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BACKGROUND Strong-flavor baijiu is a traditional distilled alcoholic beverage with a long history in China. The fermented grains play a pivotal role in the production of baijiu. The purpose of this study was to evaluate and compare the microbiota and flavor substances present in fermented zaopei (ZP) from pits of different ages. High-throughput sequencing, headspace solid-phase microextraction gas chromatography-mass spectrometry, principal component analysis, community composition analysis, and redundancy analysis were used to analyze and evaluate the impact of environmental factors on microbial communities and flavor substances. RESULTS Six genera of bacteria (e.g., Caproiciproducens, Syntrophaceticus, Sedimentibacter, Hydrogenispora, Pelotomaculum and Bacillus) and seven genera of fungi (Cladosporium, Debaryomyces, Dipodascus, Auxarthron, Cephalotrichum, unclassified Stachybotryaceae, unclassified Microascaceae and Cephalotrichum) notably affected the production of hexanoic acid (an important flavor compound). Moisture and alcohol content also had considerable effects on the production of the flavor compounds such as ethyl lactate, hexanoic acid, and ethyl hexanoate. The profiles of volatile compounds present in ZP were different between the aged and new pits; these profiles were mainly reflected in the concentration and types of alcohols, aldehydes, esters, and aromatic compounds. CONCLUSIONS This paper provides a comprehensive overview of the physicochemical parameters, flavor substances, and microbial population distribution of ZP. Characterization of various ZP samples help to elucidate the fermentation mechanisms and offer a theoretical reference to control and enhance the quality of Baijiu. © 2021 Society of Chemical Industry.

Petit Manseng (Vitis vinifera L.) has become a popular variety in China for the production of semisweet and sweet wines. However, few studies focused on investigating the molecular odor code of its key odorants. In this study, the key odor-active compounds of Chinese sweet Petit Manseng wine were identified by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Fifty-five odorous zones were sniffed and identified by application of aroma extraction dilution analysis on a distillate prepared by liquid-liquid extraction and solvent-assisted flavor evaporation. Among them, isoamyl alcohol, ethyl octanoate, isovaleric acid, (E)-β-damascenone, and phenylethanol particularly displayed with highest flavor dilution factors above 1024. The quantification of volatiles by headspace solid-phase microextraction coupled with GC-MS and GC coupled with triple quadrupole MS/MS and a calculation of odor activity values (OAVs) indicated 23 volatiles with OAVs above 1. Ethyl hexanoate showed the highest OAV with 208.8, followed by (E)-β-damascenone (189.0), 3-mercaptohexanol (60.3), isoamyl acetate (45.4), and furaneol (40.1). The aroma of the sweet wine was successfully reconstituted by combining 42 aroma compounds in a model wine solution. 3-Mercaptohexanol, (E)-β-damascenone, furaneol, γ-octalactone + γ-decalactone + γ-hexalactone, and ethyl cinnamate had important influence on the aroma of sweet Petit Manseng wine assessed by omission tests. Moreover, the discrimination of wines from three regions was successfully achieved by partial least squares discriminant analysis based on quantitative results of key odorants. 3-Mercaptohexanol was considered as the most responsible for the region discrimination and had highest concentrations in Petit Manseng wines from Jiaodong Peninsula. PRACTICAL APPLICATION: Understanding of the knowledge in key odorants of Petit Manseng wines could be useful to improve wine quality through viticultural and enological practices.

Background Icewine produced in China is becoming popular, but there is only limited knowledge available on the yeast population that occurs during fermentation and also on the selection of indigenous Saccharomyces cerevisiae strains for its production. In this work, we first investigated yeast species and the evolution of yeast population in spontaneous fermentations of icewine produced in the Qilian region of China and then analyzed the biodiversity and important enological properties of S. cerevisiae isolates. Results Seven species of five genera including S. cerevisiae, S. uvarum, Torulaspora delbrueckii, Hanseniaspora uvarum, Lachancea thermotolerans, Metschnikowia aff. fructicola and H. osmophila were identified by the colony morphology on Wallerstein Laboratory Nutrient medium and sequence analysis of the 26S rRNA gene D1/D2 domain. Saccharomyces cerevisiae, H. uvarum and L. thermotolerans were the dominant species, representing almost 87% of the total yeast isolates. Microvinification with seven preselected S. cerevisiae strains were performed on Vidal. All selected strains could complete fermentations, and the enochemical parameters were within the acceptable ranges of the wine industry. W5B3 produced higher amounts of ethyl hexanoate and ethyl octanoate than other strains. R3A10 was a low volatile acid producer and the corresponding icewine presented the highest values on some odorants including β-damascenone, 1-octen-3-ol, ethyl 2-methylbutyrate, and isoamyl alcohol. Vidal icewines fermented with R3A10, R3A16 and W5B3 were well accepted by the judges because of superior sensory quality. Conclusion Three indigenous strains (R3A10, R3A16 and W5B3) could be used as starters and could potentially improve the regional character of the icewine in Qilian. © 2020 Society of Chemical Industry.

Changes in the oenological parameters, total phenols, total flavonoids, and individual phenols of persimmon during spontaneous and inoculated fermentation were investigated. The volatile compounds and sensory character of the persimmon wine were compared and evaluated simultaneously. Results show that at the end of fermentation, spontaneous persimmon wine (SPW) has higher contents of total flavonoids, total phenols yet lower concentrations of alcohol and volatile compounds than inoculated persimmon wine (IPW). Catechin, salicylic acid, quercetin, and vanillic acid were the main phenolic compounds in both types of persimmon wine. There are six volatile components in the IPW with an OAV greater than 1, which are isoamyl acetate, ethyl hexanoate, methyl octanoate, ethyl octanoate, phenethyl acetate, and 2, 4‐di‐tert‐butylphenol, and these compounds contribute to the IPW with brandy and fruity sensory properties, while only three volatile components in SPW have OAV greater than 1, which are isoamyl acetate, ethyl hexanoate, and ethyl octanoate. Spontaneous fermentation increased the proportion of esters and alcohols in the overall volatile compounds. During sensory evaluation, IPW was characterized by “brandy,” “bitterness,” and low “sweetness,” and SPW has a high score of “sweetness,” “balance,” desirable “color,” and “body.”, Changes in the oenological parameters, total phenols, total flavonoids, and individual phenolic compounds of persimmon wine during spontaneous and inoculated fermentation were investigated. The volatile compounds and sensory character of the persimmon wines were compared and evaluated simultaneously.

Carob liqueur is an alcoholic drink (minimum 15% v/v of ethanol and 100 g/L of sugar) typical for the Mediterranean countries. In the current work, carob macerate produced by maceration of carob pods in hydroalcoholic base at different maceration conditions was characterized for the first time based on its aroma compounds/profile, physicochemical parameters, and chromatic characteristics. The results confirm the migration process of bioactive compounds, aroma compounds, and sugars flowing from the carob pod to the hydroalcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, color, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs, and sugars (mostly sucrose) ranging between 96 and 107 g/L. Twenty‐six (out of total 94) aroma compounds were detected in all samples, of which 17 esters, 3 alcohols, 4 ketones, and 2 acids. Low molecular weight ethyl esters, ethyl hexanoate, ethyl 2‐methyl propanoate, ethyl octanoate, ethyl benzoate, ethyl butanoate, and ethyl cinnamate, were the most abundant. Carob pod maceration in 50% v/v hydroalcoholic base (1:5 solid to liquid ratio) in darkness at room temperature during 8 weeks can be recommended as optimal maceration conditions for production of the aromatic carob macerate with functional properties., The results confirm migration process such as: bioactive compounds, aroma compounds, and sugars flows from the carob pod to the alcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, colour, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs.

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.

