Ethyl Decanoate Research Articles

Volatile and phenolic profiles of traditional Romanian apple brandy after rapid ageing with different wood chips

The aim of this work was to find differences in the volatile and phenolic profiles of the traditional Romanian apple brandy pălinca aged with various species of wood chips. Seven types of wood species, two types of oak (Quercus petraea and Quercus robur), plus sweet chestnut, mulberry, walnut, fir and cherry, were considered. The majority of volatile compounds characterizing the aroma profile of pălinca were esters, particularly ethyl esters, with ethyl isobutyrate, ethyl isovalerate, ethyl caproate, ethyl octanoate and ethyl decanoate as the most abundant. The most important source of catechin was cherry wood. Rutin and juglone were solubilised only in walnut wood aged brandy. Vanillin, increased significantly in chestnut aged apple brandy. Given the cost and difficulty in handling wooden barrels, and as an alternative being able to select from a range of specific wooden chips, this work could potentially guide actors in beverage industry to less expensive alternatives.

Biotransformation of green tea (Camellia sinensis) by wine yeast Saccharomyces cerevisiae.

Wine yeast Saccharomyces cerevisiae 71B was used in fermentation of green tea to modulate the volatiles and nonvolatiles. After fermentation, higher alcohols, esters, and acids, such as isoamyl alcohol, isobutanol, ethyl octanoate, ethyl decanoate, octanoic, and decanoic acids were generated. Some key aroma compounds of tea including linalool, hotrienol, dihydroactinidiolide, and 2-phenylethanol increased significantly. Among these compounds, linalool and 2-phenylethanol increased by 1.3- and 10-fold, respectively, which impart floral and fruity notes to fermented green tea. Alkaloids including caffeine, theobromine, and theophylline were reduced significantly after fermentation, while the most important free amino acid in tea, theanine, was not metabolized by S. cerevisiae. Tea catechins decreased whereas gallic and caffeic acids increased significantly, resulting in the unchanged antioxidant capacity of the fermented green tea. Hence, this work highlighted the potential of using S. cerevisiae to modulate green tea aroma and nonvolatiles. PRACTICAL APPLICATION: A novel fermented tea is produced by yeast fermentation. Saccharomyces cerevisiae led to significant changes in tea volatiles and nonvolatiles. Antioxidant capacity remained stable after fermentation.

Volatile Compounds of Homemade Grape Brandy Determined by GC-MS Analysis

The aim of this paper was to determine whether the addition of some ingredients to the same grape brandy after distillation affects the chemical composition of the volatile components by applying the gas chromatography coupled with mass spectrometry (GC-MS). Five samples were subjected to this study and a total of 57 compounds were identified. For all examined samples, esters were the most dominant class of compounds, but in different proportions. Ethyl decanoate was the most abundant compound in the sample L1 (grape brandy kept in an oak barrel) with the contribution of 29.1%, followed by ethyl octanoate (17.2%) and ethyl dodecanoate (14.8%). Sample L2 (grape brandy with summer truffles) was dominated by n– hexanol and ethyl lactate with similar contribution (18.1% and 17.8%, respectively). On the other hand, in the sample L3 (grape brandy with winter truffles) ethyl lactate was present with the contribution 44.8%. The dominant compounds in sample L4 (grape brandy with grains of coffee and dried grapes) were ethyl decanoate with contribution of 14.8% and phenyl ethyl alcohol (12.5%), while the two main volatiles of the sample L5 (grape brandy with young green walnuts) were diethyl succinate (22.9%) followed by ethyl lactate (21.9%). The results obtained in this study on volatile aromatic compounds in the analyzed grape brandies suggest that addition of some ingredients to the same grape brandy after distillation affects the chemical composition in both the number of aromatic compounds and their relative content.

