ORCID Profile
0000-0002-7054-0374
Current Organisation
University of Adelaide Waite Campus
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Horticultural Production | Oenology and Viticulture | Wine Chemistry and Wine Sensory Science | Plant Physiology
Wine Grapes | Expanding Knowledge in the Agricultural and Veterinary Sciences | Beverages (excl. Fruit Juices) |
Publisher: Elsevier BV
Date: 04-2020
Publisher: MDPI AG
Date: 10-05-2018
Publisher: American Chemical Society (ACS)
Date: 11-05-2021
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.PLEFA.2017.08.010
Abstract: Omega-3 and omega-6 polyunsaturated free fatty acids (PUFA-FFA) are precursors to potent downstream lipid mediators that are regulators of inflammation. We describe the development and validation of a novel and sensitive method for quantification of in idual PUFA-FFA in a dried blood spot using liquid chromatography tandem mass spectrometry (LC-MS/MS). Lipids were extracted from dried blood spot and six in idual PUFA-FFA were quantified by LC-MS/MS using stable isotope dilution analysis with deuterated internal standards. PUFA-FFA concentrations in blood s les from 30 subjects were measured using the new method and compared to the traditional approach of thin layer chromatography followed by gas chromatography with flame ionization detection (TLC-GC). Responses for each PUFA-FFA were linear throughout a range of concentrations expected in clinical s les. Intra-day and inter-day variations for all PUFA-FFA were ≤ 16%. The concentrations of all PUFA-FFA measured by LC-MS/MS were positively correlated with measures of the same PUFA-FFA obtained by a traditional TLC-GC method. This novel method for the quantification of PUFA-FFA extracted from dried blood is sensitive and precise, and accurately measures levels of biologically important PUFA-FFA in blood.
Publisher: American Chemical Society (ACS)
Date: 05-10-2010
DOI: 10.1021/JF103045T
Abstract: The presence of glycosides of smoke-derived volatile phenols in smoke-affected grapes and the resulting wines of Chardonnay and Cabernet Sauvignon was investigated with the aid of high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). All volatile phenols studied (phenol, p-, m-, and o-cresols, methylguaiacol, syringol, and methylsyringol) could be detected as glycosylated metabolites in smoke-affected grapes in a similar fashion to that previously reported for guaiacol. These phenolic glycosides were found in smoke-affected grapes and wines at significantly elevated levels compared to those in non-smoked control grapes and wines. The extraction of these glycosides from grapes into wine was estimated to be 78% for Chardonnay and 67% for Cabernet Sauvignon. After acid hydrolysis, a large proportion of these phenolic glycosides in grapes (50%) and wine (92%) disappeared but the concentrations of volatile phenols determined by gas chromatography-mass spectrometry (GC-MS) were lower than expected. In the case of wine, the majority of the glycosides of phenol, cresols, guaiacol, and methylguaiacol were decomposed upon acid hydrolysis without releasing their respective aglycones, while syringol and methylsyringol were more effectively released.
Publisher: American Chemical Society (ACS)
Date: 18-06-2021
Publisher: American Chemical Society (ACS)
Date: 22-03-2012
DOI: 10.1021/JF300054H
Abstract: Formation of wine thiol precursors is a dynamic process, which can be influenced by vineyard and winery processing operations. With the aim of increasing thiol precursor concentrations, a study of the effects of storing machine-harvested Sauvignon blanc grapes prior to crushing and pressing was undertaken on a commercial scale. 3-Mercaptohexan-1-ol (3-MH) precursors, 2-S-glutathionylcaftaric acid (grape reaction product, GRP), glutathione (GSH) and a number of C6 compounds were assessed at several time points during the experiment. The concentration of the cysteine precursor to 3-MH doubled within 8 h and tripled after 30 h while the GSH and cysteinylglycine precursors increased in concentration roughly 1.5 times. (E)-2-Hexenal and GSH levels decreased as thiol precursors, GRP and C6 alcohols increased during storage. Principal component analysis revealed that precursors contributed to most of the variation within the s les over the storage period, with additional influence, primarily from GSH and GRP, as well as (E)-2-hexenal and (Z)-3-hexen-1-ol. Early storage time points were associated with higher concentrations of GSH and some unsaturated C6 compounds while longer storage times were most closely associated with higher thiol precursor and GRP concentrations. This study provides a detailed overview of interactions related to thiol precursor formation on a commercial scale and highlights the ability to manipulate precursor concentrations prior to grape crushing.
Publisher: MDPI AG
Date: 10-04-2019
DOI: 10.3390/MOLECULES24071404
Abstract: This study investigated compositional changes in red wines resulting from wine alcohol removal by reverse osmosis-vaporative perstraction (RO-EP) and provides insight into the physical and chemical changes in reduced alcohol wine (RAW). Trial 1 involved RO-EP treatment of three wines that were analyzed pre-treatment, post-treatment, and post-treatment with alcohol adjustment (i.e., addition of ethanol to achieve the original alcohol content). Trial 2 involved partial dealcoholization of two wines and analysis of s les collected during RO-EP treatment, i.e., wine in, wine out, retentate, permeate (pre- and post-EP treatment) and strip water. Wine color was analyzed by spectrophotometric methods, while other compositional changes were determined by WineScan, high performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC–MS) analyses. In general, RAWs were slightly more concentrated than pre-treatment wines, which resulted in greater color intensity and increased phenolics and organic acids. However, partial dealcoholization resulted in lower concentrations of some fermentation volatiles, particularly ethyl esters, which may reflect ester hydrolysis following ethanol removal.
