Aroma characterization of red wines from cv. Bobal grape variety grown in La Mancha region

Bobal is an indigenous Spanish cultivar, principally grown in the region of Valencia. The volatile composition of young red wines made from the cv. Bobal grape variety grown in the La Mancha region of Spain has been studied over five vintages by instrumental analysis to determine the influence of grape variety on the aroma of wine. Free and glycosidically-bound aroma compounds were isolated by solid phase extraction (SPE) using dichloromethane and ethyl acetate respectively to later be analyzed using gas chromatography-mass spectrometry (GC/MS). One hundred and twelve (112) free aroma compounds and ninety-six (96) bound aroma compounds were identified and quantified in Bobal wines oven this five year period. Based on the result, Bobal wine presents a complex chemical profile with a wealth of aromas in its aromatic composition.     

EFFECT OF COOKING METHOD ON THE AROMA CONSTITUENTS OF SWEET POTATOES [IPOMOEA BATATAS (L.) LAM.]

To better understand the factors controlling the flavor of horticultural products, the effect of method of cooking on the volatile flavor of sweet potatoes was assessed. Volatile extracts from sweet potatoes cooked by baking, boiling, and microwaving were studied by GC, GC‐MS and GC olfactory assessment. GC‐olfactory analysis identified 37 compounds that were odor‐active, 36 of which were identified. Compared with conventional baking, boiling and microwaving yielded only 54.26% and 6.43% of the relative total yield of aroma‐active compounds, respectively. From aroma extract dilution analysis, four compounds contributed to the aroma from each cooking method. In addition, cooking method specific aroma contributing compounds accounted for the unique aroma of each of the cooked products. Thus the flavor of cooked sweet potatoes is dependent upon the method of cooking both on a sensory and chemical level.     

炒青和烘青绿茶香气的对比分析

首次采用柱吸附装置提取了炒青和烘青绿茶茶汤的顶空香气,经气相色谱／质谱（GC／MS）分析了二者香气在组成和含量上的差别。结果表明,炒青和烘青绿茶香气组分之间差异小,而在香气组分的相对含量上差异较大,这是形成二者各自不同香型特点的主要原因。     

Comparison of volatiles in raw and boiled potatoes using a mild extraction technique combined with GC odour profiling and GC–MS

Aromas of raw and boiled potatoes were compared using a mild extraction technique, ensuring preservation of the very labile composition of potato aroma during analysis. The extracts were evaluated by GC–MS and GC-sniffing using a panel of four judges. A total of 29 compounds were identified by GC–MS in raw potatoes and 25 in boiled. Twenty compounds were found in both raw and boiled potatoes, but most often in very different concentrations. During GC-sniffing, 33 odours were detected in boiled, and 27 in raw potatoes. Eight odours corresponded to compounds identified by GC–MS. Another four odours could be tentatively identified. It is concluded that the change in aroma during boiling of potatoes depends on compounds from lipid oxidation as well as compounds from other types of reactions, for instance the Strecker-degradation.     

3种酵母对贵人香干白葡萄酒香气的影响

本文采用顶空固相微萃取结合气相色谱与质谱联用(GC/MS)技术,研究了LVCB、FW和QA23酵母对贵人香干白葡萄酒香气的影响.结果表明,3种酵母发酵的贵人香干白酒中主要香气的组成基本相似,但不同香气物质含量存在差异.酵母LVCB和FW的产酸、产酯能力以及总体产香性能要优于酵母QAE3;酵母FW总体产醇能力最差;与FW发酵的干白葡萄酒相比较,LVCB发酵的葡萄酒中酯类总量较低,但主要的酯类物质含量差异不明显.研究结果为不同香型葡萄酒的酿造提供了有用的信息.     