Aroma profiles of commercial Chinese traditional fermented fish (Suan yu) in Western Hunan: GC-MS, odor activity value and sensory evaluation by partial least squares regression

ABSTRACT In this study, the aroma volatile compounds of commercial Chinese traditional fermented fish (Suan yu) from western Hunan were investigated. A total of 59 volatile compounds were identified and quantified by GC-MS combined with headspace solid-phase microextraction. Esters and alcohols presented over 50 percent of the overall aroma in concentration. With the calculation of odor activity values (OAVs), 20 odorants were recognized as aroma-active compounds due to their OAVs greater than 1, including esters (10), alcohols (5), acids (1), and aldehydes (4). Sensory evaluation revealed higher scores in estery, fruity, and grassy attributes than others. A positive correlation between sensory attributes and aroma-active compounds was clearly elaborated by partial least squares regression analysis (PLSR). PLSR results indicated that ethyl-2-methylbutyrate, ethyl 3-methylbutyrate, and ethyl decanoate were significantly and positively correlated with fruity attribute, while ethyl hexanoate and 1-octen-3-ol had a significant positive impact on estery and grassy attribute, respectively. This study elaborates the aroma profile of Suan yu from western Hunan of China, and implies the availability of PLSR for the flavor evaluation of fish products.

A group contribution method to predict the thermal conductivity of fatty acid methyl esters and fatty acid ethyl esters components of biodiesel

Recently, biodiesel is considered as a potential alternative fuel in internal combustion engines, because of their beneficial effects on pollution emission and engine performance. In this work, a group contribution method (GCM) to predict the thermal conductivity of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) components of biodiesel as a function of the temperature (290 K to 350 K) is presented. Nearly 120 experimental thermal conductivity data points at different temperatures compiled for nine esters (methyl hexanoate, methyl octanoate, methyl pelargonate, methyl decanoate, ethyl valerate, ethyl valerate, ethyl heptanoate, ethyl octanoate, ethyl decanoate) were used for presenting and optimizing the formula. Additionaly, 51 experimental data points compiled for four esters (methyl myristate, methyl laurate, ethyl myristate and ethyl laurate) were employed to validate the model parameters, and the maximum and average absolute deviation are 0.61% and 1.97%. It is evident that the new proposed GCM models to predict the thermal conductivity of FAMEs and FAEEs are with high accuracy.

Physicochemical, aromatic and sensory properties of the ‘Riesling Italico’ wines fermented with Saccharomyces and non-Saccharomyces yeasts

ABSTRACT: The sensory quality of wines is affected by the compounds produced by the action of the yeasts used in alcoholic fermentation. This work aimed at assessing the physicochemical, aromatic and sensory properties of the ‘Riesling Italico’ white wines produced by using the Saccharomyces and non-Saccharomyces yeasts. The yeasts S. cerevisiae, S. cerevisiae cerevisiae, S. bayanus, Torulaspora delbrueckii and Metschnikowia pulcherrima were inoculated individually into the must. For 10 days, the alcohol was left to ferment in 7 L carboys in triplicate, at 15º C temperature. The standard physicochemical analyses were done and the quality of the wines was determined. The volatile compounds were identified and quantitative descriptive sensory analyses were performed. All the yeasts produced wines with the characteristic alcohol, volatile acidity and residual sugar content as stipulated by the Brazilian legislation. The T. delbrueckii yeast produced high-content phenylethyl acetate, isoamyl acetate and ethyl decanoate wines, of superior olfactory quality and sensory rating.

