Nonvolatile Matrix Research Articles

Furfural analysis of aqueous and oily foodstuffs using a single modified paper for combined headspace extraction, derivatization and paper spray mass spectrometry

Furfurals, including 2-furaldehyde, 5-methylfurfural and 5-hydroxymethylfurfural, widely exist in carbohydrate-rich daily foods, and may have toxic effects on humans. Here, a new headspace extraction-paper spray mass spectrometry (HSPS-MS/MS) method was established for furfural detection, in which the extraction and derivatization of volatiles with pre-loaded derivatization agent on paper tips is combined with paper spray mass spectrometry for detection. By this simple and cheap approach, interference of non-volatile matrix compounds is prevented, and the derivatization agent improves electrospray-type ionization efficiency, thus increasing selectivity and sensitivity. The approach was optimized, by investigating positioning during extraction, extraction duration, derivatization agent, addition of internal standard for quantification and finally validated. For this, the developed method was benchmarked against HPLC-UV and could obtain detections limits of 0.32–0.40 μg mL−1 for 2-furaldehyde, 5-methylfurfural and 5-hydroxymethylfurfural in olive oil. Moreover, fast screening of free furfurals in soy sauce, coffees and teas was demonstrated with the HSPS-MS/MS method.

The remarkable effects of the non-volatile matrix of wine on the release of volatile compounds evaluated by analysing their release to the headspaces

Six Spanish wines with different wine-making styles were completely dearomatised and later reconstituted to their original volume with a standard volatile solution containing 15 wine aroma compounds with broad differences in physicochemical characteristics. The headspace composition of the reconstituted wines was evaluated using an automated dynamic headspace (DHS) method combined with thermal desorption (TD) and gas chromatography–mass spectrometry (GC–MS). This method provides a snapshot of the volatile profiles transferred to the headspace in non-equilibrium conditions. The results showed that the non-volatile matrix of the wine significantly affected the transference to the headspace of the 15 aroma compounds. Differences between wines for butanoic and hexanoic acids, DMS and vanillin are above factors 5, 4 or 3, respectively, while for ethyl acetate, ethyl decanoate, 3-methylbutan-1-ol, 2-phenylethan-1-ol or 4-ethylphenol are close to a factor 2. Only ethyl butanoate was uniformly transferred. The release of DMS was related to copper levels, while pH explained part of the release of fatty acids. However, most effects of volatility are difficult to explain. Results strongly indicate that a sample-specific correction for volatility is required to interpret the sensory effects of aroma volatiles.

Dealcoholized Wine: A Scoping Review of Volatile and Non-Volatile Profiles, Consumer Perception, and Health Benefits

AbstractThe dealcoholization technique has gained more attention in the wine industry as it can significantly influence wine compositions and quality beyond alcohol level reduction. However, the changes occurring in the various processes of dealcoholization are not fully understood yet. This work summarizes the literature published in the last 10 years (2013–2023) about changes in color, sulfur dioxide (SO2), phenolic composition, losses of desirable volatile aroma compounds, and sensory characteristics of wine after the removal of ethanol by different processes/techniques. Several factors can influence the final characteristics of wine during the process, including physico-chemical parameters such as the initial alcohol level, the retention properties of the wine non-volatile matrix, and the characteristics of aroma components. Additionally, the quality of dealcoholized wine can be affected by the choice of dealcoholization techniques, distillation temperature, operating pressure, and membrane properties, including filtration and pore size. Low- and zero-alcohol products have the potential to expand the market and cater to diverse consumer segments. This comprehensive review would help winemakers in choosing the best techniques to produce dealcoholized wine, limiting the adverse effects, and meeting the needs of consumers.

Collision-Induced Unfolding, Tandem MS, Bottom-up Proteomics, and Interactomics for Identification of Protein Complexes in Native Surface Mass Spectrometry.

Endogenously occurring salts and nonvolatile matrix components in untreated biological surfaces can suppress protein ionization and promote adduct formation, challenging protein identification. Characterization of labile proteins within biological specimens is particularly demanding because additional purification or sample treatment steps can be time-intensive and can disrupt noncovalent interactions. It is demonstrated that the combined use of collision-induced unfolding, tandem mass spectrometry, and bottom-up proteomics improves protein characterization in native surface mass spectrometry (NSMS). This multiprong analysis is achieved by acquiring NSMS, MS/MS, ion mobility (IM), and bottom-up proteomics data from a single surface extracted sample. The validity of this multiprong approach was confirmed by the successful characterization of nine surface-deposited proteins, with molecular weights ranging from 8 to 147 kDa, in two separate mixtures. Bottom-up proteomics provided a list of proteins to match against observed proteins in NSMS and their detected subunits in tandem MS. The method was applied to characterize endogenous proteins from untreated chicken liver samples. The subcapsular liver sampling for NSMS analysis allowed for the detection of endogenous proteins with molecular weights of up to ∼220 kDa. Moreover, using IM-MS, collision cross sections and collision-induced unfolding pathways of enzymatic proteins and protein complexes of up to 145 kDa were obtained.