Insoluble Grape Material Present in Must Affects the Overall Fermentation Aroma of Dry White Wines Made from Three Grape Cultivars Cultivated in Greece

ABSTRACT: Musts from 3 grape varieties were used to elucidate the effect of the presence of grape solids in must on the volatile composition of the resultant white wines. Volatile compounds were analyzed by GC/MS and GC/FPD except H₂S, which was measured spectrophotometrically. Increasing quantities of grape insoluble material decreased the substances that enhanced aroma of Savatiano and Batiki wines. Simultaneously, the levels of compounds that degrade wine aroma, when formed in large amounts, were increased. However, in Muscat of Hamburg wines, the levels of some volatiles were not influenced by must turbidity in the same way as in wines of the other cultivars.     

Characterization of the differences in the aroma of cherry wines from different price segments using gas chromatography–mass spectrometry,odor activity values,sensory analysis,and aroma reconstitution

The aroma composition, aroma-active compounds, and sensory attributions of cherry wines from three different price segments were investigated. A total of 48 aroma compounds were identified and quantified using headspace solid-phase microextraction (HS-SPME)/gas chromatography–mass spectrometry (GC–MS), among which 23 aroma compounds were further screened out as important odorants based on their odor activity values (OAVs); then, the previously mentioned 23 volatiles were correlated to sensory attributes using partial least-squares regression (PLSR). The result indicates that the differently priced wines were associated with different compounds and aroma attributions. Finally, aroma reconstitution was performed by mixing odor-active aroma compounds (OAVs>1) on the basis of their measured concentrations in the original sample. The result indicated that the aroma profile of the reconstituted sample was similar to that of the original sample.     

Effect of Maceration Time on Free and Bound Volatiles of Red Wines from cv. Karaoğlan (Vitis vinifera L.) Grapes Grown in Arapgir,Turkey

Skin maceration is an essential winemaking technique that affects sensory properties and aroma of red wines. The aim of this study was to investigate aroma profiles of red wines made from cv. Karao?lan, a grape variety grown in Arapgir (Malatya, Turkey) and the effect of maceration time (5, 10, and 15 d) on free and bound aroma compounds and sensory properties. Three maceration times were applied in durations of 5, 10, and 15 d. Free and glycosidically bound aroma compounds were analyzed using gas chromatography‐mass spectrometry (GC‐MS) in Karao?lan wines, and the effect of different maceration times on aroma composition were evaluated. Results indicate that extended maceration time significantly influenced the aroma composition of wines both qualitatively and quantitatively. A total of 59 free and 22 bound aroma compounds were identified in the final wines. The maximum of free aroma content was achieved with 5 d of maceration, while 15 d of maceration gave the highest amount of glycosidically bound aroma compounds. From sensorial point of view, the wine produced with 10 d of maceration had the best panel score compared to wines with 5 and 15 d of maceration. This is the first study referring to the composition of aroma compounds of red wines made from cv. Karao?lan. It was concluded that this cultivar resulted in a good quality wine in terms of bound and free aroma compounds. This information of vinification practices that influence the chemical properties of wine is useful for grape growers and winemakers.     

杀青方式对绿茶鲜汁饮料香气的影响

应用GC-MS技术对不同杀青方式处理的杀青叶的香气组分以及含量进行了分析。结果表明:微波杀青叶挥发性成分的总量为59.29%,明显高于烘青绿茶以及滚筒杀青、蒸汽杀青2种杀青叶,尤其是在绿茶香气形成过程当中起关键作用的高级脂肪醇、萜烯醇、酮类和酯类含量较高,微波杀青叶的香气组成较滚筒杀青叶和蒸汽杀青叶更为接近烘膏绿茶。采用微波杀青叶生产绿茶鲜汁饮料可有效改善饮料的香气品质。     

Fatty acid profiling of bovine milk and cheese from six European areas by GC‐FID and GC‐MS

The fatty acid (FA) composition of milk from six European areas, as well as the alteration in the FA profile during cheese production, was studied using both a targeted GC‐FID and an untargeted GC‐MS approach. By applying principal component, partial least square discriminant and chemical similarity enrichment analysis, a discrimination of the geographical areas could be achieved highlighting important FA classes such as odd‐ and branched‐chain FAs for the differentiation. The FA profile remained constant during cheese production, and aroma compounds have been identified as biomarkers for the ripening methods used, namely foil and smear ripening.     