Sensory descriptive and comprehensive GC-MS as suitable tools to characterize the effects of alternative winemaking procedures on wine aroma. Part II: BRS Rúbea and BRS Cora

The present manuscript assessed the volatile and sensory profiles of BRS Rúbea and BRS Cora wines elaborated from traditional, grape pre-drying and submerged cap winemaking. The wines contained a higher concentration of acetates (257 mg L−1 to 547 mg L−1) and ethyl and methyl esters (183 mg L−1 to 456 mg L−1) in comparison with Vitis vinifera wines. PCA was applied (explaining 68.43% of the total variance), and the higher concentration of ethyl decanoate and ethyl octanoate, diethyl succinate, hydroxylinalool, and 2-phenyl ethanol was responsible for describing the BRS Rúbea wines as fruity/foxy. They also presented an intense jam note, probably due to their higher concentration of syringol and guaiacol. BRS Cora wines exhibited a vegetal note, possibly due to their higher concentration of 1-hexanol and cis-3-hexenol. Wines from pre-dried grapes presented higher concentration of furfural, assuming a bitter/burned almond aroma. Alternative winemaking accounted for suitable changes in wine aroma, enhancing wine quality.

Influence of Glutathione and Ascorbic Acid Treatments during Vinification of Feteasca Regala Variety and Their Antioxidant Effect on Volatile Profile.

Volatile profiles were determined for white wines of Feteasca regala variety produced from musts in which the antioxidants glutathione and ascorbic acid were added in different proportions before inception of alcoholic fermentation. Treatments with these antioxidants affect some volatile compound evolution and positively influence the wine volatile profile. After one year of storage in bottles with and without carbon dioxide protection the volatile profiles of the wines were assessed by using a Fast GC Alpha MOS Heracles e-Nose by applying a DFA multivariate statistical method and AroChemBase database for compound identification. The analyses showed that some higher alcohols, such as 2-phenylethanol and 2-methyl-1-butanol were in lower concentrations in wines treated with reduced glutathione, while the main ethyl fatty acid esters, such as ethyl butanoate, ethyl hexanoate, ethyl octanoate, and ethyl decanoate were better preserved when higher concentrations of any of the antioxidants were added in must. On the other hand, it was observed that some other volatile compounds were not affected by these applied treatments.

THE IMPACT OF THE FERMENTATION CONDITIONS ON THE ESTER PRODUCING CAPACITY OF DIFFERENT SACCHAROMYCES CEREVISIAE STRAINS AND THE ORGANOLEPTIC PROFILE OF CABERNET SAUVIGNON WINES

The ester producing capacity of two strains of Saccharomyces cerevisiae was investigated, depending on the alcoholic fermentation conditions of grape pulp from Cabernet Sauvignon variety. The influence of the temperature (20°C, 24°C, 28°C) and the inoculum amount of yeast culture (2%, 3%, 4%) on the total esters synthesized during the process was monitored. Neural networks were implemented and mathematical models were derived, adequately describing the fermentation processes at the combination of grape variety – yeast strain – conditions. The results of gas chromatographic analysis identified methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, isoamyl acetate, amyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate in the wines. It was found that the impact of esters produced by the yeasts on the organoleptic profile of the wines was not because of their total amount but mainly due to the ratio between the individual representatives. Under the experiment conditions the strain Saccharomyces cerevisiae 8-11, fermented at 28°C, with 3% inoculum yeast culture was identified as more suitable for the production of Cabernet Sauvignon wines.

Development of polydimethylsiloxane-microdiamond composite materials for application as sorptive devices

The development and application of non-porous and porous sorptive rods, comprised of polydimethylsiloxane–microdiamond (PDMS-MD) composites, is reported. The PDMS-MD composites were made porous using inorganic salt (NaCl and NaHCO3) particles as dissolvable templates. Materials with pore size of ~40 µm down to ~5 µm were produced. The advantages of incorporating up to ~60%microdiamond (2–4 µm) into PDMS included: (1) significant increase in the density, which saw the rods sink within the aqueous sample without addition of secondary metal or glass materials, (2) significant improvement in mechanical stability (the porous composite rods could be thermally treated multiple times before application, unlike porous PDMS), (3) increased thermal stability up to 450–500 °C with only 6% weight loss of volatile components, and (4) higher thermal conductivity, estimated to be 108% higher than for PDMS. The PDMS-MD investigated as a sorbent for extraction, followed by liquid desorption and GC-FID analysis. Recovery of the sorbent for test solutes, isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, and phenethyl acetate, was found to range from ~87% to >100, with RSD of 2.10–12.50% in synthetic wine samples. Non-porous composite rods provided similar % recoveries to a commercial sorptive device (PDMS Twister), whereas porous rods showed improved % recovery for most of the test solutes (>10–20%) when applied under similar conditions. The limits of detection (LOD) for the above solutes within the developed method ranged from 0.60 to 27.30 µg L−1). Application of the PDMS-MD-LD-GC-FID method to white wine samples demonstrated how the PDMS-MD composite material can be applied as a robust and an efficient sorptive phase for trace chemical analysis.

