基于GC-MS/GC-O结合PCA分析鉴定菊花精油特征香气成分

以7种不同厂家生产的菊花精油为对象,利用GC-MS和GC-O鉴定出菊花精油样品的特征香气物质。结果显示,菊花精油的特征香气物质主要为萜烯类、酯类、醇类、酮类、酸类以及醛类化合物等。对菊花精油样品做感官评价,并对其结果做PCA分析,得出影响菊花精油香气的主要感官属性为花香、木香、草香、果香和酸香。对比GC-O与PCA分析结果,解释特征香气物质对菊花精油整体香气的贡献。     

不同品种菊花涩味成分及其与唾液的相互作用

目的：了解不同品种的菊花茶品尝过程中涩味感知差异及形成机理。方法：选取5种不同品种的菊花作为研究对象,利用紫外—可见分光光度法对菊花中的主要呈涩味化学成分进行测定;利用电子舌智能味觉分析与传统感官评定相结合的方法,测定并评定5种不同品种菊花涩味感知强度;利用BCA法、SDS-PAGE法、考马斯亮蓝法等研究菊花中主要呈涩味化学成分与唾液的相互作用。结果：在5种菊花中多酚、黄酮含量最多的两种菊花为皇菊和亳菊,其相应的涩味特征值也最强,而多酚和黄酮类化合物的含量与茶汤的涩味强度呈较强的正相关。结论：作为主要呈涩物质,不同品种菊花茶中的多酚和黄酮类化合物的含量差异显著影响其涩味强弱,而菊花茶汤中的呈涩物质与唾液中的蛋白质结合并沉淀是产生涩味的主要原因之一。     

家鸽炖煮过程中营养物质及特征风味形成规律

为研究鸽汤营养及特征风味物质的释放规律,对不同加热时间(1、2、3 h)处理下的鸽汤营养物质及风味物质进行鉴定及对比分析。通过高效液相色谱和气相色谱-质谱联用方法鉴定主要风味物质及含量,结合电子鼻、电子舌结果评估鸽汤特征风味物质形成规律。随着煮制时间的延长,鸽汤中蛋白、脂肪以及总糖含量显著增加(P<0.05),煮制3 h时达到最大;电子舌结果表明鲜味和咸味为鸽汤的主要滋味特征;鲜味代表物质核苷酸的含量在煮制3 h时达到最大;GC-MS检测出鸽汤中共有67种挥发性化合物,包括醇类、烷烯烃类、醛类、酮类、酯类等,其中煮制1 h的鸽汤中挥发性化合物有17种,煮制2 h的鸽汤有36种,煮制3 h的鸽汤有34种。鸽汤中醛类和酮类物质的相对含量先增加后减少,煮制2 h的鸽汤挥发性风味物质中醛类和酮类物质的相对含量最高,戊醛、己醛、庚醛以及壬醛是鸽汤中的主要挥发性风味物质。不同煮制时间显著影响鸽汤中营养物质的含量,醛类物质是鸽汤中的主要挥发性风味物质,研究结果可以为开发营养全面的鸽汤风味煲及后续确定关键风味物质形成机制提供理论参考。     

GC-MS结合PCA探究不同加工方式对香梨汁风味品质影响

为探究不同加工方式对库尔勒香梨汁加工中其挥发性物质和感官品质的影响,采用静态顶空-气相色谱-质谱联用(HS-GC-MS)技术对不同加工方式下制备的香梨汁中的挥发性成分进行分离鉴定,并结合主成分分析技术对其挥发性成分与感官属性进行相关性分析。研究发现:果胶酶酶解和巴氏杀菌对香梨汁挥发性物质组成影响极为显著(p0.05),其中酯类物质丧失或显著降低,而醇类、烃类和杂环类物质则明显增多。果胶酶酶解和巴氏杀菌处理使香梨汁感官品质降低,巴氏杀菌使香梨汁异味和蒸煮味异常明显.结合主成分分析(PCA)分析得出,乙酸乙酯、己酸乙酯、丙酸乙酯、丁酸乙酯、己醇和壬醛与香梨汁的梨果香感官属性有很好的正相关性,乙酸己酯与香梨汁的花青香感官属性有很好的正相关性。     