BACKGROUND Chinese rice wine (CRW) is a kind of traditional fermentation wine in China. Aged CRW is more popular among consumers owing to its harmonious and pleasant flavor. The volatile profile of CRW has been extensively studied using gas chromatography/mass spectrometry (GC/MS). However, flavor components in CRW are far richer than those detected by GC/MS. To obtain more information about the volatile profile of fresh (5-year) and aged (10-year) CRW, a method based on comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC×GC/qMS) was developed. The major volatile compounds contributing to the characteristic aroma of fresh and aged CRW were identified by surrogate odor activity value (OAV). RESULTS Ninety-eight volatile compounds were detected in the 5-year CRW samples and 107 in the 10-year samples by GC×GC/qMS. The numbers of compounds detected by GC×GC/qMS for the 5-year and 10-year samples were 71.4 and 65.4% higher than those detected by GC/MS. The aged wine had a more complex volatile profile than the fresh wine, with an increase in esters and aldehydes and a decrease in alcohols and organic acids. There were 22 volatile compounds with surrogate OAV > 1. Nine were the potent key aroma compounds in CRW: ethyl isovalerate (OAV 500-33 500), ethyl butyrate (OAV 84-334), ethyl isobutyrate (OAV 49-170), 2-nonenal (OAV 20-100), ethyl heptanoate (OAV 1-74), ethyl hexanoate (OAV 60-77), phenylethyl alcohol (OAV 2-18), benzaldehyde (OAV 28-30) and hexanal (OAV 4-11). CONCLUSION GC×GC/qMS showed better separation than GC/MS. The presented GC×GC/qMS method was suitable for characterization of the volatile profile of CRW. © 2019 Society of Chemical Industry.

In cooperative catalysis, the combination of chemo- and biocatalysts to perform one-pot reactions is a powerful tool for the improvement of chemical synthesis. Herein, UiO-66-NH2 was employed to stepwise immobilize Pd nanoparticles (NPs) and Candida antarctica lipase B (CalB) for the fabrication of biohybrid catalysts for cascade reactions. Distinct from traditional materials, UiO-66-NH2 has a robust but tunable structure that can be utilized with a ligand exchange approach to adjust its hydrophobicity, resulting in excellent catalyst dispersity in diverse reaction media. These attractive properties contribute to the formation of MOF-based biohybrid catalysts with high activity and selectivity in the synthesis of benzyl hexanoate from benzaldehyde and ethyl hexanoate. With this proof-of-concept, we reasonably expect that future tailor-made MOFs can combine other catalysts, ranging from chemical to biological catalysts for applications in industry.

The aim of this study was to investigate the role of saliva esterase activity on carboxylic esters typically associated with pleasant and fruity aromas in wine. For this, ex vivo experiments using the same fresh and inactivated (without enzymatic activity) human saliva with a mixture of carboxylic esters with different aliphatic chain length (ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, and isoamyl acetate) were prepared. Liquid-liquid extraction with dichloromethane and GC-MS analysis were applied to the saliva systems in order to determine the reduction in ester content and the formation of their corresponding metabolic products (carboxylic acids) in the saliva systems before and after incubation at 37C. In addition, to check if there was a relationship between the susceptibility of esters to saliva hydrolysis and the amount of in-mouth ester release during wine intake, the remaining oral amount of each ester was determined by comparing the intraoral amount immediately after spitting out the wine and 4 min later. Ex vivo experiments showed ester degradation by saliva esterase enzymes mainly acted on long chain esters (ethyl octanoate and ethyl decanoate), which gave rise to the formation of their corresponding carboxylic acids. Nonetheless, in spite of their higher susceptibility to saliva enzymes, in vivo experiments showed that long chain carboxylic esters remained in the oral cavity long after swallowing. This confirmed that ester hydrophobicity is closely related to the in-mouth temporal release of these odorants and, therefore, behind wine aroma persistence. In wines, esters represent a group of aromatic compounds of great interest since they are linked to pleasant fruity aroma nuances. Today wine consumers are demanding fresh and long persistent fruity aromatic wines. The present research contributes to better understanding the relationship between ester content in the wine and oral aroma release experienced during wine tasting, considering the changes in these compounds during oral processing. This is a necessary step when trying to unravel the factors involved in wine aroma perception and in consumer preferences, and it represents a necessary knowledge in promoting winemaking practices (e.g., the use of selected microorganisms) for improving the type and amount of these aroma compounds in the wine., Spanish Ministry of Economy and Competitiveness (MINECO), Grant/Award Number: Project AGL2016‐78936‐R

Carignan noir is one of the minor and ancient varieties from the Chilean wine scenario that has had a resurgence as a result of to its rediscovered oenological potential when cultivated under the conditions of the interior dryland area. Under these growing conditions Carignan noir wines stand out as fruit driven and fresh compared to those originating from other growing areas. On the other hand, it is well known that wine aroma composition depends mainly on variety, viticultural management and winemaking. Thus, the present study aimed to investigate the volatile composition of wines from Carignan noir grapes originating from ungrafted and grafted onto Pais grapevines, in ten sites of the Maule Valley (Chile) during two consecutive vintages.; Results: Higher alcohols were the most abundant volatile compounds, whereas ethyl esters and s-damascenone were the most odoriferous compounds according to their odorant activity value. The dominant factor in Carignan noir wine volatile composition was season, whereas rootstock did not have a significant effect in differentiating the wines. In terms of climate, cold nights during the month prior to harvest correlated with higher linalool, α-terpineol and trans-3-hexen-1-ol content. The biologically effective degree-days index was inversely correlated with isoamyl acetate and 2-phenylethyl acetate content. Huglin's heliothermal and the average mean temperature of the warmest month indices were inversely correlated with ethyl vanillate, ethyl hexanoate and ethyl octanoate content.; Conclusion: Site climate conditions were related to the accumulation of certain wine volatile compounds. This information may be useful for devising new Carignan noir vineyard management strategies when aiming to improve wine quality or adjust site selection approaches to maximize grape/wine volatile composition according to wine style. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

Mandragora autumnalis Bertol. (Solanaceae family), synonym of M. officinalis Mill., occurs in North Africa and grows natively in Northern and Central Tunisia, in humid to sub-arid climates. The ripe fruits of mandrake are odiferous with a particular, indescribable, specific odor, shared, to a lesser extent, by the leaves and roots. We carried out an investigation of the essential oils (EOs) and of the aromatic volatiles emitted by fresh leaves, roots and ripe fruits of M. autumnalis growing wild in Central Tunisia. The EOs were obtained from freshly collected plant material by hydrodistillation, while the volatile emissions from the powdered M. autumnalis tissues were sampled by headspace solid phase microextraction (HS-SPME); both types of samples were analyzed by gas chromatography-mass spectrometry (GC/MS). Fifty-one compounds representing 96.2-98.6 % of the total oil compositions were identified in the three tissues and belonged to different chemical classes specifically in 16 esters, 12 alcohols, 12 hydrocarbons, 6 ketones, 3 aldehydes and 3 acids. The main constituents were pentadecanoic acid (34.2 %) and hexadecanol (26.3 %). A total of 78 volatile compounds emanating from M. autumnalis tissues, representing 94.1-96.4 % of the total volatile compositions, were identified: 22 esters, 11 alcohols, 9 aldehydes, 14 ketones, 7 nitrogen, 10 hydrocarbons, 2 lactones, 1 sulfur and 2 ethers. Ethyl hexanoate (12.3 %) and 1,3-butanediol (12.3 %) were at the highest relative percentages. This study characterizes and distinguishes M. autumnalis from Tunisia and attributes the compounds responsible for the intoxicating and particular odor of fruits. Chemosystematic of Mandragora autumnalis based on the identification of essential oils and headspace volatiles of each of its organ can be used to characterize this species according to its geographic distribution.