Effect of saliva composition and flow on inter-individual differences in the temporal perception of retronasal aroma during wine tasting.

In order to determine if inter-individual differences in saliva composition and flow influence the perception of specific aromatic stimuli elicited by esters after wine consumption, ten individuals were selected and instructed in the recognition of four aromatic stimuli elicited by four ester compounds, which were added to a rosé wine. The whole panel was firstly characterised by their salivary flow, composition (pH, total protein content, macro- and micro- minerals) and rheological properties (viscosity), and secondly, the panellists were trained in a dynamic sensory method for the evaluation of retronasal aroma intensity at discrete time intervals (5, 60, 120, and 180 s) after wine expectoration. Significant inter-individual differences (p < 0.05) in saliva composition were found in most salivary parameters. Differences in the intensity ratings among individuals were also found for the four aroma attributes. Spearman correlation analysis between saliva parameters and aroma intensity over time showed a strong positive correlation between salivary flow and aroma perception for some aroma and time points. This correlation was higher in the immediate than in the long lasting perception and greater for aroma attributes elicited by short chain length esters (isoamyl acetate, ethyl butanoate and ethyl hexanoate) (than for attributes elicited by larger esters (ethyl decanoate).

Identification of volatile compounds, quantification of glycerol and trace elements in distilled spirits produced in Mozambique.

Distilled spirits, in addition to satisfying the legal requirements with respect to its composition, must possess a sensorial quality capable of satisfying its consumers. The present work describes the analysis of volatile compounds, trace elements and glycerol in thirteen samples of Mozambican spirits collected in different regions of the country. Extraction of volatile components was a accomplished using the headspace SPME technique, the quantification of glycerol was achieved by UV/Vis spectroscopy and the determination of trace elements by atomic absorption spectrometry. Of the 35 volatile compounds identified, 19 were esters, of which ethyl hexanoate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, ethyl laurate, ethyl hexadecanoate, ethyl tetradecanoate, ethyl benzenepropanoate, 3-methylbutyl acetate and isoamyl alcohol were the predominant compounds found in the different samples, contributing to the characteristics and aroma of the beverages. As for glycerol, concentrations below 5mgL-1 were observed in all the samples studied. The samples were found to be contaminated by metals such as copper, lead and zinc. In addition, the results provided information on the quality of Mozambican spirits regarding some aspects related to the determination of metals and glycerol. This information might stimulate producers to be more attentive to the conditions of production and the risks involved in achieving good quality spirits.

Effects of Ethanol Concentration on Oral Aroma Release After Wine Consumption.

This paper evaluates, for the first time, the effects of ethanol concentration on the dynamics of oral (immediate and prolonged) aroma release after wine consumption. To do this, the intraoral aroma release of 10 panelists was monitored at two sampling points (0 and 4 min) after they rinsed their mouths with three rosé wines with different ethanol content (0.5% v/v, 5% v/v and 10% v/v) that were aromatized with six fruity esters (ethyl butanoate, isoamyl acetate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate and ethyl decanoate). Overall, the results indicated that the extent of the effects of ethanol content on the oral aroma release were influenced by the subject, the ethanolconcentration and the type of aroma compound. This effect was also different in the immediate than in the prolonged aroma release. In the first in-mouth aroma monitoring, an increase in the ethanol content provoked a higher release of the more polar and volatile esters (ethyl butanoate, ethyl pentanoate), but a lower release for the more apolar and less volatile esters (ethyl octanoate, ethyl decanoate). Regarding the prolonged oral aroma release, an increase of ethanol content in wine increased the oral aroma release of the six esters, which might also increase the fruity aroma persistence in the wines. Future works with a higher number of individuals will be needed to understand the mechanisms behind this phenomenon.