Publisher: Universite de Bordeaux
Date: 08-10-2021
DOI: 10.20870/OENO-ONE.2021.55.4.4805
Abstract: Understanding how wine compositional traits can be related to sensory profiles is an important and ongoing challenge. Enhancing knowledge in this area could assist producers to select practices that deliver wines of the desired style and sensory specifications. This work reports the use of spectrofluorometry in conjunction with chemometrics for prediction, correlation, and classification based on sensory descriptors obtained using a rate-all-that-apply sensory assessment of Cabernet-Sauvignon wines (n = 26). Sensory results were first subjected to agglomerative hierarchical cluster analysis, which separated the wines into five clusters represented by different sensory profiles. The clusters were modelled in conjunction with excitation-emission matrix (EEM) data from fluorescence measurements using extreme gradient boosting discriminant analysis. This machine learning technique was able to classify the wines into the pre-defined sensory clusters with 100 % accuracy. Parallel factor analysis of the EEMs identified four main fluorophore components that were tentatively assigned as catechins, phenolic aldehydes, anthocyanins, and resveratrol (C1, C2, C3, and C4, respectively). Association of these four components with different sensory descriptors was possible through multiple factor analysis, with C1 relating to ‘dark fruits’ and ‘savoury’, C2 with ‘barnyard’, C3 with ‘cooked vegetables’ and ‘vanilla/chocolate’, and C4 with ‘barnyard’ and a lack of C1 descriptors. Partial least squares regression modelling was undertaken with EEM data and sensory results, with a model for perceived astringency being able to predict the panel scores with 68.1 % accuracy. These encouraging outcomes pave the way for further studies that relate sensory traits to fluorescence data and move research closer to the ultimate goal of predicting wine sensory expression from a small number of compositional factors.
Publisher: American Chemical Society (ACS)
Date: 28-12-2013
DOI: 10.1021/JF305025J
Abstract: Bushfires occur frequently in the vicinity of grape growing regions, resulting in smoke drifting over the vineyards. Wine made from smoked grapes is often downgraded or unfit for sale due to negative sensory characters. To manage or avoid the risk of producing smoke-affected wine, a diagnostic assay was developed for assessing the extent of smoke exposure in grapes and the resulting wines. The method relies on the quantitation of the glycosidic grape metabolites that are formed from major volatile phenols present in smoke. Using HPLC-MS/MS with APCI, a quantitation method for phenolic glycosides as smoke marker compounds was developed and validated. The method was confirmed to be of sufficient sensitivity and reliability to use as a diagnostic assay. On the basis of phenolic glycoside concentrations, grapes or wine can be assessed as smoke exposed or not, and the relative intensity of smoke exposure can be determined.
Publisher: American Chemical Society (ACS)
Date: 15-03-2017
Abstract: Fermentation-derived volatile sulfur compounds (VSCs) are undesirable in wine and are often remediated in a process known as copper fining. In the present study, the addition of Cu(II) to model and real wine systems containing hydrogen sulfide (H
Publisher: American Chemical Society (ACS)
Date: 11-05-2016
Abstract: Sulfidic off-odors arising during wine production are frequently removed by Cu(II) fining. In part 1 of this study ( 10.1021/acs.jafc.6b00641 ), the reaction of H2S and thiols with Cu(II) was examined however, the interaction of iron and copper is also known to play an important synergistic role in mediating non-enzymatic wine oxidation. The interaction of these two metals in the oxidation of H2S and thiols (cysteine, 3-sulfanylhexan-1-ol, and 6-sulfanylhexan-1-ol) was therefore examined under wine-like conditions. H2S and thiols (300 μM) were reacted with Fe(III) (100 or 200 μM) alone and in combination with Cu(II) (25 or 50 μM), and concentrations of H2S and thiols, oxygen, and acetaldehyde were monitored over time. H2S and thiols were shown to be slowly oxidized in the presence of Fe(III) alone and were not bound to Fe(III) under model wine conditions. However, Cu(II) added to model wine containing Fe(III) was quickly reduced by H2S and thiols to form Cu(I) complexes, which then rapidly reduced Fe(III) to Fe(II). Oxidation of Fe(II) in the presence of oxygen regenerated Fe(III) and completed the iron redox cycle. In addition, sulfur-derived oxidation products were observed, and the formation of organic polysulfanes was demonstrated.