The sexual and host-related behaviours of the fruit fly Anastrepha obliqua Macquart (Diptera: Tephritidae) are mediated by volatile compounds. However, whether the physiological state of this species affects its antennal and behavioural responses to semiochemicals is unknown. The effects of age, mating status, diet and the topical application of methoprene, a Juvenile hormone analogue (JHA), on the antennal sensitivity of this tephritid fruit fly species to selected male [(Z)-3-nonenol] and host fruit volatiles (ethyl benzoate, ethyl hexanoate, ethyl butyrate and trans-β-ocimene) are investigated using electroantennography (EAG). Overall, (Z)-3-nonenol and ethyl benzoate elicit the highest EAG responses in both sexes. Flies of both sexes aged 1, 5 and 10 days old show higher EAG responses to the tested compounds compared with flies aged 20 days old. Virgin females and males show higher EAG responses to volatile compounds than mated flies. Females and males fed with sugar plus protein show higher antennal responses to volatiles compared with flies fed sugar or protein alone. Flies of both sexes treated with methoprene show higher antennal responses than flies treated with acetone (control). These results suggest that the peripheral olfactory system in A. obliqua is modulated by the physiological state of the flies.

The influence of fermentation temperatures (8, 16, and 32°C) and yeast levels (2, 4, and 6%) on the formation of volatile compounds in the crumb of whole-meal wheat bread was investigated. Volatile compounds were extracted by dynamic headspace extraction and analyzed by gas chromatography–mass spectrometry. Results were evaluated with multivariate data analysis and ANOVA. Bread fermented at a high temperature (32°C) had higher peak areas of the Maillard reaction products 2-furancarboxaldehyde, 2-acetylfuran, 2-methylpyrazine, and phenylacetaldehyde compared with bread fermented at lower fermentation temperatures. Bread fermented at low temperatures (8 and 16°C) was characterized by having higher peak areas of the fermentation products 3-methylbutanal, 2-methylbutanal, ethyl acetate, ethyl hexanoate, ethyl propanoate, and 3-methylbutanol. Fermentation of bread with 6% yeast resulted in a higher peak area of the important fermentation product 2-phenylethanol. It also reduced the peak areas of important lipi...

The aroma profile of different aroma-types of Chinese liquors was measured using gas chromatography–mass spectrometry (GC-MS) and sensory evaluation. Sensory analysis coupled with principal component analysis (PCA) showed that strong-aroma liquors were mainly characterized by cellar aroma; light-aroma liquors were mainly characterized by fen, floral, grain, sweet and vinegar aromas while sauce-aroma liquors were mainly characterized by sauce, fruity and caramel aromas. Partial least squares regression (PLSR) results indicated that ethyl hexanoate, hexanoic acid, hexyl hexanoate, 4-methyl pheno, ethyl pentanoate, isoamyl hexanoate and pentanoic acid were significantly and positively associated with cellar aroma and strong-aroma liquors. Vinegar and fen aroma were strongly linked with light-aroma liquor and associated with of ethyl acetate, 2-methylpropyl acetate, isoamyl acetate, isoamyl lactate, ethyl decanoate, diethyl butanedioate, 2-phenethyl acetate, 3,4-dihydro-2H-1-benzopyran-2-one 1-dodecanol, ethyl decanoate, 3-methyl-1-butanol and thymol. While sauce-aroma liquors were positively correlated with caramel, fruity and sauce sensory descriptors and volatile compounds such as ethyl 2-methylpropanoate, ethyl 3-methylbutanoate, furfural, 1,3-dimethyl trisulfide, trimethyl pyrazine, ethyl benzeneacetate, benzaldehyde and 1-octanol. Copyright © 2016 John Wiley & Sons, Ltd.

The volatile compounds originating from fresh clove (Syzygium aromaticum) buds cultivated in a medicinal plant garden located in southern Tokyo were investigated. The volatile compounds originating from fresh clove buds were adsorbed onto polydimethylsiloxane-coated devices and then analysed using gas chromatography-mass spectrometry. Sampling was performed at three different development stages of clove buds, i.e., phase I (green), phase II (pink), and phase III (red). In thermal desorption-gas chromatography-mass spectrometry procedure volatile compounds: eugenol, β-caryophyllene, α-humulene, α-farnesene, and eugenol acetate were the predominant constituents in most cases. Methyl salicylate, α-copaene, β-ocimene, 2-nonanone, ethyl hexanoate, and acetophenone were additionally found as the buds ripened. Volatile compounds obtained from clove leaves were analysed using the same method, and β-caryophyllene, eugenol, α-humulene, 3-hexen-1-ol, 3-hexen-1-yl acetate, and hexyl acetate were identified. The antioxidant activity of both water and methanol extracts of clove buds and leaves collected from the medicinal plant garden was confirmed using electron spin resonance spectrometry. Scavenging activities against superoxide anion radical and hydroxyl radical were evaluated. Copyright © 2015 John Wiley & Sons, Ltd.

Headspace solid-phase microextraction was used for isolation of the volatile compounds from gabiroba fruit (Campomanesia xanthocarpa O. Berg) and further quantification by gas chromatography–flame ionization detector and identification by gas chromatography/mass spectrometry and gas chromatography–olfactometry (GC-O). The odor-active compounds were evaluated using the Osme technique. Seventy-nine compounds were identified, from which 39 presented odor activity detected by the judges in GC-O analysis. The major compounds were (E)-2-hexenal, ethanol, ethyl hexanoate, hexanal, ethyl butanoate, hexanoic acid, 1-hexanol, (E)-2-hexen-1-ol, linalool, 1-butanol, methyl acetate and α-terpineol, but the substances 4-hydroxy-2,5-dimethyl-2(3H)-furanone, 1-penten-3-ol, an unidentified compound, hexanal, (E,E)-2,4-hexadienal, (Z)-3-hexen-1-ol, ethyl hexanoate, γ-eudesmol, linalool and β-eudesmol were related to the aroma of this fruit. The green and sweet notes were perceived in high frequency of description and intensity, and they were considered important for the characteristic gabiroba aroma. Practical Applications Gabiroba is a native fruit from South America with an intense and pleasant flavor, but there is a few information regarding to its chemical profile of volatile compounds. In this work, the compounds that better represent the gabiroba aroma (odor-active substances) were determined by olfactometric analysis. This information was crucial for sensory characterization of fruit and could be used as a tool for evaluation of processing and postharvest quality.

UNLABELLED The aim of this study was to investigate the dynamic of volatile compounds in the Zaopei during the fermentation and distillation process by headspace solid-phase microextraction-gas chromatography mass spectrometry (HS-SPME-GCMS). Physicochemical properties analysis of Zaopei (fermented grains [FG], fermented grains mixed with sorghum [FGS], streamed grains [SG], and streamed grains mixed with Daqu [SGD]) showed distinct changes. A total number of 66 volatile compounds in the Zaopei were identified, in which butanoic acid, hexanoic acid, ethyl hexanoate, ethyl lactate, ethyl octanoate, hexyl hexanoate, ethyl hydrocinnamate, ethyl oleate, ethyl hexadecanoate, and ethyl linoleate were considered to be the dominant compounds due to their high concentrations. FG had the highest volatile compounds (112.43 mg/kg), which significantly decreased by 17.05% in the FGS, 67.12% in the SG, and 73.75% in the SGD. Furthermore, about 61.49% of volatile compounds of FGS were evaporated into raw liquor, whereas head, heart, and tail liquor accounted for 29.84%, 39.49%, and 30.67%, respectively. Each volatile class generally presented a decreasing trend, except for furans. Especially, the percentage of esters was 55.51% to 67.41% in the Zaopei, and reached 92.60% to 97.67% in the raw liquor. Principal component analysis based ordination of volatile compounds data segregated FGS and SGD samples. In addition, radar diagrams of the odor activity values suggested that intense flavor of fruit was weakened most from FG to SGD. PRACTICAL APPLICATION The dynamic of volatile compounds in the Zaopei during the fermentation and distillation process was tested by SPME-GCMS. The result of this study demonstrated that both volatile compounds of Zaopei and thermal reaction during distillation simply determined the unique feature of raw liquor. This study was conducted based on the real products from liquor manufactory, so it is practicable that the method can be used in an industry setting.