Modelling Changes in Volatile Compounds in British Columbian Varietal Wines That Were Bottle Aged for Up to 120 Months

This research quantified 46 volatile compounds in vintage wines (1998–2005) from British Columbia (BC), which had been bottle-aged for up to 120 months. Wines were analyzed up to five times, between December 2003 and October 2008. Compounds were identified using gas chromatography mass spectrometry (GC-MS) and their concentrations were related to “wine age” using single linear regression (SLR). SLR models were developed for each wine compound (eight alcohol, 12 ester/acetate, one acid, one aldehyde, one sulfur) in eight varietal wines: six red (Cabernet franc, Cabernet Sauvignon, Meritage, Merlot, Pinot noir, Syrah) and two white (Chardonnay, Pinot gris). Parameter estimates (b0, intercept; b1, slope) and R2 values for models were reported for each compound and each variety. Most of the significant SLR models (109/123) had negative slopes (−b1 coefficients), indicating a decrease in the compounds’ concentration with “wine age”. The b1 coefficients were very small for isobutyl acetate, ethyl isovalerate and ethyl decanoate (−0.00013 to −0.0006 mg/L/mon) and largest (most negative) for 3-methyl-1-butanol, ethyl lactate and isobutyl alcohol (−2.26 to −6.26 mg/L/mon). A few SLR models (14/123) had positive slopes (+b1 coefficients), indicating an increase in the compounds’ concentration with “wine age”, particularly for acetaldehyde, diethyl succinate, ethyl formate and dimethyl sulfide. The +b1 coefficients were smallest for ethyl decanoate (0.0001 mg/L/mon) and dimethyl sulfide (0.00024 mg/L/mon) and largest for dimethyl succinate and acetaldehyde (0.06 mg/L/mon). These values varied by four orders of magnitude (104), reflecting the large concentration range observed for the different volatile compounds. The work provided, for the first time, an empirical (non-theoretical) approach to documenting the evolution of volatile compounds in BC wines. It equipped the industry with an easy-to-use new tool for predicting the concentration of desirable or undesirable compounds in their wines and assisted the industry with decision making regarding the release of their wines into the marketplace.

Experimental investigation and modeling of thermophysical properties of ethyl decanoate at high temperatures

The use of ethyl decanoate combined with conventional diesel or biodiesel could be economically attractive. Thermophysical properties of ethyl decanoate at high temperatures can be an essential guidance for the structural design and optimization of the fuel injection system in diesel engine. The measurements of the speed of sound and the thermal diffusivity of ethyl decanoate (EeC10: 0) were carried out by the light scattering method, which are along five isobaric lines from (0.1–10) MPa at the temperatures (300.71–562.07) K and (295.34–565.49) K, respectively. The expanded relative uncertainties (k = 2) of the measurement systems are estimated to be 1.2% for speed of sound and 2.4% for thermal diffusivity. The thermal conductivities of ethyl decanoate at pressures up to 10 MPa and in the temperature range (303–363) K are derived, which agree well with literature values finding an AAD of 0.81%. The pρT dependences of the thermal conductivity are analyzed based on the vibrational theory. The results obtained show that the higher density of biofuels leads to smaller distances between oscillating molecules, of which the collision probability and intermolecular energy transport are enhanced. The consistent behaviors of biofuels that higher density leads to higher conductivity, and the dependence of the thermal conductivity on density becomes smaller with temperature increase are verified.