Effect of molar mass and size of non-alcoholic beer fractions and their relevance toward palate fullness intensity

Palate fullness intensity and mouthfeel descriptors are essential sensory characteristics of non-alcoholic beers (NABs). The descriptor’s perception might be influenced by the molar distribution of the non-volatile matrix in cereal-based beverages like NABs. However, only limited information is available on the molar mass of different substances in NABs. This study investigated the role of weight average molar mass (Mw) and size of NABs fractions and their relation to sensory perception. Industrialized bottom-fermented NABs (n = 28) from the German market and NABs produced by different methods were used in this study. A trained sensory panel evaluated palate fullness intensity, mouthfeel, and basic taste descriptors (as additional quality parameters). Asymmetric flow field-flow fractionation was used to fractionate NABs, while Mw was determined by multi-angle light scattering and differential refractive index detectors. The NABs were fractionated into three groups containing different substances: proteins, proteins-polyphenol complexes (P-PC) and low molar mass (non-)starch polysaccharides (LN-SP), and high molar mass (non-)starch polysaccharides (HN-SP). The Mw range of proteins was 18.3–41 kDa, P-PC and LN-SP 43–122.6 kDa, and HN-SP 0.40–2.18·103 kDa. Harmony, defined as the sweet and sour ratio, influenced the palate fullness intensity perception. In the harmonic samples (sour/sweet sensory balanced), the size of HN-SP (> 25 nm) showed a positive correlation to palate fullness intensity. The results suggest the importance of dextrins, arabinoxylan, and β-glucan in modulating the sensory characteristics of harmonic bottom-fermented NABs.

Decoding the Specific Roasty Aroma Wuyi Rock Tea (Camellia sinensis: Dahongpao) by the Sensomics Approach.

Aroma extract dilution analysis was performed on volatile fractions extracted from a freshly prepared Dahongpao (DHP) tea infusion using solvent-assisted flavor evaporation, yielding 65 odor-active domains with flavor dilution factors ranging between 32 and 32,768. In addition, six aromatic substances were captured by headspace analysis. Quantitation of 54 compounds by an internal standard method and stable isotope dilution assays revealed that the concentrations of 32 odorants exceeded their respective orthonasal odor threshold values in tea infusion. The results of odor activity values (OAVs) suggested that 2-metylbutanal (malty) and γ-hexalactone (coconut-like) had the highest OAVs (248 and 154). Eight odorants including γ-hexalactone (OAV 154), methyl 2-methylbutanoate (59), phenylacetic acid (7.2), acetylpyrazine (5.7), 2-methoxyphenol (3.4), p-cresol (2.7), 2,6-diethylpyrazine (2.7), and vanillin (1.8) were newly identified as key odorants in DHP tea infusion. An aroma recombination model in a non-volatile matrix extracted from tea infusion satisfactorily mimicked the overall aroma of DHP tea infusion, thereby confirming the identification and quantitative experiments. Omission experiments verified the obvious significance of 6-methyl-5-hepten-2-one (OAV 91), 2-ethyl-3,5-dimethylpyrazine (19), 4-hydroxy-2,5-dimethylfuran-3(2H)-one (13), and acetylpyrazine (5.7) as key odorants for the special roasty and caramel-like aroma of DHP tea.