An atmospheric pressure chemical ionization ion-trap mass spectrometer was set up for the on-line analysis of aroma compounds. This instrument, which has been successfully employed for some years in several in vitro and in vivo flavour release studies, is described for the first time in detail. The ion source was fashioned from polyether ether ketone and operated at ambient pressure and temperature making use of a discharge corona pin facing coaxially the capillary ion entrance of the ion-trap mass spectrometer. Linear dynamic ranges (LDR), limits of detection (LOD) and other analytical characteristics have been re-evaluated. LDRs and LODs have been found fully compatible with the concentrations of aroma compounds commonly found in foods. Thus, detection limits have been found in the low ppt range for common flavouring aroma compounds (for example 5.3 ppt (0.82 ppbV) for ethyl hexanoate and 4.8 ppt (1.0 ppbV) for 2,5-dimethylpyrazine). This makes the instrument applicable for in vitro and in vivo aroma release investigations. The use of dynamic sensory techniques such as the temporal dominance of sensations (TDS) method conducted simultaneously with in vivo aroma release measurements allowed to get some new insights in the link between flavour release and flavour perception. Copyright © 2014 John Wiley & Sons, Ltd.

The African fig fly, Zaprionus indianus Gupta, is rapidly spreading through the New World and is a new potential pest for numerous fruit crops. Methods are needed to detect and monitor Z. indianus. A recent study shows that Z. indianus can be attracted with a mixture of wine and vinegar, but there are no chemical attractants yet identified. This fly was captured incidentally as a non-target insect in experiments to develop chemical lures, based on wine and vinegar fermentation volatiles, for Drosophila suzukii Matsumura and Drosophila melanogaster Meigen. We then generated testable hypotheses on what combination of these volatiles was involved in Z. indianus attraction to wine and vinegar. We determined through a series of trapping experiments that the blend of ethanol, acetic acid, acetoin, isoamyl acetate, methionol and ethyl hexanoate constitutes a strong attractant for Z. indianus and accounts for its attraction to the combination of wine and vinegar. These results and findings provide the first opportunity to develop a long-lasting and consistent chemical lure for trapping of Z. indianus. Such a lure in a suitable trap should provide a good means to document the spread of the fly and determine its seasonality and abundance in new areas and crops.

Summary The aim of this work was to investigate the effects of high-pressure homogenisation on the aroma retention of mixed sodium caseinate–whey protein (2% + 2% w/v) emulsions. For this purpose, raw and pasteurised emulsions, with different fat contents (5%, 8% and 15% w/v) and subjected to different homogenisation pressures (0, 18, 100 and 150 MPa), were produced. The retention of seven aroma compounds (hexanal, benzaldehyde, diacetyl, ethyl butyrate, isoamyl acetate, ethyl hexanoate and ethyl octanoate) was evaluated by static headspace gas chromatography. Results showed that aroma release was affected by the presence and the quantity of the lipid phase. As regards homogenisation, an increase in the retention of hexanal with homogenisation pressure was observed and interactions between hexanal and caseinate were suggested. Benzaldehyde showed significant changes in headspace partition with increasing pressure only in the 5% fat content emulsions, whereas no homogenisation effect on aroma retention was observed for diacetyl or esters.

The diffusion of aroma volatiles in set-type acidified dairy matrices of different composition and structure was investigated using the concentration profile technique (CPT) in combination with headspace gas chromatography (HSGC). Multiphase confocal laser scanning microscopy and puncture testing were used to characterize the micro- and macrostructure of the matrices. Aroma volatiles under investigation included diacetyl, (Z)-3-hexenol, ethyl butanoate, ethyl-2-methylbutanoate, (Z)-3-hexenyl acetate, ethyl hexanoate and limonene, and covered a wide range of hydrophobicity. CPT in combination with HSGC was found suitable to determine apparent diffusion coefficients at equilibrium. Increased overall protein content decreased the diffusivity of hydrophobic volatiles. At 4% protein content, diffusivity remained unaffected by process-induced changes in the protein network density. Addition of milk fat substantially decreased the mobility of hydrophobic volatiles. In milk fat-containing matrices, the addition of pectin did not change the diffusion properties of the volatiles, independent of their hydrophobicity. Practical Applications This study is relevant to the producers of acidified dairy products such as yoghurt, fresh cheese and quarg. The results specify within which boundaries several core parameters of manufacture, such as the addition of pectin, the intensity of milk heating, shearing and adaptations in protein and fat content, may be changed at a minimized risk of altered aroma delivery during consumption. This information amplifies the technological possibilities of the manufacturers and increases their flexibility in terms of product composition and processing. Aroma suppliers could use the outcomes of this study to modify the composition of their aromas based on dairy product specifications and the hydrophobicity of the individual aroma compounds they are using.

Summary This study evaluated the chemical and volatile composition of lychee wines fermented with four commercial yeast strains of Saccharomyces cerevisiae: EC-1118, R2, 71B and MERIT.ferm. Yeast cell population, pH, malic acid, ammonia and some amino acids had significant differences between strain 71B and other strains. There were strain variations with regard to degradation and retention of some juice volatiles as well as formation of new volatile compounds such as most esters and certain terpene compounds. Ethyl octanoate had the highest odour activity value (OAV of 500–1100), followed by ethyl hexanoate (about 50–85), among the common odorants in all lychee wines. Ethyl octanoate reached its highest OAV (1077) in the lychee wine fermented with strain EC1118, whereas ethyl hexanoate had the highest OAV (85) in the wine fermented with strain MERIT.ferm. Cis-rose oxide, the character-impact volatile in lychee juice with highest OAV (161), was dramatically reduced to trace levels after fermentation.

Background Solid phase microextraction and simultaneous distillation-extraction combined with GC-FID, GC/MS, aroma extract dilution analysis and odour activity values were used to analyse volatile compounds from guava (Psidium guajava L. cv. Red Suprema) and to estimate the most odour-active compounds. Results The analysis led to the detection of 141 compounds, 121 of which were positively identified. The composition of guava fruit volatiles included 43 esters, 37 terpenes, 18 aldehydes, 16 alcohols, ten acids, six ketones, four furans and seven miscellaneous compounds. Conclusion Seventeen odorants were considered as odour-active compounds, with (E)-β-ionone, ethyl hexanoate, ethyl butanoate, hexanal, (Z)-3-hexenal, hexyl acetate, (E)-2-hexenal and limonene contributing most to the typical guava aroma of this cultivar. © 2013 Society of Chemical Industry

Summary Application of solid-phase microextraction, simultaneous distillation–extraction and liquid–liquid extraction combined with GC-FID, GC-MS, aroma extract dilution analysis, and odour activity value was used to analyse volatile compounds from pineapple (Ananas comosus [L.] Merril cv. Red Spanish) and to estimate the most odour-active compounds. The analyses led to the identification of ninety-four compounds, seventy-two of them were positively identified. Twenty odorants were considered as odour-active compounds, from which ethyl 2-methylbutanoate, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, 1-(E,Z,Z)-3,5,8-undecatetraene, ethyl 3-(methylthio)propanoate, 1-(E,Z)-3,5-undecatriene, ethyl hexanoate and methyl hexanoate were the most odour contributors and contribute to the typical pineapple aroma, while the others are responsible for fruity and sweet odour notes.