Effects of Saccharomyces cerevisiae in association with Torulaspora delbrueckii on the aroma and amino acids in longan wines.

This study investigated the effects of monocultures of Saccharomyces cerevisiae and Torulaspora delbrueckii as well as simultaneous and sequential cultures of S. cerevisiae and T. delbrueckii on the nonvolatile and volatile compounds in longan wines. The four cultures had similar characteristics in longan wines. The main amino acids in all the fermentations were glutamic acid, arginine, alanine, leucine, proline, and GABA. The main volatile compounds in longan wines were ethanol, isoamyl alcohol, isobutanol, 2‐phenylethanol, isoamyl acetate, ethyl decanoate, ethyl octanoate, ethyl hexanoate, and ethyl acetate, which can contribute more desired aroma compounds in wines. Among the four treatments, the longan wine fermented with the simultaneous culture produced the highest total volatile aroma content (345.26 mg/L). The simultaneous culture also had a better ability to generate a high level of the main volatile compounds in longan wines and also could achieve a noticeable intensity of floral and fruity aromas of wine as evaluated by calculation of the odor activity values.

The Influence of Selected Autochthonous Saccharomyces cerevisiae Strains on the Physicochemical and Sensory Properties of Narince Wines

Vitis vinifera cv. Narince is a Turkish native white grape variety. In this study, volatile and sensory properties of Narince wines that are produced with autochthonous Saccharomyces cerevisiae (S. cerevisiae) strains and commercial strain were compared. Autochthonous yeast strains 1044 (MG017575), 1088 (MG017577), and 1281 (MG017581) were previously isolated from spontaneous fermentations of Narince grapes. Volatile compounds formed in wines were extracted using a liquid–liquid extraction method and determined by GC-MS-FID. All yeast strains fermented Narince grape juice to dryness. The differences between the volatile profiles of the yeast strains were determined. Wines fermented with autochthonous strains 1281 and 1044 produced a higher amount of acetates and ethyl esters. While the highest concentrations of ethyl hexanoate and hexyl acetate were found in wine fermented with 1044, the highest concentrations of ethyl octanoate, ethyl decanoate, isoamyl acetate, and 2-phenylethyl acetate were found in wine fermented with strain 1281. Also, the highest contents of 2-phenyl ethanol and linalool were found in wine fermented with strain 1281. According to sensory analysis, the wine fermented with 1281 achieved the best scores in floral and fruity attributes, as well as balance and global impression. The data obtained in the present study showed that autochthonous yeast strains affect the final physicochemical composition and sensory profile of Narince wines.

Indigenous Yeast Interactions in Dual-Starter Fermentations May Improve the Varietal Expression of Moschofilero Wine.

Multi-starter wine fermentations employing non-Saccharomyces (NS) yeasts are becoming an emerging trend in winemaking. It is therefore important to determine the impacts of different NS strains in the wine phenotype and in particular the aroma outputs in different inoculation schemes and fermentation conditions. Here, two native NS yeasts, Lachancea thermotolerans LtMM7 and Hanseniaspora uvarum HuMM19, were assessed for their ability to improve the quality of Moschofilero, a Greek aromatic white wine. The NS strains were initially examined in laboratory scale fermentations in mixed inoculations with ScMM23, a native Saccharomyces cerevisiae strain. LtMM7 was selected to be further evaluated in pilot scale fermentations. Five different inoculation schemes were considered: single inoculation of ScMM23 (IS), simultaneous inoculation of ScMM23 with HuMM19 (SMH) or LtMM7 (SML), and sequential inoculation of HuMM19 (SQH) or LtMM7 (SQL) followed by ScMM23. At laboratory scale fermentations, the chemical profiles were largely affected by both the NS species and the inoculation scheme applied. The sequential inoculation using HuMM19 produced the most divergent wine phenotype. However, HuMM19 caused significant increases in acetic acid and ethyl acetate levels that impeded its use in pilot scale trials. LtMM7 significantly affected the chemical profiles of wines produced at the winery, especially in the sequential inoculation scheme. Importantly, LtMM7 significantly increased the levels of acetate esters or ethyl esters, depending on the inoculation method applied. In particular, acetate esters like isobutyl acetate, hexyl acetate, and 2-phenylethyl acetate, which all impart fruity or floral aromas, were significantly increased in SQL. On the other hand, higher levels of total ethyl esters were associated with SML. The most striking differences were observed in the levels of fruit-impair esters like ethyl decanoate, 3-methylbutyl octanoate, and isoamyl hexanoate. This is the first study to report a significant increase in the ethyl ester fraction by L. thermotolerans. Interestingly, L. thermotolerans in SQL also increased the concentrations of damascenone and geraniol, the major teprenic compound of Moschofilero, which are associated with several typical floral and fruity aromas of the variety. Present results show that L. thermotolerans may enhance the varietal character and increase the chemical complexity of Moschofilero wines.