Back Cover: Single bubble in‐tube microextraction coupled with capillary electrophoresis

DOI: 10.1002/elps.202100216 The cover picture shows three modes of headspace liquid phase microextraction (HS-LPME) in-line coupled with CE. Headspace single drop microextraction (HS-SDME)-CE: When a single drop of the acceptor phase (blue) is formed at the inlet of a separation capillary filled with a run buffer (pale pink), the analytes evaporated from the sample donor solution (green) into the HS are extracted into the drop leaving less- or non-volatile matrix components in the sample. After extraction, a portion of the drop containing enriched analytes is injected into the capillary for CE analysis. Due to the large volume ratio between the sample donor solution and the acceptor drop, and the large surface-to-volume ratio of the drop, the sample enrichment factors obtained with SDME are quite high for a given extraction time, compared with other conventional LPME techniques. However, it is critical to maintain the drop stably attached to the capillary during extraction and thus it is rather difficult to carry out SDME for a long time especially under harsh conditions such as elevated temperature. Headspace in-tube microextraction (HS-ITME)-CE: Using a liquid plug in the capillary inlet as an acceptor phase instead of a hanging drop, the shortcomings of the hanging drop can be resolved. In HS-ITME-CE, the capillary inlet containing the acceptor plug is simply placed in the HS above a sample solution. Since the acceptor phase is well protected by the capillary, a long extraction at a temperature as high as 90°C can be performed with ease. Furthermore, since the enriched acceptor plug is already inside the capillary, the whole extract can be utilized for the subsequent CE analysis without additional injection step. Single bubble in-tube microextraction (SB-ITME)-CE: For a short extraction time, the extraction efficiency of HS-SDME or HS-ITME was not maximized because it takes some time for the analytes to fill the HS and reach saturated concentrations, especially for compounds of low volatility. By using a single bubble as a micro-HS formed at the inlet of a separation capillary immersed in the sample donor solution, the HS extraction can be expedited without waiting for the HS equilibration. Since the surface-to-volume ratio of the submicroliter bubble is much higher than that of a conventional HS of a few milliliters or more, the analyte concentrations in the bubble can be replenished much more rapidly for short extraction times. SB-ITME demonstrated higher sample enrichments than HS-ITME for a short HS extraction of chlorophenols in water.

Impact of tannins on intraoral aroma release and retronasal perception, including detection thresholds and temporal perception by taste, in model wines

Tannins, as an important wine nonvolatile matrix component, can cause astringency, which may affect aroma perception through cross-modal interactions during wine consumption. An aromatic model wine with tannin extracts was evaluated by intraoral aroma release and sensory analysis after wine spitting. Overall, tannin extracts could significantly decrease all initial aroma release, while they could not reduce most aroma release at 150 s after wine spitting. Regarding the sensory evaluation results, the retronasal detection threshold of most aromas increased. The temporal aroma intensity showed a significant decrease at early time points and was almost unaffected at later time points. In addition, temporal dominance of sensation (TDS) curves revealed that the presence of astringency could reduce the dominant time of most aromas. Therefore, although there was good consistency between instrumental analysis and sensory evaluation, the effect of astringency induced by tannins on retronasal perception cannot be ignored.

Multi-residue method validation and safety evaluation of pesticide residues in seed spices cumin (Cuminum cyminum) and coriander (Coriandrum sativum) by gas chromatography tandem mass spectrometry (GC–MS/MS)

The manuscript reports comprehensive multi-residue determination of 215 pesticides in two commercially important Indian spices, Cumin (Cuminum cyminum) and Coriander (Coriandrum sativum) by GC–MS/MS analysis. The proposed method involved liquid–liquid extraction with acetonitrile, d-SPE clean-up and final reconstitution of extract in ethyl acetate. d-SPE clean-up with PSA and C18 minimized the matrix effects by 40 and 16%, respectively. Reconstitution of final extract reduced the non-volatile matrix co-extractives by 36–40%. The method was validated as per SANTE/12682/2019 and recoveries at 10, 25 and 50 μg kg−1 were within 70–120% with RSD ≤ 20%. A fit for purpose method LOQ of 10 μgkg−1 was achieved for 85% of analytes. The method was successfully applied for comprehensive screening of cumin and coriander market samples. The calculated TMDI for acute and chronic exposure assessment were less than calculated MPI in respective matrices and therefore did not cause any adverse effect to consumers.

Techniques for Dealcoholization of Wines: Their Impact on Wine Phenolic Composition, Volatile Composition, and Sensory Characteristics.