Summary Changes in the volatile aroma compounds of pineapple (Ananas comosus) during freezing and thawing were compared against fresh samples to determine the effect of freezing on pineapple flavour. An HS-SPME–GC–MS analysis showed that the Smooth Cayenne pineapple variety had nineteen volatile compounds, in four classes of compounds including fourteen esters, two hydrocarbons, two sulphur-containing compounds and one lactone. The main characteristic volatile compounds of the fresh pineapple were methyl hexanoate, ethyl hexanoate, ethyl 3-methylthiopropanoate and 1-(E,Z)-3,5-undecatriene. Freeze–thaw cycles were associated with the loss of some volatile aroma compounds, particularly the esters which were found to be the main characteristic of fresh pineapples. The freezing and thawing process was found to cause damage to the pineapple tissues due to ice recrystallisation and dehydration which lead to the reduction of volatile aroma compounds.

The effect of the pre-harvest treatment with ethanol (EtOH), methyl jasmonate (MJ) and both of them in combination on volatile compounds in strawberry was investigated by applying different concentrations of the hormonal compounds to strawberry plants. In general terms, all treated strawberries exhibited higher total volatile content than untreated control strawberries. Surprisingly, the level of total volatiles dropped significantly by exposing the berries to the highest MJ concentration. This is probably owing to a delay in the strawberry ripening process. The effect of the pre-harvest treatments on specific volatile compounds varied with the chemical structure of the studied compounds. Some of the most important contributors to strawberry aroma (i.e. ethyl butanoate, butyl acetate, hexyl acetate and 2,5-dimethyl-4-hydroxy-2H-furan-3-one) were not significantly affected by MJ/EtOH treatments whereas others (i.e. ethyl hexanoate and methyl hexanoate) were significantly modified. Similarly, some minor compounds, such as styrene, 2-hexenal, 2-heptanone, exhibited insignificant changes with the pre-harvest exposition of strawberry to natural hormonal compounds whilst the levels of linalool, nonanol and nerolidol were significantly distinct between controls and treated samples. No significant variations of the enantiomeric composition of chiral volatile compounds with the treatments were observed, however. The results suggest that the pre-harvest treatment of strawberry plants with natural hormonal compounds is able to slow ripening process by affecting the biochemical pathways implicated in the formation of their components. Copyright © 2012 John Wiley & Sons, Ltd.

Summary The volatile compounds of papaya wine were isolated by continuous solvent extraction and analysed by gas chromatography-flame ionization detector and gas chromatography-mass spectrometry. A total of 118 volatile constituents were detected, and ninety-seven were positively identified. The composition of papaya wine included fifty-three esters, twenty-two alcohols, nine acids, seven phenols and derivatives, seven sulphur compounds, five lactones, five terpenes, three ketones, two aldehydes and five miscellaneous compounds. The aroma-active areas in the gas chromatogram were screened by application of the aroma extract dilution analysis and by odour activity values. Six odorants were considered as odour-active volatiles: ethyl octanoate, (E)-β-damascenone, 3-methylbutyl acetate, benzyl isohtiocyanate; ethyl hexanoate and ethyl butanoate.

A method based on stir bar sorptive extraction combined with gas chromatography-mass spectrometry de-tection (SBSE-GC-MS) has been optimized with the aim of applying it to the analysis of apple pomace. The methodallowed the identification of 124 volatile compounds after 3 h of extraction with a precision (RSDs) ranging between2% (linalool) and 11% (ethyl hexanoate). Its use in analyzing varietal apple pomace revealed the interest of this substrateas regards its content in aromas. From a semi-quantitative point of view, the higher content in aldehydes and estersof the Blanquina variety is worth highlighting, as are the greater concentration of acids in the Clara variety and thehigher content of terpenes and norisoprenoides in the Coloradona variety. In contrast, the Ernestina and Perico varietiespresented the lowest levels of aromas. Keywords: apple, aroma, GC-MS, pomace, SBSE Practical Application: The analysis of varietal apple pomaces showed the importance of this type of waste in the foodindustry, both for its content in aromas such as for its use as substrate in biotechnological processes.

Summary Profiles of volatile organic compound (VOC) produced by nine individual lactic acid bacteria (LAB) during rye sourdough fermentation were compared by automated SPME and GC/MS-Tof. The dough samples were inoculated with individual strains, placed inside the headspace vials and incubated during next 24 h. The production or loss of VOC-s was followed by adsorbing volatiles onto 85-m Car/PDMS fibre in every 4 h. Volatile profiles differed among LAB species and divided LAB into two main groups – hetero- and homofermentative. Hetrofermentative LAB (Lactobacillus brevis; Leuconostoc citreum; Lactobacillus vaginalis, Lactobacillus panis) showed high production of acetic acid, CO2, ethanol, ethylacetate, producing also hexyl acetate, ethyl hexanoate and isopentyl acetate. Whereas homofermentative LAB species (Lactobacillus helveticus; Lactobacillus casei; Lactobacillus sakei; Lactobacillus curvatus) produced a considerable amount of 2,3-butanedione. Production of l-leucine methyl ester was unique for Lb. sakei, Lb. casei and Lb. curvatus strains. Lb. helveticus was the only LAB that produced benzaldehyde.

To investigate the variations of flavor substances in distillation process of Chinese Luzhou-flavor liquor, systematic experiments were carried out in an industrial-scale experimental distiller. Distillate samples were collected continuously throughout the whole distillation process and analyzed by gas chromatography and sensory evaluation. The results show that the compositions and variations of flavor substances mainly depend on their physical and chemical properties. The flavor substances with low boiling point, such as ethanol, acetaldehyde, ethyl format and ethyl acetate, are vaporized quickly and therefore have high contents in the distillate obtained in the early stage of distillation. The flavor substances with high boiling points enter into distillate mainly by extraction and, hence, their variations depend on the dissolving properties. The alcohol-soluble substances, such as ethyl hexanoate, ethyl butanoic and so on, are distilled out mainly in the early stage of distillation, and their extraction rates decrease as the distillation process proceeds, while the water-soluble substances, such as organic acids, ethyl lactate and so on, are mainly present in the latter-stage distillate and the extraction rates increase as the process proceeds. Variations of methanol and furfural were found irregular and the reasons for this irregularity were analyzed. Sensory quality of distillate declines as the distillation process proceeds. PRACTICAL APPLICATIONS Chinese liquor has been a traditional art continuing for thousands of years, but the distillation operation almost holds its way of ancient time and few studies about it have been conducted, so that the understanding of distillation process is largely limited to intuition. Variations of flavor substances during distillation process will certainly contribute to the understanding of distillation mechanism and the optimization of distillation operation. The remarkable differences of distillate qualities found in different distillation stages provide an experimental base for collecting liquors with different distillate qualities. The findings that the high quality distillate is produced in early distillation stage indicate the necessity to overcome the vapor-overflow phenomenon, which occurs usually in the early stage of distillation and causes a lot of loss of high quality liquor. Theoretically, this work will provide the experimental base and testifying data for the modeling of multicomponents mass transfer in liquor distillation process through a packed bed.

