不同氨基酸对普洱熟茶呈味物质和香气成分的影响

氨基酸是普洱茶发酵过程中重要的中间物质,对普洱茶内含物质的转化和品质都有着重要的影响。本文探讨了在发酵时添加不同氨基酸对普洱熟茶产品的主要呈味物质和挥发性香气成分的影响。结果表明,添加外源氨基酸组的水浸出物含量在34.82～39.46%之间,茶褐素含量在6.31～7.17%之间,游离氨基酸的含量在6.31～7.17%之间,这三项指标均高于对照组;茶多酚含量在7.76～8.73%之间,水溶性糖在3.07～3.89%之间,均低于对照组,咖啡碱含量与对照组相差不大。挥发性香气成分分析表明,醇类占香气成分的21.17～25.47%、醛类占15.64～18.71%、杂氧化合物类占13.75～17.92%、酯类占7.17～10.25%,这几类物质是主要的香气成分;实验组香气成分中的酯类和杂氧化合物类含量大于对照组,而它们又是陈年普洱茶的主要的特征香气成分。实验表明外源氨基酸对普洱茶汤中的呈味物质以及香气成分的形成有显著影响,能加快普洱茶特殊品质的形成。     

顶空- 气质联用法测定柚子皮绿茶挥发性成分

采用顶空-气质联用法测定柚子皮绿茶、柚子皮和绿茶原料中的挥发性香气成分,通过对各样品成分的比较,探讨柚子皮绿茶成品香气成分的来源及成因。结果：柚子皮绿茶、柚子皮和绿茶原料的主要成分均为柠檬烯和月桂烯,表明柠檬烯和月桂烯不是由柚子皮转移至绿茶原料的新香气成分;在柚子皮绿茶中检测出几种含氧化合物,占柚子皮绿茶总挥发性成分的5%左右,是区别于绿茶原料和柚子皮的特异性香味物质;并将本方法提取的香气成分与同时蒸馏法进行对比,发现同时蒸馏法提取物含氧化合物比例较高,可能是因为同时蒸馏萃取法高温下长时间反复萃取,样品中的烯烃类物质被氧化所致,而顶空提取法条件较为温和,得到的挥发性成分与样品自然释放的香气成分更为接近。     

模糊数学评价三种配制新疆葡萄蒸馏酒工艺及香气成分分析

基于模糊数学评价法对枸杞甘草配制葡萄蒸馏酒的3种不同加工工艺进行评价,结合顶空固相微萃取-气相色谱-质谱联用技术(headspace solid phase microextraction-gas chromatography-mass spectrometry, HS-SPME-GC-MS)比较3种加工工艺对葡萄蒸馏酒挥发性香气成分的影响,通过主成分分析(principal component analysis,PCA)探究枸杞甘草配制葡萄蒸馏酒中挥发性风味物质种类及相对含量。结果表明:浸提工艺加工的枸杞甘草配制葡萄蒸馏酒总体得分最高,香气种类丰富,特征性风味突出,HS-SPME-GC-MS检测结果与模糊数学评价结果一致,因此确定枸杞甘草配制葡萄蒸馏酒的最佳加工工艺为枸杞甘草浸提法;经检测3种配制葡萄蒸馏酒及基酒有72种挥发性物质,采用主成分分析对3种配制葡萄蒸馏酒的17种共有挥发性物质和5类挥发性化合物进行分析,结果显示:酯类、醇类、酸类和醛类4类化合物是影响枸杞甘草配制葡萄蒸馏酒香气的重要成分,对应的香气化合物为:辛酸乙酯、癸酸乙酯、己酸乙酯、月桂酸乙酯、异戊醇、苯乙醇、辛酸。     

Processing technologies affect the aroma but not the taste of teas: A study of Yunnan Biluochun,Jiangsu Biluochun,and other regular green teas

To evaluate the effect of the processing technology utilized on the quality of teas, the major water-soluble and volatile components of 24 Biluochun and regular green tea samples obtained in different production areas were determined using the sensory evaluation, Folin-Ciocalteu method, the phenol-sulfuric acid method, high-performance liquid chromatography, and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. There were small differences between the contents of the major water-soluble compounds identified in these samples. Sixty-five volatile compounds were identified in these teas. These molecules included 22 hydrocarbons, 18 alcohols, 8 ketones, 6 esters, 3 aldehydes, 3 heterocyclics, 2 nitrogens, 1 lactone, 1 acid, and 1 phenolic. Statistical analyses of these 65 compounds using principal component analysis and cluster analysis revealed that the contents of the Biluochun samples were highly similar and were different from those of the regular green teas. This study suggested that, although the geographical origin and cultivar influenced the aroma characteristics of tea products somewhat, processing technologies played an important role on tea aroma.     