Publisher: Elsevier BV
Date: 03-2011
Publisher: American Chemical Society (ACS)
Date: 11-05-2016
Abstract: Sulfidic off-odors as a result of hydrogen sulfide (H2S) and low-molecular-weight thiols are commonly encountered in wine production. These odors are usually removed by the process of Cu(II) fining, a process that remains poorly understood. The present study aims to elucidate the underlying mechanisms by which Cu(II) interacts with H2S and thiol compounds (RSH) under wine-like conditions. Copper complex formation was monitored along with H2S, thiol, oxygen, and acetaldehyde concentrations after the addition of Cu(II) (50 or 100 μM) to air-saturated model wine solutions containing H2S, cysteine, 6-sulfanylhexan-1-ol, or 3-sulfanylhexan-1-ol (300 μM each). The presence of H2S and thiols in excess to Cu(II) led to the rapid formation of ∼1.4:1 H2S/Cu and ∼2:1 thiol/Cu complexes, resulting in the oxidation of H2S and thiols and reduction of Cu(II) to Cu(I), which reacted with oxygen. H2S was observed to initially oxidize rather than form insoluble copper sulfide. The proposed reaction mechanisms provide insight into the extent to which H2S can be selectively removed in the presence of thiols in wine.
Publisher: MDPI AG
Date: 14-10-2019
DOI: 10.3390/FOODS8100491
Abstract: Warmer growing seasons, variations to grape ripening dynamics, and stylistic changes have contributed to increased wine alcohol levels, which can negatively impact sensory properties. As a consequence, winemakers have sought technological innovations to produce reduced alcohol wine (RAW). The sensory methodology used by industry to optimize the ethanol content of RAW is known as ‘alcohol sweetspotting’. However, to date, there is no scientific evidence to support the alcohol sweetspot phenomenon, and the sensory methodology used for alcohol sweetspotting has not been validated. In this study, different methods of presenting wine s les (i.e., ordered vs. randomized, and linear vs. circular) were employed to determine to what extent presentation order influences the outcome of alcohol sweetspotting trials. Two different approaches to statistical analysis of sensory data, i.e., chi-square goodness of fit vs. one proportion tests, were also evaluated. Statistical analyses confirmed alcohol sweetspots were apparent in some sweetspot determination trials, but outcomes were not reproducible in replicate determinations (either by panel or by in idual panelists). Analysis of data using the one proportion test improved the likelihood of identifying statistically significant differences between RAWs, but variation in in iduals’ sensitivity to differences in sensory properties following ethanol removal prevented validation of the alcohol sweetspot phenomenon based on the wines studied.
Publisher: American Chemical Society (ACS)
Date: 27-04-2018
Abstract: Five co-located clones of Sauvignon blanc grapes were fermented under controlled conditions at laboratory-scale to investigate the impact of yeast strain, commercial enzyme, or nutrient addition on the concentrations of enantiomers of 3-sulfanylhexan-1-ol (3-SH) and 3-sulfanylhexyl acetate (3-SHA) in resulting wines. The relationship of these enantiomers with the odorless 3-SH precursors present in diastereomeric forms in grape juice was also examined. Possible variations may have existed due to clone type, not only for the diastereomers of 3-SH precursors in juices but also for the enantiomers of 3-SH and 3-SHA in the resulting wines, although there was no obvious stereochemical relationship between precursors and free thiols. From a flavor enhancement perspective, the use of a commercial enzyme in the juice significantly enhanced 3-SH production for some clones. In contrast, less impact on the production of 3-SH and 3-SHA was seen as a result of yeast strain and nutrient regardless of clone type.
Publisher: MDPI AG
Date: 10-09-2020
DOI: 10.3390/FOODS9091270
Abstract: Low color stability of Rubired food and beverage coloring negatively impacts color yield during production and storage while also limiting the use of this type of food colorant in applications where color stability is a key requirement. This study investigated the impact on color stability of using flash détente (FD) for Rubired color extraction in comparison to a conventional must heating (CMH) extraction process, in conjunction with the use of commercial seed tannin, acetaldehyde, or acid to lower the pH. Rubired concentrate color was evaluated under accelerated aging conditions at 50, 60, and 70 °C, over zero, three, six, and nine days for the different treatments. FD concentrate had lower color stability, with a half-life of 203.3 h and activation energy of 59.2 kJ/mol at 50 °C compared to the CMH concentrate with 233.9 h and 65.2 kJ/mol. FD concentrate generated less 5-hydroxymethylfurfural (5-HMF) during accelerated aging regardless of treatment. Acetaldehyde, low pH, and the combination of these two treatments increased red color stability as well as violet and brown color, whereas seed tannin had no effect. Low pH treatments increased 5-HMF formation and browning, which was detrimental to concentrate quality. Although promising in terms of color stabilization, implementation of these treatments will require development of solutions to mitigate the production of 5-HMF.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.WASMAN.2017.11.011
Abstract: Grapes are one of the most cultivated fruits worldwide, with one third of total production used in winemaking. Both red and white winemaking processes result in substantial quantities of solid organic waste, such as grape marc (pomace) and stalks, which requires suitable disposal. Grape marc accounts for approximately 10-30% of the mass of grapes crushed and contains unfermented sugars, alcohol, polyphenols, tannins, pigments, and other valuable products. Being a natural plant product rich in lignocellulosic compounds, grape marc is also a promising feedstock for renewable energy production. However, despite grape marc having such potential, advanced technologies to exploit this have not been widely adopted in wineries and allied industries. This review covers opportunities beyond traditional composting and animal feed, and examines value-added uses via the extraction of useful components from grape marc, as well as thermochemical and biological treatments for energy recovery, fuel or beverage alcohol production, and specialty novel products and applications such as biosurfactants and environmental remediation. New advances in relevant technology for each of these processes are discussed, and future directions proposed at both in idual producer and regional facility scales, including advanced processing techniques for integrated ethanol production followed by bioenergy generation from the spent marc.