The attention of some winemakers and researchers over the past years has been drawn towards the partial or total dealcoholization of wines and alcoholic beverages due to trends in wine styles, and the effect of climate change on wine alcohol content. To achieve this, different techniques have been used at the various stages of winemaking, among which the physical dealcoholization techniques, particularly membrane separation (nanofiltration, reverse osmosis, evaporative perstraction, and pervaporation) and thermal distillation (vacuum distillation and spinning cone column), have shown promising results and hence are being used for commercial production. However, the removal of alcohol by these techniques can cause changes in color and losses of desirable volatile aroma compounds, which can subsequently affect the sensory quality and acceptability of the wine by consumers. Aside from the removal of ethanol, other factors such as the ethanol concentration, the kind of alcohol removal technique, the retention properties of the wine non-volatile matrix, and the chemical-physical properties of the aroma compounds can influence changes in the wine sensory quality during dealcoholization. This review highlights and summarizes some of the techniques for wine dealcoholization and their impact on wine quality to help winemakers in choosing the best technique to limit adverse effects in dealcoholized wines and to help meet the needs and acceptance among different targeted consumers such as younger people, pregnant women, drivers, and teetotalers.

Quantification of Volatile Compounds in Wines by HS-SPME-GC/MS: Critical Issues and Use of Multivariate Statistics in Method Optimization

The aim of this review is to explore and discuss the two main aspects related to a HeadSpace Solid Phase Micro-Extraction Gas-Chromatography/Mass-Spectrometry (HS-SPME-GC/MS) quantitative analysis of volatile compounds in wines, both being fundamental to obtain reliable data. In the first section, recent advances in the use of multivariate optimization approaches during the method development step are described with a special focus on factorial designs and response surface methodologies. In the second section, critical aspects related to quantification methods are discussed. Indeed, matrix effects induced by the complexity of the volatile profile and of the non-volatile matrix of wines, potentially differing between diverse wines in a remarkable extent, often require severe assumptions if a reliable quantification is desired. Several approaches offering different levels of data reliability including internal standards, model wine calibration, a stable isotope dilution analysis, matrix-matched calibration and standard addition methods are reported in the literature and are discussed in depth here.

A comparative study of partial dealcoholisation versus early harvest: Effects on wine volatile and sensory profiles

Two Verdelho and Petit Verdot wines were produced from sequential harvests of grapes. The alcohol concentration of early harvest (EH) and late harvest (LH) wines were respectively 9% and 13.5% v/v for Verdelho, and 10.5% and 13% v/v for Petit Verdot. LH wines were dealcoholised to match the same alcohol level of EH samples using a combined reverse osmosis-evaporative perstraction process. In dealcoholised wines, there was a decrease in volatile compounds (esters particularly) compared to LH treatments. For both varieties, the sensory attribute ratings for overall aroma intensity and alcohol mouthfeel also decreased following dealcoholisation. Dealcoholised wines were distinctively different from both LH and EH wines even though these wines had similar alcohol level to EH wines. When dealcoholisation is considered for high-alcohol wines, it is important to consider that membrane effects can significantly change depending on the wine non-volatile matrix composition and the level of alcohol reduction required.

Correlation Between Sensory Descriptive Analysis and Volatile Composition of Beer Using Multivariate Analysis: The Effect of the Nonvolatile Matrix on the Sensory Perception and Volatile Fraction Behavior

ABSTRACTThe effect of carbohydrate and protein content on the volatile compound release and sensory perception of four selected volatile compounds (isoamyl acetate [banana], ethyl hexanoate [apple], myrcene [dry-hop], benzaldehyde [almond]) from a model beer solution was investigated. Sensory attributes were evaluated using a trained sensory panel, while the concentration of volatile compounds were determined by 1) solid phase microextraction (SPME), 2) solid phase dynamic extraction (SPDE) coupled to gas chromatography mass spectrometry (GC/MS), and 3) stir bar sorptive extraction (SBSE) coupled to gas chromatography flame ionization (GC/FID). In addition, sensory and analytical results were correlated by multivariate analysis. Model beer samples with low levels of proteins and high levels of carbohydrates possessed the highest concentrations of isoamyl acetate, benzaldehyde, and ethyl hexanoate. Myrcene was only influenced by carbohydrate content, with a higher concentration recovered at a lower level of carbohydrate. From sensory analysis, apple and banana aroma attributes were perceived as less intense at the low protein content (P ≤ 0.05). Dry-hop aroma was perceived as more intense in samples with low carbohydrate content (P ≤ 0.05). Multivariate analysis showed a weak correlation between the sensory and instrumental data. The results illustrate that sensory perception and volatile fraction behaviors are influenced by the nonvolatile components and also demonstrate the need for caution when correlating instrumental to sensory analysis.

Prototype of an Interface for Hyphenating Distillation with Gas Chromatography and Mass Spectrometry.