不同年份不同质量等级李渡白酒香气成分分析

目的 分析比较不同年份不同质量等级李渡白酒的香气成分差异。方法 通过感官评价、直接进样、顶空萃取和顶空固相微萃取结合气相色谱-质谱联用仪、气相色谱-离子迁移谱以及气相色谱-嗅闻-质谱联用仪分析了17个李渡酒中的香气成分,通过计算香气活性值(OAV)确定重要香气活性化合物,结合偏最小二乘法分析得到差异香气物质。结果 共鉴定出李渡酒中的92种挥发性化合物,26种香气活性化合物;浓度最高的化合物是乳酸乙酯(2538.18 mg/L);己酸乙酯(OAV: 876~220920)等8种化合物香气贡献较大,酯类化合物的贡献最大,一级、二级、优级的李渡酒三年、五年的重要香气化合物香气强度更强,含量更高;且己酸乙酯等6种化合物、苯乙醇等18种化合物分别是导致不同年份、不同质量等级酒样产生差异的重要物质。结论 本研究分析鉴定了17个李渡酒样的香气物质,找到了导致不同年份不同质量等级酒样之间香气差异的化合物,为李渡酒的风味调控提供了参考数据。     

脐橙全果酒发酵工艺优化及其与脐橙果汁酒风味物质的对比分析

以脐橙全果为原料酿造脐橙全果酒,采用单因素试验和Box-Behnken试验设计,分析酵母接种量、发酵温度、发酵时间对脐橙全果酒发酵的影响。结果表明其最佳条件为：酵母接种量6.4%、发酵温度28 ℃、发酵14d。同时,采用顶空固相微萃取法、利用气相色谱-质谱联用技术对脐橙全果酒和脐橙果汁酒风味物质进行分析。结果表明：在脐橙全果酒和脐橙果汁酒中分别检出25 种和11 种挥发性香气物质,且脐橙全果酒的香气活性成分主要为萜烯类,占香气成分的66.00%,而脐橙果汁酒的主要香气成分为醇类,所占比例为91.95%。     

基于GC×GC-TOF-MS法比较两种不同香型白酒的挥发性香气成分

为比较大曲清香型白酒和复合香型白酒中的挥发性香气成分,以明确不同香型白酒的香气特点,采用顶空固相微萃取（HS- SPME）结合全二维气相色谱-飞行时间质谱法（GC×GC-TOF-MS）分别检测2种香型白酒中的挥发性香气成分,并对各挥发性香气成分进行分类对比。结果表明,采用多级鉴定策略,分别在大曲清香型白酒和复合香型白酒中确认了可信度较高的挥发性香气成分251种和341种,主要包括酯类、醇类、酸类、醛酮类,还包括呋喃类、含氮、含硫及其他类物质。在复合香型白酒中鉴定出的特有挥发性含硫和吡嗪类化合物分别为8种和7种,二者为区别于大曲清香型白酒的特征香气成分。白酒香气成分及其感官特征关联分析结果表明,复合香型白酒具有“香气复合幽雅”的风格特点。     

液液萃取与顶空固相微萃取结合气相色谱-质谱法分析金种子馥合香白酒香气成分的比较

为明确不同前处理方法对白酒挥发性香气成分的提取效果,分别采用液液萃取法（Liquid-liquid extraction, LLE）和顶空固相微萃取法（headspacesolid phase microextraction, HS-SPME）作为酒样的前处理方法提取金种子馥合香白酒中的挥发性香气成分,再结合气相色谱-质谱法（GC-MS）进行定性与相对定量分析。结果表明：两种不同方法检出的共有组分有28种,特有组分分别有35种和18种。LLE对酯类、醇类、酸类以及其他物质具有很好的萃取效果,但是对于易挥发性物质萃取效果较差;HS-SPME对痕量、易挥发性的物质具有较好的萃取效果,但对难挥发性物质的萃取效果较差。LLE能富集到较多种类的香气物质,HS-SPME能富集到更高含量的香气成分。酒样的两种不同前处理方法各有特点,相互补充并结合分析可为白酒挥发性香气成分的检测提供更加全面完整的数据支持。     

Release of aroma compounds from dry-fermented sausages as affected by antioxidant and saliva addition