8种饮用菊茶汤的感官风味与活性成分比较

本研究对杭白菊、福白菊、祁白菊、贡菊、亳菊、怀菊、滁菊、无菌菊等8种菊花茶汤的感官品质和活性成分进行对比。结合专业评价小组、高精度分光测色仪、顶空固相微萃取-气相色谱-质谱联用（HS-SPME-GC-MS）对菊花茶汤的感官品质、挥发性成分进行了分析。结果表明,根据所建立的描述性感官评价分析,8种菊花茶可被分为四类。建立汤色与色度值的关系为:黄绿色= ?32.274+0.324L*?0.564a*+0.084b*。利用偏最小二乘回归分析,确定了中药味与4-萜烯醇等6种物质相关、甜菜味与（e）-泰烯酮等13种物质相关、菜腥味与桃金娘烯醇等等14种物质相关。对总黄酮含量的分析表明,有机种植杭白菊中含量最高,祁白菊含量最低。通过超高效液相色谱（UPLC）分别在5种、7种、8种、4种和5种茶汤中检测出绿原酸、木犀草苷、木犀草素-7-O-β-葡萄糖醛酸苷、3, 5-O-二咖啡酰基奎宁酸、芹菜素-7-O-β-葡萄糖苷等活性成分,它们分别在祁白菊、贡菊、怀菊、祁白菊和福白菊中具有最高含量。     

不同干燥条件下福白菊菊花茶风味品质的比较分析

研究干燥工艺对福白菊菊花茶风味品质的影响。本实验采用气相色谱-质谱(gas chromatography-mass spectrometer,GC-MS)联用技术结合电子鼻对热风干燥、真空干燥和自然干燥的菊花茶进行风味成分解析,同时对比了3 种菊花茶的色泽、活性成分含量、抗氧化能力及感官等指标,为福白菊的精深加工提供参考。研究表明,3种加工工艺菊花茶中共有67种挥发性成分,真空干燥菊花茶中挥发性成分含量最高,自然干燥菊花茶挥发性成分的种类最多。电子鼻和GC-MS主成分分析结果显示3种菊花茶气味和挥发性成分差异显著。自然干燥菊花茶总酚、总黄酮含量最高,抗氧化能力最优,挥发性成分丰富、均衡,香气温和,口感宜人,但干燥效率低。真空干燥保持了福白菊花朵原有色泽和花香,菊花茶氨基酸含量高,气味浓郁,但口感欠佳。而热风干燥严重影响干燥福白菊花朵的颜色、型状和花香,对菊花茶的抗氧化成分和挥发性成分均有一定的破坏性,但干燥效率最高。     

茶汤滋味物质及其调控研究进展

滋味是茶汤的重要感官属性,滋味物质类型、含量及比例均影响着茶汤的品质,关于茶汤中滋味成分及其相互作用方面的研究目前较多,而且已有文献构建了一些改善茶汤滋味的方法。该文主要针对茶汤中滋味物质、滋味物质相互作用、影响茶汤滋味的因素和茶汤滋味调控等方面的研究情况进行了综述,为茶汤感官品质的改善提供借鉴。     

基于感官评价和气相色谱-质谱联用技术分析发芽糙米乳的挥发性风味特征

目的:利用GC-MS技术研究不同配方发酵糙米乳的挥发性风味物质组成,并结合感官评定指标评估发酵糙米乳的产品品质,以期对发芽糙米乳新产品的开发及感官品质提升,提供理论依据。方法:选用不同配方的发芽糙米乳,采用气相色谱-质谱联用技术对发芽糙米乳产品的挥发性风味物质进行测定,经偏最小二乘回归法对感官属性与挥发性风味物质成分做相关性分析。结果:经GC-MS分析并通过数据库检索结合质谱信息比对,筛选得到21种挥发性风味物质。结论:2,3-丁二酮、乙偶姻、2,3-戊二酮、1-庚醇和乙酸分别与奶香味、米香味和酸味呈显著相关,是发芽糙米乳的主要风味物质。     

基于游离氨基酸、挥发性组分和感官评价的2 种酸化技术加工乳饼的滋味特征差异分析

为明确传统酸水乳饼和发酵型乳饼的特征呈味物质,利用氨基酸分析仪和气相色谱仪分别对传统酸水乳饼和发酵型乳饼中的特征呈味物质（游离氨基酸、游离脂肪酸）进行测定,采用滋味活度值（taste activity value,TAV）判定特征呈味物质,同时进行感官评价;并且结合游离氨基酸和挥发性成分分析特征呈味物质与感官属性之间的相关性。结果表明,谷氨酸、组氨酸和癸酸、月桂酸、肉豆蔻酸、油酸、亚油酸的TAV大于1,对乳饼的滋味有着重要贡献。在感官和呈味物质组成方面,2 种工艺加工的乳饼明显区分开。发酵型乳饼的总体滋味强度高于传统酸水乳饼（P＜0.05）,感官属性以酸味、甜味、苦味和鲜味为主,而传统酸水乳饼伴有不愉悦的异味。偏最小二乘法对特征呈味物质与感官属性之间的相关性分析表明,感官属性与游离氨基酸相关性高,传统酸水乳饼的咸味与精氨酸,异味与甘氨酸、癸酸和棕榈烯酸呈显著正相关（P＜0.05）;发酵型乳饼的酸味与硬脂酸和亚油酸,甜味与天冬氨酸、苏氨酸、丝氨酸、谷氨酸、丙氨酸以及亚油酸,苦味与缬氨酸、蛋氨酸、异亮氨酸、亮氨酸、酪氨酸以及肉豆蔻酸,鲜味与天冬氨酸、谷氨酸、丙氨酸均呈显著正相关（P＜0.05）。发酵酸化技术促进蛋白质和脂肪的分解,改善乳饼的滋味。     