Chemical analysis of complex matrices-containing hundreds of compounds-is challenging. Two-dimensional separation techniques provide an efficient way to reduce complexity of mixtures analyzed by mass spectrometry (MS). For example, gasoline is a mixture of numerous compounds, which can be fractionated by distillation techniques. However, coupling conventional distillation with other separations as well as MS is not straightforward. We have established an automatic system for online coupling of simple microscale distillation with gas chromatography (GC) and electron ionization MS. The developed system incorporates an interface between the distillation condenser and the injector of a fused silica capillary GC column. Development of this multidimensional separation (distillation-GC-MS) was preceded by a series of preliminary off-line experiments. In the developed technique, the components with different boiling points are fractionated and instantly analyzed by GC-MS. The obtained data sets illustrate dynamics of the distillation process. An important advantage of the distillation-GC-MS technique is that raw samples can directly be analyzed without removal of the non-volatile matrix residues that could contaminate the GC injection port and the column. Distilling the samples immediately before the injection to the GC column may reduce possible matrix effects-especially in the early phase of separation, when molecules with different volatilities co-migrate. It can also reduce losses of highly volatile components (during fraction collection and transfer). The two separation steps are partly orthogonal, what can slightly increase selectivity of the entire analysis.

Impact of APCI ionization source in liquid chromatography tandem mass spectrometry based tissue distribution studies.

Measurement of test article concentration in tissue samples has been an important part of pharmacokinetic study and has helped to co-relate pharmacokinetic/pharmacodynamic relationships since the 1950s. Bioanalysis of tissue samples using LC-MS/MS comes with unique challenges in terms of sample handling and inconsistent analyte response owing to nonvolatile matrix components. Matrix effect is a phenomenon where the target analyte response is either suppressed or enhanced in the presence of matrix components. Based on previous reports electrospray ionization (ESI) mode of ionization is believed to be more affected by matrix components than atmospheric pressure chemical ionization (APCI) or atmospheric pressure photoionization. To explore the impact of ionization source with respect to bioanalysis of tissue samples, five structurally diverse compounds - atenolol, verapamil, diclofenac, propranolol and flufenamic acid - were selected. Quality control standards were spiked into 10 different biological matrices like whole blood, liver, heart, brain, spleen, kidney, skeletal muscle, eye and skin tissue and were quantified against calibration standards prepared in rat plasma. Quantitative bioanalysis was performed utilizing both APCI and ESI mode and results were compared. Quality control standards when analyzed with APCI mode were found to be more consistent in terms of accuracy and precision as compared with ESI mode. Additionally, for some instances, up to 20-fold broader dynamic linearity range was observed with APCI mode as compared with ESI mode. As phospholid interferences have poor response in APCI mode, protein precipitation extraction technique can be used for multimatrix quantitation, which is more amenable to automation. The approach of multiple biological matrix quantitation against a single calibration curve helps bioanalysts to reduce turnaround time. Copyright © 2016 John Wiley & Sons, Ltd.

Changes in volatile composition and sensory attributes of wines during alcohol content reduction.

A desirable sensory profile is a major consumer driver for wine acceptability and should be considered during the production of reduced-alcohol wines. Although various viticultural practices and microbiological approaches show promising results, separation technologies such as membrane filtration, in particular reverse osmosis and evaporative perstraction, in addition to vacuum distillation, represent the most common commercial methods used to produce reduced-alcohol wine. However, ethanol removal from wine can result in a significant loss of volatile compounds such as esters (ethyl octanoate, ethyl acetate, isoamyl acetate) that contribute positively to the overall perceived aroma. These losses can potentially reduce the acceptability of the wine to consumers and decrease their willingness to purchase wines that have had their alcohol level reduced. The change in aroma as a result of the ethanol removal processes is influenced by a number of factors: the type of alcohol reduction process; the chemical-physical properties (volatility, hydrophobicity, steric hindrance) of the aroma compounds; the retention properties of the wine non-volatile matrix; and the ethanol level. This review identifies and summarises possible deleterious influences of the dealcoholisation process and describes best practice strategies to maintain the original wine composition. © 2016 Society of Chemical Industry.