The effect of the addition of an antioxidant and saliva on the release of aroma compounds from dry fermented sausages was studied by extracting the headspace at different times using solid phase micro-extraction technique. The compounds were analysed by gas chromatography using a FID detector and identified by mass spectrometry. The addition of butylated hydroxytoluene to dry fermented sausages produced a significant reduction of the release of most of the volatile compounds indicating an oxidation process during sampling. The addition of water and saliva to the dry fermented sausages produced a higher release of pentanal, hexanal and octanal, whilst pentane, 1-octanol, pentanoic acid, and propanal showed a lower rate of release. Moreover, phenylethyl alcohol, 2-butanone, 2,3-pentanedione and 2-nonanone, derived from bacterial metabolism, presented a lower release rate when water and saliva were added. The rate of release of the compounds from dry fermented sausages was not related with the compound hydrophobicity value. Further research is needed to elucidate the effect of fermented sausage matrix on the partitioning of the compounds and its effect on aroma perception.     

Headspace concentration of selected dry-cured aroma compounds in model systems as affected by curing agents

The effect of curing agents (sodium chloride, nitrate, nitrite, glucose, and ascorbic acid) on the headspace concentration of six volatile compounds (2-methyl-butanal, 3-methyl-butanal, 2-pentanone, hexanal, methional, and octanal) has been studied. These volatile compounds were selected based on their presence and contribution to the flavour of typical Spanish dry-cured meat products. The release of volatile compounds to the headspace has been studied by using solid-phase microextraction (SPME) and gas chromatography analysis. The main effect was produced by sodium chloride, because it produced a salting-out effect on all the volatile compounds studied. Furthermore, the presence of nitrite, nitrate, and ascorbic acid in the solution also produced an increase in the headspace concentration of the volatile compounds while glucose decreased the headspace concentration of octanal and hexanal. The changes in the relative proportions of volatile compounds due to the effect of curing agents should be taken into account as they may change the flavour perception of dry-cured meat products.     

新型顶空固相萃取罐研制及其在鱼香肉丝香气研究中的应用

目的 设计一款新型顶空固相萃取罐并考察验证其在传统川菜鱼香肉丝香气分析中的能力。方法 将新型顶空固相萃取罐与传统顶空进样瓶对比, 结合顶空固相微萃取技术和气相色谱-飞行时间质谱技术, 分析鱼香肉丝的香气组分。结果 本研究从鱼香肉丝中共分析鉴定出125种挥发性化合物, 包括23种含硫化合物、18种杂环化合物、16种醛类、12种醇类、9种酮类、9种羧酸类化合物等。两种取样装置得到的定性和定量结果存在明显差异: 有24种挥发性物质仅可通过新型顶空固相萃取罐检出, 63种化合物经新型顶空固相萃取罐检测的峰面积显著高于传统顶空进样瓶组(P<0.05), 且近80%挥发性物质的相对标准偏差均小于传统顶空进样瓶组。结论 本研究表明含硫化合物、羧酸类化合物、杂环化合物、醛类化合物对鱼香肉丝香气有重要潜在贡献, 新型顶空固相萃取罐密闭性可靠, 整体效果优于传统顶空进样瓶。本研究为鱼香肉丝等传统中式菜肴的香气分析和菜肴的标准化生产提供参考。     

超高压及热处理对中国沙棘原浆挥发性成分影响的比较

比较超高压及热处理对沙棘原浆挥发性成分的影响差异。沙棘原浆经500?MPa超高压30?℃处理15?min（处理组）,或90?℃热处理40?min（对照组）,采用顶空固相微萃取结合气相色谱-质谱联用技术分析处理对沙棘原浆挥发性成分的影响。结果表明,超高压处理可提高沙棘原浆中的挥发性成分,处理组的挥发性成分总含量高于对照组61%;处理组各类挥发性成分含量均与对照组存在显著差异,其中醇类和酯类的含量显著高于对照组;除酯类和酸类成分的种类低于对照组外,处理组其他挥发性成分的种类与对照组之间无差异。根据气味活性值大于0.2的原则,确定12?种对沙棘原浆香气贡献较大的组分,其中α-松油醇、己酸乙酯等10?种组分处理组高于对照组,壬醛和3-甲基丁酸处理组显著低于对照组。综上所述,超高压处理可显著提高沙棘原浆中的挥发性成分,其作用与促进底物释放,激活糖苷酶和酯酶分解结合态挥发性成分密切相关。     

Yeast derivatives (extracts and autolysates) in winemaking: Release of volatile compounds and effects on wine aroma volatility

A qualitative study of volatile compounds in three commercial yeast extracts and autolysates was performed by solid-phase microextraction-gas chromatography with mass spectrometric and olfactometric detection; their addition to white wines and their effect on wine aroma composition were investigated by analytical, olfactometric and sensory evaluations. More than 160 volatile compounds were detected in the headspace of the commercial powders (some not previously reported in literature), and their olfactory characters were described. Yeast derivatives strongly modified wine aroma composition, either affecting the volatility of wine aroma compounds or by releasing exogenous volatiles. Dosage appeared to be fundamental: low amounts increased the volatility of some esters, giving more flowery and fruity notes to the wine; higher amounts increased fatty acid content in the wine headspace, producing yeasty, herbaceous and cheese-like smells. Sensory tests demonstrated that yeast derivatives would not be suitable for wines with a typical varietal aroma.     