Publisher: American Chemical Society (ACS)
Date: 16-08-2010
DOI: 10.1021/JF102008R
Abstract: Volatile sulfur compounds can be formed at various stages during wine production and storage, and some may impart unpleasant "reduced" aromas to wine when present at sensorially significant concentrations. Quantitative data are necessary to understand factors that influence the formation of volatile sulfur compounds, but their analysis is not a trivial undertaking. A rapid and selective method for determining 10 volatile sulfur-containing aroma compounds in wine that have been linked to "off-odors" has been developed. The method utilizes static headspace injection and cool-on-column gas chromatography coupled with sulfur chemiluminescence detection (GC-SCD). Validation demonstrated that the method is accurate, precise, robust, and sensitive, with limits of quantitation around 1 microg/L or better, which is below the aroma detection thresholds for the analytes. Importantly, the method does not form artifacts, such as disulfides, during s le preparation or analysis. To study the contribution of volatile sulfur compounds, the GC-SCD method was applied to 68 commercial wines that had reductive sensory evaluations. The analytes implicated as contributors to reductive characters were hydrogen sulfide, methanethiol, and dimethyl sulfide, whereas carbon disulfide played an uncertain role.
Publisher: American Chemical Society (ACS)
Date: 06-01-2009
DOI: 10.1021/JF802799W
Abstract: The identification of 4-S-glutathionyl-4-methylpentan-2-one (glut-4-MMP) by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) experiments in a Sauvignon Blanc juice extract is described. Synthesis of an authentic reference compound enabled confirmation of the presence of glut-4-MMP in a Sauvignon Blanc juice for the first time. The juice extract was obtained by batch-wise percolation of 6 L of juice through a sintered glass funnel packed with C18 sorbent, followed by further purification using low-pressure chromatography on C18. Analysis of the juice extract revealed a chromatographic peak with the same retention time and mass spectrum as the synthetic reference compound, and spiking experiments verified the findings. The presence of glut-4-MMP in grape juice may be related to the biosynthesis of the relevant S-cysteinyl conjugate and, subsequently, to the formation of aroma-active 4-mercapto-4-methylpentan-2-one (4-MMP). This compound has a very low reported sensory threshold (3 ng/L) in wine and is partially responsible for the aromas that are important to the quality and style of some wine varieties.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.PLEFA.2018.08.001
Abstract: Oxylipins are biologically important lipid mediators that are derived enzymatically from polyunsaturated fatty acids (PUFA) and have a major role in regulating inflammatory processes. The currently available methods for measuring oxylipins from human biological s les have limitations, which restricts their use in large studies. We have developed a novel method for measuring 21 oxylipins from dried blood spot (DBS) using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and stable isotope dilution analysis. Our new method is reproducible and precise and enables the high throughput analysis and quantitation of bioactive oxylipins in small volumes of blood. In the future, this new method can be readily applied to measure oxylipins in large studies. Abstract Oxylipins are downstream lipid mediators enzymatically-produced from polyunsaturated fatty acids (PUFA) that are implicated as the biological effectors of these fatty acids. Recently reported methods for the quantitation of oxylipins require complex extraction procedures. In this study, we report the development and validation of a novel system for the quantitation of 21 in idual oxylipins from a dried blood spot (DBS) using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and stable isotope dilution analysis. Linearity and precision of the method were determined and the stabilities of the 12 most abundant oxylipins were tested during 2 months of storage at room temperature, after being spiked into blood and prepared as DBS on PUFAcoat™ paper. Responses were linear across the concentration range analysed for all oxylipins (r
Publisher: MDPI AG
Date: 29-09-2022
Abstract: The sessile plant has developed mechanisms to survive the “rough and tumble” of its natural surroundings, aided by its evolved innate immune system. Precise perception and rapid response to stress stimuli confer a fitness edge to the plant against its competitors, guaranteeing greater chances of survival and productivity. Plants can “eavesdrop” on volatile chemical cues from their stressed neighbours and have adapted to use these airborne signals to prepare for impending danger without having to experience the actual stress themselves. The role of volatile organic compounds (VOCs) in plant–plant communication has gained significant attention over the past decade, particularly with regard to the potential of VOCs to prime non-stressed plants for more robust defence responses to future stress challenges. The ecological relevance of such interactions under various environmental stresses has been much debated, and there is a nascent understanding of the mechanisms involved. This review discusses the significance of VOC-mediated inter-plant interactions under both biotic and abiotic stresses and highlights the potential to manipulate outcomes in agricultural systems for sustainable crop protection via enhanced defence. The need to integrate physiological, biochemical, and molecular approaches in understanding the underlying mechanisms and signalling pathways involved in volatile signalling is emphasised.