Analysis of volatile phenols in alcoholic beverage by ethylene glycol-polydimethylsiloxane based stir bar sorptive extraction and gas chromatography–mass spectrometry

An ethylene glycol (EG)/polydimethylsiloxane (PDMS) copolymer based stir bar sorptive extraction (SBSE)-GC–MS method was developed for the analysis of volatile phenols (4-ethylphenol, 4-vinylphenol, 4-ethylguaiacol, and 4-vinylguaiacol) in alcoholic beverages. The beverage samples were diluted with phosphate buffer (1M, pH 7) and extracted with an EG/PDMS stir bar. Volatile phenols were thermally desorbed and analyzed by GC–MS. Parameters affecting extraction efficiency were studied including ionic strength, pH, extraction time, ethanol content and nonvolatile matrix. Good correlation coefficients with R2 in the range of 0.994–0.999 were obtained for volatile phenol concentration of 5–500μg/L. Recovery for all phenols were from 95.7% to 104.4% in a beer matrix and 81.4% to 97.6% in a wine matrix. The method had a standard deviation less than 5.8% for all volatile phenols. The limit of quantification (LOQs) in beer samples was lower than 3μg/L. The method was further applied to analyze the concentrations of volatile phenols in beer, wine and other alcoholic beverage samples.

Transcriptional characteristics associated with lichenysin biosynthesis in Bacillus licheniformis from Chinese Maotai-flavor liquor making.

This work investigated the biosynthetic mechanism of lichenysin, the newly identified nonvolatile matrix component in Chinese liquors. Transcriptomes were analyzed in three producers, Bacillus licheniformis CGMCC 3961, 3962, and 3963, which were isolated from Maotai-flavor liquor-making process and produced 386.3, 553.5, and 795.2 μg/L lichenysin in a simulative liquor fermentation process. Lichenysin synthetase genes lchAA-AD in these three producers were expressed much more highly than those of the nonproducer B. licheniformis ATCC 14580 (>18.4-fold). In addition, ABC transporters were the most significant responsive metabolic pathway, and the expression levels of peptide transporter genes dppABCDE all increased more than 19.2-fold. When B. licheniformis CGMCC 3963 was cultured in synthetic medium, the expression of dppABCDE and lichenysin both increased with the addition of casein hydrolysate (containing various peptides). This indicated that peptide would act as a substrate for lichenysin synthesis. This work sheds new light on the mechanism for lichenysin biosynthesis.

Lichenysin, a cyclooctapeptide occurring in Chinese liquor jiannanchun reduced the headspace concentration of phenolic off-flavors via hydrogen-bond interactions.

Nonvolatile compounds play important roles in the quality of alcoholic beverages. In our previous work, a type of cyclooctapeptide lichenysin was newly identified in Chinese strong-aroma type liquor. In this work, it was found that lichenysin could selectively affect aroma volatility in strong-aroma type (Jiannanchun) liquor. Interaction of lichenysin and volatile phenolic compounds (off-odors in strong-aroma type liquor) was characterized using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). HS-SPME results indicated that lichenysin very efficiently suppressed the volatility of phenolic compounds by 36-48% (P < 0.05). Thermodynamic analysis showed that the binding process was mainly mediated by hydrogen bonding. Furthermore, the mixture of lichenysin and 4-ethylguaiacol revealed intermolecular cross peaks between the aH (Val) of lichenysin and the 1H of 4-ethylguaiacol, by using nuclear Overhauser effect spectroscopy. This study will help to further understand the interaction mechanisms between flavor and nonvolatile matrix components in Chinese liquors.

Effect of human saliva and sip volume of coffee brews on the release of key volatile compounds by a retronasal aroma simulator

The influence of human saliva and sip volume on aroma release in coffee brew was studied under mouth-simulated conditions. 24 aroma compounds of coffee brew were monitored and quantified in dynamic headspace of four different coffee brews by SPME–GC–MS in selective ion monitoring (SIM) modality.In the first part of our study, American, Neapolitan, moka and espresso coffee brews showed a different partition of aroma compounds when coffee brew comes into contact with saliva, with respect to the initial amount of volatiles analyzed by the orthonasal way. In addition, every brewing technique seems to imply a different behavior in the aroma release.In the second part, a significant influence of coffee sip volume on aroma headspace was observed. By analyzing the headspace concentration of aroma compounds after retronasal aroma simulation assay, an increase was obtained for some aldehydes assuming 25mL coffee in one sip, while when smaller sips were considered, the aldehyde release decreased and the levels of β-damascenone and 4-vinylguaiacol increased. The different aroma release could not be attributed to direct action of salivary constituents, but rather to the modification of volatile partition into the different phases of coffee brew caused by the presence of saliva. This modification could be mainly related to the chemical properties of volatile compounds and to the non-volatile matrix composition of different coffee brews, which affects the partitioning of volatile compounds and their perception.