Attraction of the Invasive Hornet, Vespa velutina nigrithorax, by using Bacillus sp. BV&amp;#8208;1 Cultures

BACKGROUND: The invasive hornet Vespa velutina nigrithorax has becomes a public concern in rural and urban South Korea. The technologies are necessary to develop a way to counter V. velutina. In an effort to develop a way to counter V. velutina, we found that a bacillus strain, named Bacillus sp. BV-1, produces volatile compounds that attract V. velutina. METHODS AND RESULTS: Field trials of V. velutina attraction were performed using plates and traps containing BV-1 cultures grown on sugar medium. When the sugar medium and sugar-grown BV-1 cultures in the plates were placed close together, V. velutina visited preferably the plates with the BV-1 cultures. Significantly more V. velutina were caught in the traps containing BV-1 cultures than in those containing only sugar medium. Headspace solid-phase microextraction coupled with GC/MS analysis of BV-1 cultures detected 2-methyl-1-propanol, 3-methyl-1-butanol, 3-methylbutanoic acid, ethyl hexanoate, 2-pheylethanol, ethyl octanoate, and ethyl decanoate as the major volatiles. CONCLUSION: BV-1 cultures were suggested as potential agents for managing V. velutina as they produce volatile compounds that attract the hornet.

Flavour component analysis by HS-SPME/GC–MS and chemometric modeling to characterize Pilsner-style Lager craft beers

An HS-SPME/GC–MS (Head Space-Solid Phase Micro Extraction/Gas Chromatography-Mass Spectrometry) method was developed and applied to 79 beers (craft and industrial products) selected among the most common brands of mass-produced beer to evaluate their flavour profile. 111 volatiles were identified in the samples. PLS-DA (Partial Least Squares-Discriminant Analysis) was used to classify beers according to their different production methods. Good classification results both in calibration and cross-validation were obtained enabling a good separation between beer categories with high prediction accuracy. In order to find a reduced number of volatiles which could be relevant to discriminate the two beer typologies, VIP (Variable Importance in Projection) scores were calculated; on the basis of these results it was possible to identify a panel of 13 substances contributing the most to the observed differentiation (2-Methylpropyl 2-methylpropanoate, 3-Methylbutyl acetate, 7-Methyl-3-methylideneocta-1,6-diene (β-Myrcene), 3-Methylbutan-1-ol, Ethyl hexanoate, Hexan-1-ol, 1,1-Dimethyl-4-methylenehexahydro-1H-cyclopenta[c]furan, Ethyl octanoate, 3,7-Dimethylocta-1,6-dien-3-ol (β-Linalool), Ethyl decanoate, 2-Phenylethyl acetate, 2-Phenylethanol, Octanoic acid). The aim was to characterize the craft beers to differentiate them from other competing and lower quality products. The proposed approach could be a useful tool to verify whether samples comply with the statements reported on label concerning production process set out by product specification, at the same time providing a more chemically-oriented definition of the peculiar characteristics of craft beers.