Effects of Different β‐D‐Glycosidases on Bound Aroma Compounds in Muscat Grape Determined by HS‐SPME and GC‐MS

Important “floral” aromas naturally occur in grapes predominantly as flavourless glycoconjugate precursors. Since these aroma compounds can be released by hydrolysis, different glycosidase enzymes can potentially contribute different aromas to wines. In this paper, we first established a procedure for profiling the free and bound volatile compounds in grape using GC‐MS combined with headspace solid‐phase microextraction (HS‐SPME). Comparison of the free and bound aroma compounds revealed that non‐volatile glycosides, known as aroma precursors, occur in high concentrations in musts. Among all compounds identified, 11 were fully quantified according to established standard calibration curves, while others were semi‐quantified. Using three different glycosidase enzymes, a total of 38 bound volatile compounds were identified in Muscat grape, including terpenes, higher alcohols, C‐6 compounds, and phenols, among others. The different enzymes had significant effects on the varietal aroma. Principal component analysis indicated that the characteristic aroma hydrolyzed by the commercial enzyme AR2000 was clearly different from that produced by other enzymes.     

湖北优良茶树品系绿茶香气成分分析

采用感官审评法和顶空固相微萃取法结合气相色谱-质谱联用技术,对6 个茶树品系所制绿茶的香气成分进行系统鉴定分析。结果表明,6 个茶树品系所制绿茶均具有鲜、清、高等典型的绿茶香气特征,其中01-4-7、20-2-1和03-7-1带有花香;共检出55 个香气成分,以醛类、醇类、酯类化合物为主,芳樟醇、壬醛、(Z)-己酸-3-己烯酯和香叶醇含量较高,其次是(E)-己-3-烯基丁酸酯、二甲硫、水杨酸甲酯、庚醛、癸醛等;不同茶树品系所制绿茶在香气物质含量上存在较大差异,部分样品存在一些含量较高的特异性香气成分;共得到9 个气味活度值相对较高的香气成分,依次为芳樟醇、癸醛、二甲硫、β-紫罗兰酮、香叶醇、壬醛、庚醛、(E)-2-壬烯醛、(Z)-己酸-3-己烯酯,对所测样品的香气形成贡献较大。多重分析表明：在香气成分上,6 个茶树品系与福鼎大白茶（对照）存在较大差异,其中茶树品系03-7-4、01-4-7、07-7-68和03-7-1所制绿茶的香气成分较为相似,20-2-1含有较高含量的酯类化合物且香气总量高,07-7-64有高含量的醛类化合物;关键变量分析表明有19 个香气成分是所测样品间的关键差异香气成分。     

闷黄对黄茶香气特征及关键香气化合物的影响

为明确闷黄对黄茶香气品质的影响,通过感官审评、顶空固相微萃取结合气相色谱-质谱联用技术和多元统计分析对3个茶树品种所制黄茶(有闷黄)和对照样(无闷黄)的香气特征和挥发性化合物组成开展研究。结果表明,与对照样相比,黄茶具有甜香风味。同时,黄茶中挥发性组分总含量是对照样的1.09～1.44倍,且醇类和烃类占比达到65.88%～76.93%。对挥发性化合物的主成分分析和层次聚类分析结果显示化合物组成体现了香气特征差异,进而可筛选出35种特征香气化合物(P<0.01)。正交偏最小二乘法判别分析进一步明确了闷黄影响的关键香气化合物14种(VIP≥1),其中具有花香、果香和甜香的α-松油醇、芳樟醇、γ-松油烯、柠檬烯、松油烯、苯乙酸甲酯、2,2,6-三甲基环己酮、4-氧代异佛尔酮和邻-异丙基苯在闷黄所制黄茶中含量明显高于对照样,这些化合物对黄茶呈现甜香的香气特征起到关键作用。     