Effects of the cultivation period of sweet potato on the sensory quality of imo‐shochu,a Japanese traditional spirit

Imo‐shochu is a Japanese traditional spirit made from sweet potatoes. Characteristic volatile compounds in imo‐shochu are mainly derived from the sweet potato and its flavour significantly depends on the quality and cultivar of sweet potato used. Thus, the effects of the cultivation period of sweet potatoes on sensory characteristics and composition of volatile compounds of imo‐shochu were investigated. Sweet potatoes (cv. Koganesengan) used in this study were harvested at 120, 150 or 180 days after planting, and each sample was used to prepare imo‐shochu. The imo‐shochu samples were evaluated by eight panellists in a blind study, who ranked them on the basis of various odour and taste attributes. Rank sums were calculated and data were analysed using the Friedman test. The compositions of the volatile compounds in the imo‐shochu samples were analysed using gas chromatography–mass spectrometry (GC‐MS). Sensory evaluations showed that a longer cultivation period of the sweet potatoes enhanced the floral aroma and characteristic taste of imo‐shochu. In addition, imo‐shochu prepared with the sample cultivated for 150 days was evaluated to have a sweeter taste than that prepared with the other samples. The GC‐MS analysis showed that imo‐shochu prepared with the sample cultivated for 180 days contained a lower concentration of monoterpene alcohols, but higher concentrations of β‐damascenone, rose oxide, and fatty acid esters than the imo‐shochu prepared with the sample cultivated for 120 days. These differences in the composition of the volatile compounds affected the sensory qualities of the imo‐shochu. Copyright © 2016 The Institute of Brewing & Distilling     

Composition of volatile compounds in bovine milk heat treated by instant infusion pasteurisation and their correlation to sensory analysis

Volatile compounds in skim milk and nonstandardised milk subjected to instant infusion pasteurisation at 80°C, 100°C and 120°C were compared with raw milk, high temperature short time pasteurised milk and milk pasteurised at 85°C/30 s. The composition of volatile compounds differed between infusion pasteurisation treated samples and the reference pasteurisations. The sensory properties of skim milk subjected to instant infusion pasteurisation were described by negative attributes, such as cardboard sour and plastic flavours, which are not associated normally with fresh milk. Partial least squares modelling showed good correlation between the volatile compounds and the sensory properties, indicating the predictive and possible causal importance of the volatile compounds for the sensory characteristics.     

Changes in salted yoghurt during storage

The study was conducted to determine the gross chemical composition and concentrations of free fatty acids (FFAs) and volatile compounds of salted yoghurt made from indigenous goat's milk. The effects of some chemical properties on sensory attributes of salted yoghurt were also studied. Changes in FFAs (P < 0.01) and volatile compounds were statistically significant (P < 0.05) during storage. The most abundant FFAs were 9‐octadecenoic (C_18:1), hexadecanoic (C₁₆), tetradecanoic (C₁₄) and decanoic (C₁₀) acids, respectively. Ethanol and ethyl acetate were principal volatile compounds through the end of storage period. The storage period affected the intensity of flavour attributes and overall flavour score of salted yoghurt (P < 0.05). According to factor analysis result, chemical compounds including volatiles, FFAs up to C₁₄, tyrosine and titratable acidity, and flavour attributes explained 86.50% and 55.33% of total variance, respectively.     

