香气成分对‘媚丽’桃红葡萄酒的香气有重 要贡献。这些物质是：乙酸乙酯、丁酸乙酯、己酸乙酯、辛酸乙酯、乙酸异戊酯、异丁酸乙酯、异戊酸乙酯、异戊 醇、2-苯乙醇、里哪醇、β-大马士酮和β-紫罗兰酮。感官分析结果表明：‘媚丽’桃红葡萄酒具有玫瑰香、苹果、 草莓、菠萝等香气。     

利用废啤酒蒸馏回收酒精及风味物质的研究

采用泡罩式蒸馏塔将废啤酒进行蒸馏,制备废啤酒蒸馏酒。利用气相色谱-质谱联用（GC-MS）仪检测废啤酒和其蒸馏酒中的风味物质,并对废啤酒、废啤酒蒸馏酒以及浓香型白酒的风味进行感官品评。结果表明,共检测出16种主要的醇类、酯类和醛类挥发性物质与废啤酒比较。丁酸乙酯、己酸乙酯、乙酸苯乙酯、正丁醛、2-甲基丁醛、己醛、异戊醛、乙醛这8种风味物质在蒸馏酒中消失;2-苯基乙醇、乙酸异戊酯在蒸馏酒中质量浓度减少;正丙醇、异丁醇、异戊醇、乙酸乙酯、辛酸乙酯、糠醛等风味物质则在蒸馏酒中质量浓度增加。废啤酒蒸馏酒的酯香味突出、香气纯净、风味持久性好。将感官品评结果和主成分分析（PCA）结合发现废啤酒蒸馏酒与浓香型白酒有一定的相似性,可作为白酒基酒使用。     

金银花纯花固态发酵酒风味特征及活性功能成分分析

对金银花纯花固态发酵酿造花酒的风味及其活性功能成分进行研究,应用顶空固相微萃取和气相色谱-质谱联用方法分析金银花酒中重要的香气化合物,结果表明纯花固态发酵金银花酒中主要含有β-大马酮、辛酸乙酯、乙缩醛、3-甲基丁酸乙酯、芳樟醇、苯乙醇、癸酸乙酯、乙酸异戊酯、月桂酸乙酯、己酸乙酯、乙醛、罗勒烯、辛酸异戊酯、2-甲基丁醇、反式丁香烯,其风味与清香型白酒有相似性,同时金银花特征风味明显;金银花固态发酵酒中检测出绿原酸等活性功能成分。利用纯花直接固态发酵工艺酿酒,更有利于原料中的香气、活性功能成分得到大量保留和转移到酒体中,增加酒体风味及活性功能特征。     

不同地区甘薯的酿酒特性及其发酵酒风味物质的分析

分别以安徽、河北、河南、四川、重庆和山东地区的甘薯为原料酿造甘薯酒,并对不同地区甘薯的基本成分、酿造特性和风味物质进行比较。结果表明：不同地区甘薯的基本成分和酿造特性均具有显著性差异,且重庆地区的甘薯酒品质最优;六个地区的甘薯酒中共鉴定出风味物质69种;共有的风味物质为28种,含量较高的风味成分均为乙酸戊酯、己酸乙酯、辛酸乙酯、乙酸苯乙酯、癸酸乙酯、月桂酸乙酯、异戊醇、2-甲基丁醇、β-苯乙醇和辛酸,但不同地区的酒中浓度差异较大;六种甘薯酒中还有一些微量的特有的风味物质,如丁酸异戊酯、α-松油烯及月桂醛等;这些共同的及独特的风味物质构成了不同地区甘薯酒相似和独特的香气与风格。     

‘美乐’和‘威代尔’冰酒在贮藏过程中理化性质和挥发性风味物质的动态变化

对新疆维吾尔自治区伊犁地区生产的‘美乐’和‘威代尔’冰酒在贮藏过程（以0、1 a和2 a代表乙醇发酵结束、贮藏1 a和2 a）中的变化进行监测。为了探讨贮藏期对冰酒质量的影响,采用高效液相色谱法、滴定法、分光光度法和顶空固相微萃取结合气相色谱-质谱联用技术对冰酒的理化性质和香气化合物进行了检测。根据SPSS统计分析结果,依据品种对冰酒的理化指标得到了较好地区分。贮藏2 a后,‘美乐’冰酒中总酸、挥发酸和苹果酸含量分别下降5.9%、13.2%和39%,乳酸含量增加57.2%。贮藏1 a后,褐变指数、酒色、色度、色价、黄色占比和红色占比的含量均有显著变化,色度、色价和黄色占比的含量随贮藏时间的增加呈上升趋势,但红色占比呈下降趋势。贮藏2 a后,‘威代尔’冰酒中的总酸和苹果酸分别增长9.8%和33.1%,而挥发酸下降29.8%。贮藏1 a后‘威代尔’冰酒的酒色、褐变指数、色度、色价和黄色占比的含量显著变化,酒色和色度含量随贮藏时间的延长而增加,但红色占比和蓝色占比与之前相比无差异。根据主成分分析结果,各种冰酒不同贮藏时间后挥发性物质有显著变化,2 种冰酒中的挥发性物质得到明显区分。2 款冰酒产生最多新物质的时期均是贮藏2 a后。其中,‘美乐’冰酒中出现异丙醇、乙酸异戊酯、己酸乙酯、乙酸己酯、癸醛、香茅醇、苯乙酸乙酯、乙酸苯乙酯、β-大马士酮,而在威代尔冰酒中发现：1-戊醇、异戊醇、甲酸乙酯、异丙醇、糠醛、1-丁醇、乙酸异戊酯、3-羟基丁醛、乙酸己酯、乙酸辛酯、3,4-二甲基苯甲醛、5-羟甲基糠醛、乙酸苯乙酯、β-大马士酮。结果表明,贮藏时间对冰酒的理化性质和香气化合物的变化起着关键作用。本实验发现‘威代尔’冰酒的成分在贮存过程中比‘美乐’冰酒的成分更易变。