应用GC-O和GC-MS分析酱香型习酒中挥发性香气成分

利用液液萃取法(LLE)提取酱香型习酒中的香气化合物,按照酸碱性将萃取组分分离,获得酸性/水溶性、中性、碱性三个组分,通过气相色谱-闻香法(GC-O)结合气相色谱-质谱(GC-MS)分别进行香气成分分析。在具有典型酱香特征的习酒中共检测出72种香气化合物,其中酸性组分29种,中性组分43种,碱性组分22种,14种香气化合物在两种或两种以上组分中均可检测到。研究发现酱香型习酒中主要的香气物质是酯类、醇类、挥发性有机酸、呋喃类、芳香族类、酚类、醛酮类、吡嗪类以及含硫化合物等。香气强度较大的物质有丁酸乙酯、己酸乙酯、1-丙醇、3-甲基丁醇、乙酸、3-甲基丁酸、糠醛、四甲基吡嗪和二甲基三硫,这些物质对酱香型习酒的风味贡献较大。     

戴尔有孢圆酵母与酿酒酵母混合发酵对猕猴桃酒香气的影响

用戴尔有孢圆酵母（Torulaspora delbrueckii SY-2-2）和酿酒酵母（Saccharomyces cerevisiae RV002）作为猕猴桃酒发酵菌株,以单接种酿酒酵母、单接种戴尔有孢圆酵母为对照组,同时接种戴尔有孢圆酵母和酿酒酵母、顺序接种戴尔有孢圆酵母和酿酒酵母为实验组,采用顶空固相微萃取法结合气相色谱-质谱技术测定猕猴桃汁发酵酒样产生的挥发性香气成分。结果表明,混菌发酵组获得的挥发性香气成分种类高于单菌发酵组,且顺序接种发酵组的香气成分种类（23 种）和质量浓度（336.95 mg/L）均最高。在顺序接种发酵组中,戴尔有孢圆酵母的参与提高了猕猴桃酒中挥发性物质的种类和含量,特别是苯乙酸乙酯、苯丙酸乙酯、苯乙醇、β-大马士酮、α-松油醇、桉树油醇等物质,赋予猕猴桃酒浓郁的花果香味,丰富了猕猴桃酒的香气成分。香气感官评价表明顺序接种发酵组的花香、草本香、甜香味更加浓郁,酒香和果香次之,整体评分最高。     

不同杏鲍菇菌株工厂化栽培子实体的挥发性风味成分分析及其香气评价

采用顶空固相微萃取和气相色谱-质谱联用技术鉴定不同杏鲍菇菌株工厂化栽培子实体中挥发性风味物质组成,结合电子鼻分析技术对不同杏鲍菇菌株栽培子实体的风味差异进行初步区分;并运用主成分分析（principal component analysis,PCA）明确对杏鲍菇子实体影响较大的挥发性风味成分,通过综合评价指标（general evaluation index,GEI）对不同杏鲍菇菌株栽培子实体的香气进行评价。结果表明,7 种杏鲍菇菌株子实体中共检测出102 种挥发性成分,主要包括醇类化合物、烯烃类化合物及酮醚类化合物等,共有成分达到36 种。电子鼻系统能够对7 种菌株的子实体风味进行差异区分。通过对主要挥发性风味物质的PCA发现,2-丁基-2-辛烯醛、3-辛酮、戊醇、丙酮、己醛、异戊酸甲酯、巯基乙醇、2,4-壬二烯醛、3-甲基丁醛、异戊醇对杏鲍菇子实体香气影响较大。GEI评价结果表明不同工厂化栽培的菌株子实体的香气差别显著,香气品质最优的为G.S.菌株。本研究为杏鲍菇育种和风味成分的开发利用提供一定的理论参考。     

Study of the volatile components of a candied plum and estimation of their contribution to the aroma

A methodology comprising the combination of sample analysis by simultaneous distillation and extraction (SDE) and headspace analysis by solid phase microextraction (HS-SPME) is proposed to characterise the volatile fraction and to estimate its contribution to the aroma properties of heat treated sugar-rich fruits. In the present study, the volatile composition of “Ameixa d’Elvas”, a traditional candied plum, was established by SDE. It reflects the complexity of the reactions and rearrangements that happen during the fruit ripening plus those occurring due to the thermal processing in presence of sucrose. HS-SPME allowed to detect the volatile compounds present in the headspace of the intact pulp, potentially responsible for the aroma properties. Eleven compounds were determined as the would-be impact odourants of “Ameixa d’Elvas”, which are associated with sweet, cooked, and fruity odours. All would-be impact odourants of “Ameixa d’Elvas” fruits, except one, were also detected in the sucrose syrup headspace where the fruits have been submersed. This study indicates that, together with the pulp of the processed fruit, syrup contains compounds that can contribute to the aroma of candied fruits.