Volatile components and sensory properties of jujube wine as affected by material preprocessing

Fermented jujube wine, derived from the red jujube berry, has a unique flavor, a mild and sweet taste, and high nutritional value. Among diverse varieties of jujube, Bokjo and the native variety are the most frequently cultivated varieties in Korea. The present study aimed to determine the brewing properties of jujube and to compare the characteristics of fresh and dried fruits of the native and Bokjo varieties for optimal brewing conditions for jujube wine production. We investigated the physicochemical and sensory properties, and we compared the volatile compounds in jujube wine prepared using different methods, through solid-phase microextraction (SPME) GC/MS analysis. The physicochemical properties of jujube wine depended on the drying process rather than the cultivar or the presence of seeds. Sensory properties including aroma and sweetness, which have positive effects on jujube wines, were greater in the whole dried fruit group, while negative properties including grassy aroma, sourness, and bitter taste, were high in the fresh fruit group; these observations contrast their physicochemical properties, as analyzed using dried jujube with seeds. Significant differences were observed in volatile compounds among jujube wine samples. In particular, isoamyl octanoate, isoamyl decanoate, ethyl laurate, ethyl myristate, and 2-phenethyl acetate potentially contribute to the jujube-like flavor of dried jujube wine. These results could be useful as basic data for raw material processing for jujube wine production.     

The relationship between sensory quality and volatile compounds in raw juice processed from elderberries (Sambucus nigra L.)

Elderberry juice was processed by pressing of 101 samples of elderberries (Sambucus nigra L.) picked in Austria, England and Denmark at optimum maturity. Taste panels trained in determination of elderberry flavour evaluated the juices and the results from the sensory evaluation were correlated to the content of volatile compounds. The volatile compounds were isolated from elderberry juices by dynamic headspace technique and analysed by GC-FID and GC-MS. A total of 59 volatile compounds were identified, 9 of which have not previously been detected in elderberry products. A total of 53 compounds occurred in quantifiable amounts and significant differences among the investigated elderberry samples were observed for 50 compounds. The importance of the isolated volatile compounds to elderberry flavour was determined by classical factor analysis using the results from the sensory evaluation and information on the odour of the individual volatile compounds. Classical factor analysis were used including determination of eigenvalues, factor loadings and factor scores by varimax rotation of standardised variables for extraction of four non correlated factors (principal components) explaining approximately 73% of the variation in elderberry flavour. Twenty-eight volatile compounds and sensory quality were included in the four factors. Using the compounds with highest numerical values (loadings) the four factors were named: fresh-elderberry-elder flower (35.2%), fresh-fruity-sweet (17.3%), fresh-fruity (13.7%) and green-floral-fruity (6.7%). Three compounds with characteristic elderberry odour (-damascenone, nonanal, dihydroedulan) were closely correlated with the sensory quality of elderberry together with compounds with fruity, floral, green and/or miscellaneous odours.     

Prediction of Sensory Profile of Mango Using Textural Attributes During Ripening

Mango is an important commercial fruit and is marketed based on their colour, firmness and taste. These sensory parameters vary with individual mango and person involved in testing. There is little or no information available on the instrumental estimation of these sensory attributes. The present study, therefore, was conducted to correlate sensory and instrumental textural attributes to explore the possibility of predicting them for seven major cultivars of mango influenced by harvesting dates and ripening period (10 days). In general, the textural property of peel, pulp and fruit decreased while sensory attributes increased during fruit ripening. Sensory qualities like taste, flavour and overall acceptability were significantly affected by harvesting date, cultivar and ripening period. Harvesting time and cultivars, however, did not influence the fruit appearance. Among textural attributes, peel firmness was closely associated with all the sensory parameters indicating that textural parameters could be useful to predict sensory profile of mango cultivars during their ripening. Cultivar-specific variations were observed while evaluating various equations (linear/polynomial/exponential/logarithmic/power) for correlating their textural and sensory attributes. Polynomial equation was found to be the best fit (highest coefficient of determination, R ²) for prediction of sensory quality using textural properties of majority of mango cultivars. All cultivars under study except Alphonso collected from Maharashtra showed R ² value above 0.911 which indicated potentiality of the fitted equations for the prediction of sensory attributes using textural characteristics of mango.     

Analysis of flavor volatile compounds by dynamic headspace in traditional and hybrid cultivars of Spanish tomatoes

A system specifically designed for the non-destructive analysis of volatile organic compounds in fresh tomatoes, based on a dynamic headspace technique, has been set up to quantify the volatile aroma constituents of tomato fruits. This system will reduce the high variability associated to sample selection in post-harvest studies. Volatile compounds with a major contribution to aroma have been quantitatively determined in two traditional tomato cultivars and one commercial F1 hybrid. One of the traditional cultivars, “De la Pera,” got the highest values of odor and aroma in sensory tests performed using a trained panel of 10 assessors. The same cultivar showed significantly higher contents of all eight volatile compounds studied (hexanal, trans-2-hexenal, cis-3-hexenol, 1-hexanol, 1-nitro-3-methylbutane, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, and β-ionone). Significant differences among traditional and hybrid tomato cultivars can be detected for volatile compounds, thus allowing the use of volatile determination as a possible tool in tomato breeding programs.     

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.