Publisher: Elsevier BV
Date: 11-2017
Publisher: MDPI AG
Date: 28-06-2023
Abstract: The volatile-mediated interplay between stressed and non-stressed plants has been described in many studies involving both biotic and abiotic stresses as a one-way channel. However, very little is known about the molecular basis and mechanisms by which volatile organic compounds (VOCs) mediate plant communication between drought-stressed ‘emitter’ plants and non-stressed ‘receiver’ neighbours for the defence against impending stress challenges. Aiming to address this in grapevine, this study investigated the effect of two-way VOC exchange between stressed and non-stressed Vitis vinifera L. cv. Shiraz during drought and recovery using four treatments: isolated well-watered (WW) vines, isolated drought-stressed (DS) vines, and co-located DS ‘emitter’ and WW ‘receiver’ vines in a growth room. The results obtained from solid-phase microextraction (SPME) gas chromatography mass spectrometry (GC-MS) analysis showed a synchronised decline in α-pinene concentration in the co-located treatment vines and higher isoprene levels in the DS emitters compared to the isolated DS vines. Targeted gene expression analysis further identified the over-expression of a key gene, allene oxide synthase (AOS), in the jasmonic acid (JA) biosynthesis pathway during peak drought in the DS emitter. Transcript expression of chorismate synthase (CHORS) and α-pinene synthase (VvPNaPin1) showed similar trends in the DS emitter. The results suggest that isoprene and α-pinene may be interplant signalling molecules used by grapevine during drought. To the best of our knowledge, this is the first report of a bi-directional interaction in grapevine between the emitters and receivers under drought stress mediated by the JA and terpenoid biosynthesis pathways.
Publisher: Springer Science and Business Media LLC
Date: 15-03-2016
Publisher: American Chemical Society (ACS)
Date: 07-07-2014
DOI: 10.1021/JF501945S
Abstract: Chardonnay is one of the oldest and most widely distributed wine grape cultivars and is of commercial importance for the world's wine-producing nations. It is an extremely flexible variety that has adapted to different regions with varied weather and soil characteristics. Somewhat uniquely among white wines, Chardonnay lends itself to a wide variety of production styles, which can be tailored to the target market. Techniques such as skin maceration, barrel and stainless steel fermentation, use of selected or indigenous yeasts, malolactic fermentation, and aging in barrels with or without lees are all applicable and lead to different compositional outcomes. A number of research papers have been published with a view to understanding Chardonnay composition and quality as well as the impact of different enological techniques on the final product. This review summarizes current knowledge, explaining the influence of viticultural and production techniques on aroma composition, and poses directions for further research into Chardonnay wines.
Publisher: MDPI AG
Date: 26-12-2018
DOI: 10.3390/MOLECULES24010073
Abstract: The colour of red wine is largely determined by the concentration of anthocyanins that are extracted from grape skins during fermentation. Because colour is a key parameter in determining the overall quality of the finished product, understanding the effect of processing variables on anthocyanin extraction is critical for producing a red wine with the desired sensorial characteristics. In this study, the effect of convective conditions (natural and forced) on the mass transfer properties of malvidin-3-glucoside (M3G) from pre-fermentative grape solids was explored at various liquid phase conditions representing stages of fermentation. A mathematical model that separates solid and liquid phase mass transfer parameters was applied to experimental extraction curves, and in all cases, provided a coefficient of determination exceeding 0.97. Calculated mass transfer coefficients indicated that under forced convective conditions, the extraction process was controlled by internal diffusion whereas under natural convection, both internal diffusion and liquid-phase mass transfer were relevant in determining the overall extraction rate. Predictive simulations of M3G extraction during active fermentation were accomplished by incorporating the current results with a previously developed fermentation model, providing insight into the effect of a dynamic liquid phase on anthocyanin extraction.
Publisher: MDPI AG
Date: 17-07-2021
DOI: 10.3390/MOLECULES26144334
Abstract: In a global context where trading of wines involves considerable economic value, the requirement to guarantee wine authenticity can never be underestimated. With the ever-increasing advancements in analytical platforms, research into spectroscopic methods is thriving as they offer a powerful tool for rapid wine authentication. In particular, spectroscopic techniques have been identified as a user-friendly and economical alternative to traditional analyses involving more complex instrumentation that may not readily be deployable in an industry setting. Chemometrics plays an indispensable role in the interpretation and modelling of spectral data and is frequently used in conjunction with spectroscopy for s le classification. Considering the variety of available techniques under the banner of spectroscopy, this review aims to provide an update on the most popular spectroscopic approaches and chemometric data analysis procedures that are applicable to wine authentication.