SDE and SPME Analysis of Flavor Compounds in Jin Xuan Oolong Tea

Simultaneous distillation‐extraction (SDE) and solid phase micro extraction (SPME) are procedures used for the isolation of flavor compounds in foods. The purpose of this study was to optimize SDE conditions (solvent and time) and to compare SDE with SPME for the isolation of flavor compounds in Jin Xuan oolong tea using GC‐MS and GC‐O. The concentration of volatile compounds isolated with diethyl ether was higher (P < 0.05) than for dichloromethane and concentration was higher at 40 min (P < 0.05) than 20 or 60 min extractions. For SDE, 128 volatiles were identified using GC‐MS and 45 aroma active compounds using GC‐O. Trans‐nerolidol was the most abundant compound in oolong tea. The number of volatiles identified using GC‐MS was lower in SPME than SDE. For SPME, 59 volatiles and 41 aroma active compounds were identified. The composition of the volatiles isolated by the 2 methods differed considerably but provided complementary information.     

Aroma release of a model wine solution as influenced by the presence of non-volatile components. Effect of commercial tannin extracts, polysaccharides and artificial saliva

The effect of commercial tannin extracts, extracted either from grape seeds or grape skins, a natural wine polysaccharide extract, pectin and arabinogalactan on the headspace release of selected aroma compounds from a “model wine” solution was investigated. Changes in the volatility of the aroma compounds were studied using headspace solid-phase microextraction combined with GC/FID. The performance of four commercially available fibre coatings was checked and the 50/30 ??m DVB/CAR/PDMS one was proved to be the most effective. A short sampling time (1 min) was used to determine the “true” headspace concentration at equilibrium between the headspace and the sample. In general, the volatility of the studied aroma compounds appeared to be correlated to increasing tannin levels as well as to their origin. The volatility of esters was generally increased upon tannin addition at low concentrations, while at higher addition levels the two extracts exhibited dissimilar behaviour attributed to their different composition. Both arabinogalactan and pectin addition at low concentrations increased the volatility of the studied aroma compounds, while at higher concentrations pectin exhibited a different behaviour by salting out hydrophobic compounds in the vapour phase. In addition, grape skin and seed tannin extracts in admixture with polysaccharides either prevented the macromolecular chains to associate with volatile molecules or led to additional flavour retention depending on the aroma compound and the addition level. Saliva addition enhanced the volatility of the most hydrophobic compounds whereas the hydrophilic compounds were retained into the matrix.     

GC/O技术在白酒特殊气味来源研究中的应用

GC／O（gas chromatography—01factometry）技术是一种将气相色谱和人体感官相结合的分析方法,主要应用于各种食品的气味分析。介绍了GC／O的工作原理和分析方法,着重介绍了利用GC／O技术研究白酒的特殊气味成分,该技术将在中国白酒的气味活性物质研究和白酒生产研究中发挥更大的作用。     

Trehalose improves flavour retention in dehydrated apricot puree

The influence of the addition of two sugars (trehalose and sucrose) on the retention of volatiles responsible for the characteristic aroma in dehydrated apricot puree was studied. Aroma compounds of fresh and both freeze‐dried and foam‐mat‐dried apricot puree were analysed by manual headspace solid‐phase microextraction coupled with gas chromatography (GC‐FID and GC‐MS). The best retention of aroma compounds in dehydrated apricot puree was obtained when trehalose was added, regardless of the dehydration process used (freeze drying or foam‐mat drying), although, generally, a much higher retention of flavour volatiles was obtained in freeze‐dried purees. Principal Component Analysis and Cluster Analysis were applied to all the apricot purees studied to obtain a simplified view of the relationship among the aroma compounds in dehydrated apricot purees. This study gives further insights into the mechanisms that occur when trehalose is applied as an additive and will enable the development of new processes to maximize this effect and to produce superior dried products.