BACKGROUND: Partition coefficients give an indication of the retention of aroma compounds by the food matrix. Data in the literature are obtained by various methods, under various conditions and expressed in various units, and it is thus difficult to compare the results. The aim of the present study was first to obtain gas/water and gas/matrix partition coefficients of selected aroma compounds, at different temperatures, in order to calculate thermodynamic parameters and second to compare the retention of these aroma compounds in different food matrices. RESULTS: Yogurts containing lipids and proteins induced a higher retention of aroma compounds than model gel matrices. The observed effects strongly depend on hydrophobicity of aroma compounds showing a retention for ethyl hexanoate and a salting out effect for ethyl acetate. A small but noticeable decrease in enthalpy of affinity is observed for ethyl butyrate and ethyl hexanoate between water and food matrices, suggesting that the energy needed for the volatilization is lower in matrices than in water. CONCLUSION: The composition and complexity of a food matrix influence gas/matrix partition coefficients or aroma compounds in function of their hydrophobicity and to a lower extent enthalpy of vaporization. c � 2010 Society of Chemical Industry

Aroma is one of the most important attributes of orange wine quality. The volatile compounds in orange wine mainly derive from oranges, yeast fermentation and compounds released from odourless glycosidic precursors present in the orange. In this study, free volatile compounds in orange juice and wine made from Citrus sinensis (L). Osbeck cv. Washington Sanguine were analysed by SPME-GC–MS. Bound fractions were isolated and extracted with methanol and Amberlite XAD-2 resin and then hydrolysed by almond β-glucosidase. Totals of 31 and 19 free volatiles were identified in orange juice and wines, respectively. Terpenes were the most abundant compounds in orange juice, while esters were quantitatively the dominant group in orange wine and most of them were compounds newly formed during fermentation, such as isoamyl acetate, ethyl hexanoate, ethyl benzoate, diethyl succinate, ethyl decanoate and ethyl laurate. In total, 11 and three released bound volatiles were found in orange juice and wine, respectively, and most of them were not found in free form. Only ethyl 3-hydroxyhexanoate and cis-carveol were found present in both the free and bound forms of orange juice. Copyright © 2009 John Wiley & Sons, Ltd.

In order to investigate the relationship between sensory and gas chromatographic analysis data, and to establish if particular aroma compounds could be used as Malvazija istarska young wine quality markers, thirty samples of Malvazija istarska young wine were subjected to sensory evaluation and gas chromatographic analysis of aroma compounds. Linear regression and principal component analysis (PCA) were applied in order to establish the relations between sensory evaluation scores and aroma compound concentrations in corresponding wines. The most important contributors to the characterization and differentiation of wines evaluated with higher sensory evaluation scores were isoamyl acetate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, hexanoic acid, octanoic acid and decanoic acid. On the other hand, wines evaluated with lower sensory evaluation scores were characterized and differentiated by higher amounts of isoamyl alcohol and isobutanol. Mentioned esters and acids were also found to be the most important variables for the classification of these wines according to quality using stepwise linear discriminant analysis (SLDA). The evaluation of the SLDA model was performed by cross-validation, obtaining an average percentage of correct classification of 100.0%, and of correct prediction of 89.3%. The results of this investigation suggest that above-mentioned esters, acids and alcohols could be used as markers of Malvazija istarska young wine quality.

The HS-SPME-GC-MS analysis of Fiano di Avellino (white wine, Southern Italy) and Aglianico del Vulture (red wine, Southern Italy) showed the presence of ethyl acetate, 2-methyl-1-propanol, 2-methyl-1-butanol (MB), 2-methylbutyl acetate (MBA), ethyl hexanoate (EH), diethyl butanedioate (DB), ethyl octanoate (EO) and ethyl decanoate (ED). UV irradiation of both the wines in a Pyrex vial with a 15-W low pressure mercury arc showed an extensive degradation of all the compounds. After 24 h irradiation in the red wine, ethyl acetate decreased from 208 mg L ―1 to 58 mg L ―1 , DB from 16.7 to 4 mg L ―1 , MBA from 19 to 3 mg L ―1 , 2-methyl-1-propanol disappeared and MB decreased from 796 to 92.5 mg L ― 1 . Only in the case of DB, MBA, EH, EO and ED in the red wine the degradation occurred after an initial increase of the concentrations of the esters. The irradiation of the esters in the presence of riboflavin showed a clear degradation of the esters (9%―17%). The irradiation of both the wines in the original bottles for 7 days showed an extensive degradation of all the volatile compounds observed in the wines. 2-Methyl-1-propanol disappeared while 90% of MB disappeared. The amount of the esters decreases in the range 65%―91%.

Summary 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.

Sulphur dioxide and mixtures of glutathione with caffeic acid or gallic acid were tested as inhibitors of the decrease of isoamyl acetate, ethyl hexanoate and linalool during storage of a model wine medium. Model wine samples were analysed by SPME and GC–MS. Isoamyl acetate, ethyl hexanoate and linalool decreased during storage of the model wine medium containing 0, 20, 40 or 60 mg/l free SO2. SO2 protected the three volatiles at 20 (isoamyl acetate), 40 (ethyl hexanoate) and 60 mg/l (linalool). Mixtures of glutathione with caffeic acid or gallic acid were also protective; they were more active at 10 + 30 mg/l than at 5 + 15 mg/l. Glutathione + caffeic acid was more effective than glutathione + gallic acid. In most cases, SO2 at 40 mg/l increased the protective effect of the mixtures. SO2 at 60 mg/l exhibited protective ability comparable to that of glutathione + gallic acid 5 + 15 mg/l. The present results indicate that SO2 protects some wine aroma volatiles, but at high concentrations. On the other hand, mixtures of the wine constituents glutathione + caffeic acid or gallic acid are more effective at concentrations similar to those existing in wines. Copyright © 2008 John Wiley & Sons, Ltd.

Various oxo-dimethylallyl compounds were prepared from intermediates which are obtained by the reaction of allylic Grignard reagents with carboxylic acid derivatives. For example, the reaction of prenylmagnesium chloride with ethyl hexanoate gave 3,3–dimethyl-4–prenyl-1-nonen-4–ol (1) in 92% yield. The thermolysis of 1 at the temperature of 693 K gave 2–methyl-2–decen-5–one (2) in 81% yield. Furthermore, 3,3–dimethyl-1-alken-4–ones (E) were prepared by the methylation of 1-alken-4-ones (C), which are obtained by the reaction of allylmagnesium chloride with carboxylic acids (A).

Summary To investigate the relationship between aroma delivery and perception, low-fat (LF) (0.1 g per 100 mL) and regular-fat (RF) (3.6 g per 100 mL) milk samples were prepared with the same amount of ethyl hexanoate. Sensory analysis was carried out using around ninety panellists (four replicates each) and simultaneous in vivo aroma delivery was measured for every sample. Panellists rated the fruity flavour intensity higher in LF samples using a paired comparison method (P

Summary Esters are quite important for the aroma of aged red wine as they contribute to the fruity complex nature of this wine. This research paper measured the development of esters during maturation of Merlot red wines. These wines had different amounts of turbidity. The wine was aged for 18 months either after filtration with diatomaceous earth or without filtration. Both American and French oak barrel were used for storage. The results obtained showed that the unfiltered wine had a greater concentration of esters at the end of the storage period than the filtered wine. Fatty acid and ethanol esters decreased more than isoamyl acetate, independently of filtration. Ethyl octanoate and ethyl decanoate decreased both in filtered and unfiltered wine. Isoamyl acetate was formed in unfiltered wine and ethyl butyrate and ethyl hexanoate decreased in filtered wine while they remained constant in unfiltered wine.

Aroma compounds in Chinese ‘Yanghe Daqu’ liquor were investigated with normal phase chromatography fractionation followed by gas chromatography–olfactometry (GC–O). Yanghe Daqu liquor was extracted with Freon 11, and then separated into acidic and neutral[sol ]basic fractions. The neutral[sol ]basic fraction was further separated into four fractions, using silica gel normal phase chromatography. Aroma compounds in each fraction were analysed by GC–O and GC–MS. The results showed that Yanghe Daqu liquor aroma was mainly contributed by esters and fatty acids. Among them, ethyl hexanoate (Osme value =15), ethyl butanoate (Osme value ≥14) were probably the most important esters, based on their Osme values. In addition, ethyl octanoate, 3-methylbutyl hexanoate and ethyl pentanoate could be important (Osme values ≥10). Acids with high Osme value included hexanoic, butanoic, 3-methylbutanoic and pentanoic acids. They contributed to sour, acid, cheesy and sweaty aromas. 1-Hexanol and 3-methylbutanol also had high Osme values. In addition, 4-ethylguaiacol, 4-methylguaiacol and 4-ethylphenol were identified in Yanghe Daqu liquor and they contributed to clove, sweet, smoky and goaty aromas. 1,1-Diethoxy ethane, 1,1-diethoxy-2-methylpropane and 1,1-diethoxy-3-methylbutane were identified and they gave fruity and floral aromas. Copyright © 2005 John Wiley & Sons, Ltd.