Publisher: American Chemical Society (ACS)
Date: 20-04-2023
Publisher: American Society for Enology and Viticulture
Date: 11-07-2016
Publisher: American Chemical Society (ACS)
Date: 04-2008
DOI: 10.1021/JF073478W
Abstract: A rapid technique for the isolation of polymeric polyphenols from red wine has been developed and validated. A copolymer reversed-phase SPE cartridge was utilized in conjunction with predominantly organic eluents to provide three phenolic fractions from red wine without the need for s le pretreatment. The first fraction contained the bulk of the monomeric and oligomeric phenolic material, while the second and third fractions contained the polymeric polyphenolic compounds, as determined by HPLC analysis. The two polymeric polyphenolic fractions differed in their solubility and extent of pigmentation, and the differences appeared to be related to wine age. This method contrasted with other available fractionation techniques because the interfering, nonpolymeric material can be removed in a single wash fraction, while the polymeric material is separated into two distinct fractions based on their erse physicochemical properties. It is anticipated that the rapid access to discrete polymeric fractions afforded by this method will be of benefit in furthering the understanding of red wine polymeric polyphenols.
Publisher: Hindawi Limited
Date: 18-04-2023
DOI: 10.1155/2023/2428791
Abstract: Rootstock can significantly alter the concentration of methoxypyrazines (MPs) in the bunch stem (rachis) of Vitis vinifera L. cv. Cabernet Sauvignon and Shiraz, which has implications for winemaking and wine style. The distribution of MPs across the rachis is an important consideration, but such information was not available. This study aimed to address this research question by comparing MP concentrations in different rachis components throughout grape maturation and in the absence of ambient light. Shiraz and Cabernet Sauvignon bunches were s led throughout development, segmented into four components (peduncle, top rachis, bottom rachis, and pedicel), and 3-isobutyl-2-methoxypyrazine (IBMP) was quantified in each. For both cultivars, IBMP showed a negative correlation with grape maturity, with concentrations in pedicel at harvest being significantly higher than other rachis components. Additionally, light exclusion significantly increased IBMP concentrations in all rachis segments. The concentration of IBMP varied significantly between different rachis components. The greatest concentrations were measured in the pedicel, which also contributed the largest proportion among the components to total rachis by weight. Due to elevated IBMP concentrations in rachis and the difficulties in excluding matter other than grape from a fermentor, the presence of pedicel during fermentation could produce Shiraz and Cabernet Sauvignon wines with higher concentrations of MPs, thereby potentially increasing vegetal sensory characteristics.
Publisher: American Society for Enology and Viticulture
Date: 23-03-2017
Publisher: Elsevier BV
Date: 2021
Publisher: American Chemical Society
Date: 2012
Publisher: American Chemical Society
Date: 2012
Publisher: American Chemical Society (ACS)
Date: 21-01-2010
DOI: 10.1021/JF903732P
Abstract: Fermentation of grapes that had been exposed to bushfire smoke can potentially yield unpalatable, smoke-affected wine. Guaiacol and its glucoconjugate were previously found in smoke-affected grapes at an elevated concentration. To find and identify further guaiacol conjugates in smoke-affected grapes, a stable isotope feeding experiment combined with extensive HPLC-MS and MS/MS investigations was carried out. Leaves and berries of a potted grapevine were placed in contact with an aqueous mixture of d(0)- and d(3)-guaiacol for 1-2 days and collected 5 weeks later. Screening for potential guaiacol conjugates in the leaves and berries was facilitated by monitoring the unique mass spectrometric signature of an isotopic doublet separated by 3 Da. Seven different conjugates were detected in leaves and berries and were tentatively identified as mono- and diglycosides of guaiacol. Quantitative analysis demonstrated that the guaiacol conjugates were translocated between leaves and berries to a very limited extent and were also present as low-level natural compounds of untreated leaves and berries. The same guaiacol conjugates were also found at a considerably elevated concentration in leaves and berries obtained from grapevines exposed to bushfire smoke.
Publisher: MDPI AG
Date: 24-03-2023
Abstract: Uniform grape maturity can be sought by producers to minimise underripe and/or overripe proportions of fruit and limit any undesirable effects on wine quality. Considering that grape heterogeneity is a multifaceted phenomenon, a composite index summarising overall grape heterogeneity was developed to benefit vineyard management and harvest date decisions. A grape heterogeneity index (GHI) was constructed by aggregating the sum of absolute residuals multiplied by the range of values from measurements of total soluble solids, pH, fresh weight, total tannins, absorbance at 520 nm (red colour), 3-isobutyl-2-methoxypyrazine, and malic acid. Management of grape heterogeneity was also studied, using Cabernet Sauvignon grapes grown under four viticultural regimes (normal/low crop load, full/deficit irrigation) during the 2019/2020 and 2020/2021 seasons. Comparisons of GHI scores showed grape variability decreased throughout ripening in both vintages, then significantly increased at the harvest time point in 2020, but plateaued on s le dates nearing the harvest date in 2021. Irrigation and crop load had no effect on grape heterogeneity by the time of harvest in both vintages. Larger vine yield, leaf area index, and pruning weight significantly increased GHI score early in ripening, but no significant relationship was found at the time of harvest. Differences in the Ravaz index, normalised difference vegetation index, and soil electrical conductivity did not significantly change the GHI score.