( ( ( (P < 0.05) and concentrations of 23 volatile compounds of 14 distillate fractions and 15 finished Piscos. Artificial 0.05) and concentrations of 23 volatile compounds of 14 distillate fractions and 15 finished Piscos. Artificial 0.05) and concentrations of 23 volatile compounds of 14 distillate fractions and 15 finished Piscos. Artificial 0.05) and concentrations of 23 volatile compounds of 14 distillate fractions and 15 finished Piscos. Artificial 0.05) and concentrations of 23 volatile compounds of 14 distillate fractions and 15 finished Piscos. Artificial fruit attribute, characteristic of the head fraction (FR1) can be tracked with esters. Linalool, main odor attribute of fruit attribute, characteristic of the head fraction (FR1) can be tracked with esters. Linalool, main odor attribute of fruit attribute, characteristic of the head fraction (FR1) can be tracked with esters. Linalool, main odor attribute of fruit attribute, characteristic of the head fraction (FR1) can be tracked with esters. Linalool, main odor attribute of fruit attribute, characteristic of the head fraction (FR1) can be tracked with esters. Linalool, main odor attribute of the 1st part of the heart (FR2) can be tracked with linalool molecule. The 2nd part of the heart (FR3) can be tracked the 1st part of the heart (FR2) can be tracked with linalool molecule. The 2nd part of the heart (FR3) can be tracked the 1st part of the heart (FR2) can be tracked with linalool molecule. The 2nd part of the heart (FR3) can be tracked the 1st part of the heart (FR2) can be tracked with linalool molecule. The 2nd part of the heart (FR3) can be tracked the 1st part of the heart (FR2) can be tracked with linalool molecule. The 2nd part of the heart (FR3) can be tracked with octanoic acid, decanoic acid, furfural and ethyl lactate, accounting for tails attribute. In blended and aged with octanoic acid, decanoic acid, furfural and ethyl lactate, accounting for tails attribute. In blended and aged with octanoic acid, decanoic acid, furfural and ethyl lactate, accounting for tails attribute. In blended and aged with octanoic acid, decanoic acid, furfural and ethyl lactate, accounting for tails attribute. In blended and aged with octanoic acid, decanoic acid, furfural and ethyl lactate, accounting for tails attribute. In blended and aged finished products, chemical markers accounting for the effects of distillate fractions were similar but not identical finished products, chemical markers accounting for the effects of distillate fractions were similar but not identical finished products, chemical markers accounting for the effects of distillate fractions were similar but not identical finished products, chemical markers accounting for the effects of distillate fractions were similar but not identical finished products, chemical markers accounting for the effects of distillate fractions were similar but not identical to the markers from samples obtained from the purely distilled samples. Chemical markers for FR1 are ethyl to the markers from samples obtained from the purely distilled samples. Chemical markers for FR1 are ethyl to the markers from samples obtained from the purely distilled samples. Chemical markers for FR1 are ethyl to the markers from samples obtained from the purely distilled samples. Chemical markers for FR1 are ethyl to the markers from samples obtained from the purely distilled samples. Chemical markers for FR1 are ethyl hexanoate, ethyl octanoate, ethyl decanoate. Differentiation between FR1 and FR2 is less evident than in the purely hexanoate, ethyl octanoate, ethyl decanoate. Differentiation between FR1 and FR2 is less evident than in the purely hexanoate, ethyl octanoate, ethyl decanoate. Differentiation between FR1 and FR2 is less evident than in the purely hexanoate, ethyl octanoate, ethyl decanoate. Differentiation between FR1 and FR2 is less evident than in the purely hexanoate, ethyl octanoate, ethyl decanoate. Differentiation between FR1 and FR2 is less evident than in the purely distilled samples due to the linalool and artificial fruit attribute correlation. Chemical markers for FR2, therefore, distilled samples due to the linalool and artificial fruit attribute correlation. Chemical markers for FR2, therefore, distilled samples due to the linalool and artificial fruit attribute correlation. Chemical markers for FR2, therefore, distilled samples due to the linalool and artificial fruit attribute correlation. Chemical markers for FR2, therefore, distilled samples due to the linalool and artificial fruit attribute correlation. Chemical markers for FR2, therefore, include linalool and esters ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The blending of the 2nd part of include linalool and esters ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The blending of the 2nd part of include linalool and esters ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The blending of the 2nd part of include linalool and esters ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The blending of the 2nd part of include linalool and esters ethyl hexanoate, ethyl octanoate, and ethyl decanoate. The blending of the 2nd part of the heart (FR3) can be tracked with 2-phenylethanol, ethyl lactate, and decanoic acid. Oak aging was tracked with the heart (FR3) can be tracked with 2-phenylethanol, ethyl lactate, and decanoic acid. Oak aging was tracked with the heart (FR3) can be tracked with 2-phenylethanol, ethyl lactate, and decanoic acid. Oak aging was tracked with the heart (FR3) can be tracked with 2-phenylethanol, ethyl lactate, and decanoic acid. Oak aging was tracked with the heart (FR3) can be tracked with 2-phenylethanol, ethyl lactate, and decanoic acid. Oak aging was tracked with eugenol and whisky lactones, while 5-hydroxy-methyl-2-furfural accounted for added caramel. eugenol and whisky lactones, while 5-hydroxy-methyl-2-furfural accounted for added caramel. eugenol and whisky lactones, while 5-hydroxy-methyl-2-furfural accounted for added caramel. eugenol and whisky lactones, while 5-hydroxy-methyl-2-furfural accounted for added caramel. eugenol and whisky lactones, while 5-hydroxy-methyl-2-furfural accounted for added caramel.

Volatile compositions of 'Marion' and 'Thornless Evergreen' blackberries from 3 growing seasons were analyzed using gas chromatography-flame ionization detection (GC-FID) and GC-mass spectrometry (GC-MS). Although seasonal variations were present for both cultivars, it was generally observed that the most abundant volatiles in 'Marion' blackberry were acetic, 2/3-methylbutanoic, hexanoic and decanoic acids, ethanol, and linalool, whereas the most abundant volatiles in 'Thornless Evergreen' were 2-heptanol, hexanol, octanol, α-pinene, nopol, and p-cymen-8-ol. Compared with 'Marion,' 'Thornless Evergreen' contained significantly more total volatiles, especially in alcohols, terpenoids, and phenols, whereas 'Marion' contained more organic acids. Odor activity values (OAVs) were determined to identify each cultivar's most potent odorants. The compounds with the high odor activity values (OAV > 10) in 'Marion' were ethyl hexanoate, β-ionone, linalool, 2-heptanone, 2-undecanone, α-ionone, and hexanal. The compounds with the high odor activity values (OAV > 10) in 'Thornless Evergreen' were ethyl hexanoate, 2-heptanone, ethyl 2-methylbutanoate, 2-heptanol, 3-methylbutanal, α-pinene, limonene, p-cymene, linalool, t-2-hexenal, myrtenol, hexanal, 2-methylbutanal, and sabinene.

Stage of lactation, use of bulk milk or milk from individual flocks, and cheese-making in farmhouse or industrial factory are important factors affecting the production and quality of Idiazabal cheese. The volatile composition of cheese samples made from raw ewe's milk in farmhouses or industrial plants at two different times of the year and aged for 90 and 180 days was analysed by dynamic headspace coupled to GC-MS. Short-chain fatty acids, primary and secondary alcohols, methyl ketones and ethyl esters were the most abundant compounds in the aroma of Idiazabal cheese samples. Differences in the volatile composition were found between farmhouse and industrial cheeses made at different times of the year and ripened for 90 or 180 days. Likewise, the sensory profiles of the farmhouse and industrial cheeses were significantly different, regardless of the time of the year and ripening time. The results for the principal component analysis (PCA) performed on the sensory attributes of the cheese samples showed two PCs defined as 'farmhouse flavour factor' and 'industrial flavour factor'. Farmhouse cheeses showed high scores for buttery, milky and toasty odours, and buttery and nutty flavours, whereas industrial cheeses showed high scores for sharp, rennet and brine odours, and rennet and rancid flavours. The percentages of methyl ketones such as 3-hydroxy-2-butanone, 2-butanone, 2-pentanone and 2-heptanone, and acids such as n-propanoic, 2-methylpropanoic and 3-methylbutanoic acids were higher in farmhouse cheeses than in industrial cheeses. On the other hand, the percentages of esters such as ethyl butanoate and ethyl hexanoate, and alcohols such as 3-methyl-1-butanol, and acids like n-hexanoic acid were higher in industrial cheeses than in farmhouse cheeses. Relationships between sensory attributes and volatile compounds were studied on the basis of the differences found in sensory profile and volatile composition between farmhouse and industrial cheeses.

The solubility of nine aroma compounds (acetone, 2-butanone, 2-hexanone, 2-octanone, ethyl acetate, ethyl butanoate, ethyl hexanoate, n-hexanal, and n-hexanol) in both water and various aqueous solutions was measured at 25 °C using the mutual solubility method. The aqueous solutions consisted of sucrose, glucose, sorbitol, glycerol, polyethylene glycol 200, or maltodextrins at different concentrations. Aroma solubility in water decreased with increased hydrophobicity. For aroma molecules which have the same number of carbon atoms in their structure, aqueous solubility decreased as follows: aldehyde > methyl ketone > alcohol > ethyl ester. When using a group contribution method, the estimated solubility of ethyl esters and methyl ketones in water was, respectively, underestimated and overestimated. Compared to water, the solubility of the volatile molecules in aqueous solutions was higher in the aqueous polyols solutions than in the carbohydrate solutions, although solubility decreased as substrate concentration increased. Aqueous solutions properties, such as water activity, also influenced aroma compound solubility. Copyright © 2004 John Wiley & Sons, Ltd.

The effect of UV-induced stress on the volatile aroma compounds in cut pineapple was compared with that of storage at 4 °C for 24 h. Eighteen volatile compounds were identified by solid-phase microextraction (SPME) in fresh-cut pineapple. Methyl-2-methylbutanoate, methyl hexanoate, methyl 5-hexenoate, ethyl hexanoate and ethyl 5-hexenoate were the major aroma compounds. Storage at 4 °C for 24 h, and exposure of cut fruit to UV radiation for 15 min caused a considerable decrease in the concentration of esters and increase in the relative amount of copaene. This sesquiterpene, when added to crushed cantaloupe melon (0.1 mg g−1), inhibited microbial growth in the fruit over a period of 24 h at 20 °C. Cis- and trans-ocimene were present in the fruit but their production was not photo-induced by UV irradiation. Ocimene, however, was a potent antimicrobial agent that killed microorganisms when added to the crushed fruit and stored at 20 °C for 24 h. The results indicate that sesquiterpene phytoalexins could contribute to the defense mechanism in wounded pineapple tissue. Published in 2004 for SCI by John Wiley & Sons, Ltd.

WOS: 000223675500007, The volatile flavour constituents of mandarin wine obtained from clementine (Citrus reticula Blanco) were analysed by headspace solid-phase microextraction (HS-SPME) and immersion solid-phase microextraction (Im-SPME) coupled to GC-MS. A total of 19 volatiles, including eight esters, four higher alcohols, three monoterpenes and four furfural compounds, were identified in wine. The HS-SPME technique showed a higher sensitivity than Im-SPME. The major constituents found in wine volatiles using HS-SPME were ethyl octanoate, ethyl decanoate, isoamyl alcohol, ethyl hexanoate and isoamyl acetate, respectively. Copyright (C) 2004 John Wiley Sons, Ltd.

The effect of elevated carbon dioxide on fruit quality and aroma volatile composition in field-grown strawberries (Fragaria × ananassa Duch) was studied. Elevating the ambient CO2 concentration (ambient + 300, and ambient +600 µmol mol−1 CO2) resulted in high fruit dry matter, fructose, glucose and total sugar contents and low citric and malic acid contents. High CO2 growing conditions significantly enhanced the fruit content of ethyl hexanoate, ethyl butanoate, methyl hexanoate, methyl butanonate, hexyl acetate, hexyl hexanoate, furaneol, linalool and methyl octanoate. Thus, the total amounts of these compounds were higher in berries grown in CO2-enriched conditions than those grown in ambient conditions. The highest CO2 enrichment (600 µmol mol−1) condition yielded fruit with the highest levels of these aroma compounds. Copyright © 2004 Society of Chemical Industry

The aroma profiles of Oregon Pinot Noir wines were investigated with aroma extract dilution analysis (AEDA). The wines were extracted with pentane-diethyl ether, the aromas were distilled using solvent-assisted flavour evaporation (SAFE) and separated into acidic/water-soluble and neutral/basic fractions. In the acidic/water-soluble fraction, 2-phenylethanol and 3-methyl-1-butanol showed the highest AEDA values, followed by 2-methylpropanoic acid, butanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, 2-methylpropanol, hexanol, trans-3-hexenol, cis-3-hexenol, benzyl alcohol, 3-methylthio-1-propanol, 3-ethylthio-1-propanol, linalool and geraniol (all with FD ≥ 64). In the neutral/basic fraction, ethyl 2-methylpropanoate, ethyl butanoate, 3-methylbutyl acetate, ethyl hexanoate, and benzaldehyde had very high AEDA values (all with FD ≥ 64), followed by ethyl 3-methylbutanoate, 3-methylbutyl 2-methylpropanoate, ethyl octanoate, ethyl decanoate, benzyl acetate, phenylethyl formate, phenylethyl acetate, ethyl dihydrocinnamate, ethyl anthranilate, 3-methylthio-1-propanal, citronellal, whisky lactone and γ-nonalactone (all with FD ≥ 16). Overall, the results indicated that there is no single compound that characterizes the aroma of Pinot Noir, and that the characteristic aroma comes from a blend of numerous compounds. Copyright © 2004 John Wiley & Sons, Ltd.

Different model food systems were made with iota- and kappa-carrageenans. Their viscoelastic characteristics were determined and four different systems were classified according to their gel strength by a sensory panel. The sensory results were in total agreement with the rheological parameters (storage and loss modulus). Flavour molecules from different chemical classes and with different chain lengths for the same chemical class were then incorporated in two of the most different systems. These samples were compared for their ortho- and retronasal intensities. No significant difference was perceived in odour intensity, except for ethyl hexanoate, which was found to be retained by iotacarrageenans. Nevertheless, in-mouth aroma perception was significantly different between the two systems. Aroma was perceived more intensely in the less firm system. The release kinetic results are interpreted in terms of partition and mass transfer coefficients. Sensory differences are not totally explained by physicochemical results, which suggests that interactions between senses may occur.

Release of 6 flavor molecules from cyclodextrins (CyDs) was studied in 3.6% aqueous ethanol over the temperature range 5 to 85°C. Headspace measurements of l-menthol, ethyl butyrate, ethyl hexanoate, benzaldehyde, citral, and methyl anthranilate above individual solutions of each, containing 1% or 0.1% of α-, β-, and γ-CyD, were made relative to control systems containing no CyD. Significant interactions were observed even at elevated temperature and flavor/CyD binding often showed strong temperature dependence. Results were generally substantiated by sensory evaluation. Our data suggest that CyDs may alter the sensory profile of a food and the effect maybe temperature-dependent.