Publisher: Hindawi Limited
Date: 30-04-2015
DOI: 10.1111/AJGW.12142
Publisher: American Chemical Society (ACS)
Date: 04-05-2016
Abstract: Two rosé wines, representing a tropical and a fruity/floral style, were chosen from a previous study for further exploration by aroma extract dilution analysis (AEDA) and quantitative analysis. Volatiles were extracted using either liquid-liquid extraction (LLE) followed by solvent-assisted flavor evaporation (SAFE) or a recently developed dynamic headspace (HS) s ling method utilizing solid-phase extraction (SPE) cartridges. AEDA was conducted using gas chromatography-mass spectrometry/olfactometry (GC-MS/O) and a total of 51 aroma compounds with a flavor dilution (FD) factor ≥3 were detected. Quantitative analysis of 92 volatiles was undertaken in both wines for calculation of odor activity values. The fruity and floral wine style was mostly driven by 2-phenylethanol, β-damascenone, and a range of esters, whereas 3-SHA and several volatile acids were seen as essential for the tropical style. When extraction methods were compared, HS-SPE was as efficient as SAFE for extracting most esters and higher alcohols, which were associated with fruity and floral characters, but it was difficult to capture volatiles with greater polarity or higher boiling point that may still be important to perceived wine aroma.
Publisher: American Chemical Society (ACS)
Date: 04-2011
DOI: 10.1021/JF200116Q
Abstract: A method has been developed for determining 3-mercaptohexan-1-ol (3-MH) in wine and grape juice using gas chromatography with conventional electron ionization (EI) mass spectrometry. The limit of quantitation of 40 ng/L was achieved with excellent precision using stable isotope dilution analysis (SIDA) combined with headspace solid-phase microextraction (SPME) of derivatized 3-MH. This method was used in combination with HPLC-MS/MS analysis of the in idual diastereomers of 3-S-cysteinylhexan-1-ol (Cys-3-MH) and 3-S-glutathionylhexan-1-ol (Glut-3-MH), which are known precursors of the volatile thiol 3-MH. Commercial and small-lot winemaking trials were evaluated to determine the concentrations of precursors and free 3-MH at various stages of grape processing and winemaking. Five Sauvignon blanc clones were also assessed for precursors and free thiol during ripening, revealing the presence of 3-MH in the unfermented juices and a stark increase in precursor concentrations in the latter stage of ripening. Additionally, differences due to s le freezing and mode of juice preparation were revealed for the precursors, and a set of commercially available wines was analyzed to investigate the amounts of precursors and free 3-MH in Sauvignon blanc and other white wine varieties. There was seemingly no relationship between precursor concentrations in juice and 3-MH concentrations in wine. This was somewhat understandable, because the formation of precursors appears to be a dynamic process affected by a multitude of factors, beginning with grape ripening and continuing during vinification.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Informa UK Limited
Date: 16-02-2019
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.FOODCHEM.2016.02.042
Abstract: Rosé wine aromas range from fruity and floral, to more developed, savoury characters. Lighter than red wines, rosé wines tend to match well with Asian cuisines, yet little is known about the factors driving desirability of rosé wines in emerging markets such as China. This study involved Chinese wine professionals participating in blind rosé wine tastings comprising 23 rosé wines from Australia, China and France in three major cities in China. According to the sensory results, a link between the preference, quality and expected retail price of the wines was observed, and assessors preferred wines with prominent red fruit, floral, confectionery and honey characters, and without developed attributes or too much sweetness. Basic wine chemical parameters and 47 volatile compounds, including 5 potent thiols, were determined. Correlations between chemical components, sensory attributes and preference/quality/expected price were visualised by network analysis, revealing relationships that are worthy of further investigation.
Publisher: Elsevier BV
Date: 02-2023
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.FOODCHEM.2018.02.120
Abstract: The current study determined the applicability of sequential and orthogonalised-partial least squares (SO-PLS) regression to relate Cabernet Sauvignon grape chemical composition to the sensory perception of the corresponding wines. Grape s les (n = 25) were harvested at a similar maturity and vinified identically in 2013. Twelve measures using various (bio)chemical methods were made on grapes. Wines were evaluated using descriptive analysis with a trained panel (n = 10) for sensory profiling. Data was analysed globally using SO-PLS for the entire sensory profiles (SO-PLS2), as well as for single sensory attributes (SO-PLS1). SO-PLS1 models were superior in validated explained variances than SO-PLS2. SO-PLS provided a structured approach in the selection of predictor chemical data sets that best contributed to the correlation of important sensory attributes. This new approach presents great potential for application in other explorative metabolomics studies of food and beverages to address factors such as quality and regional influences.
Publisher: Elsevier BV
Date: 11-2004
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.FOODRES.2016.08.006
Abstract: This study investigated the effect of different contexts on consumers' mood, product-evoked emotions, liking and willingness to pay for wine. Three consumer trials (n=114, 115, and 120) examined 3 different s le sets of 4 Australian commercial Shiraz wines. Each s le set was comprised of a high, medium-high, medium-low and low quality wine as designated by an expert panel. Wine consumers evaluated the same set of wines in the three different contexts, ranging from a highly-controlled laboratory setting to more realistic restaurant and at-home settings. Results showed that high quality wines were liked more and elicited more intense emotions of positive valence compared to wines of lower quality. Context effects were observed on emotions, but not on liking, indicating that although emotions and liking are correlated, the measurement of emotions can deliver additional information over liking. Tasting wine in the restaurant context evoked more intense positive emotions compared to the home and laboratory contexts. Participants' mood before tasting the wines had a strong influence on consecutive product-evoked emotion ratings, but only weak influence on liking ratings. Furthermore, a strong relationship between wine-evoked emotions and willingness to pay was observed, showing that if a wine-evoked more intense emotion of positive valence e.g., contented, enthusiastic, happy, optimistic and passionate participants were willing to pay significantly more for a bottle. Additionally, the absence of negative emotions, even if typically evoked to a very weak extent, is a requirement for an increased willingness to pay. This study indicates it is worthwhile to consider context and emotions in wine testing and marketing.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.FOODRES.2018.12.044
Abstract: Anthocyanins are polyphenolic compounds present in grapes that are responsible for the initial colour of red wine and their incorporation into derived pigments leads to long term colour stability. The ability to predict the effect of process variables, either controlled by winemakers or that naturally change throughout fermentation, on the extraction of anthocyanins is vital to producing red wine of high quality. A 2
Publisher: American Chemical Society (ACS)
Date: 13-12-2022
Publisher: Elsevier BV
Date: 11-2021
Publisher: Wiley
Date: 08-2022
Abstract: Color is one of the most distinctive qualities of red wine. Despite new knowledge in the field of pigment identification, copigmentation, and oxidation being forthcoming, there is still a large gap between the fundamental research and practical winemaking outcomes. A state‐of‐art review from these two aspects is, therefore, necessary. This review first introduces updated knowledge about the primary pigments in wine, with emphasis on their physicochemical properties. Then, the mechanisms of copigmentation and oxidation are elucidated in detail, along with their relative contributions to wine color. Finally, the practical effects of copigmentation and micro‐oxygenation (MOX) in winemaking are summarized and discussed. In general, wine coloration is ultimately determined by the anthocyanin flavylium cation, which is greatly influenced by wine pH. In young red wine, grape‐derived anthocyanins and nonanthocyanin polyphenols (as copigments) are the foundation for wine coloration. During aging and storage, anthocyanin derivatives are formed via various chemical reactions, where moderate oxidation plays a vital role, whereas copigmentation constantly decreases. The essence of wine color evolution relates to the changes of physicochemical properties of primary pigments in wine, where the hydration equilibrium gradually diminishes. In practice, the effects of copigment addition and MOX during real vinification can be viewed as somewhat controversial, considering that many studies showed different effects on wine color and pigment concentration. Universal features can be summarized but some phenomena still remain unclear and deserve further exploration.
Publisher: Elsevier BV
Date: 05-2020
Publisher: American Chemical Society (ACS)
Date: 17-09-2018
Abstract: Polymeric sorbents are frequently used in wine, either as solid phase extraction materials for isolation of analytes or as sorptive materials for removal of undesirable compounds (amelioration). Six new polymeric sorbents were produced thermally or in a microwave from various ratios of methacrylic acid, acrylic acid, and 4-vinylbenzoic acid as hydrophilic monomers, together with ethylene glycol dimethacrylate as cross-linker, using different porogen solvents. The relationship between physicochemical properties (pore size, surface area, and polarity) of the sorbents and their sorption properties for compounds in wine was investigated and compared to four commercially available sorbents. With some similarities to their commercial counterparts depending on hydrophobic and hydrophilic characteristics, the six new sorbents showed specificity toward different groups of compounds (e.g., volatiles and phenolics) and could be applied for targeted purposes. The results provide insight into the selection and utilization of new polymeric materials for extraction of components from wine.
Publisher: Informa UK Limited
Date: 10-2019
Publisher: Elsevier BV
Date: 05-2016
Publisher: Elsevier BV
Date: 12-2002
Publisher: American Chemical Society (ACS)
Date: 20-04-2022
Abstract: Ramsey rootstock has previously been implicated in an approximate 8-fold increase of 3-isobutyl-2-methoxypyrazine (IBMP) levels in the rachis (grape bunch stem) of
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.FOODCHEM.2019.125698
Abstract: Pre-fermentative juice substitution with water or early harvest wine has the potential to produce lower alcohol wines without critically modifying colour or tannin properties and only marginally changing volatile and sensory profiles. Whether this approach is suited to producing lower alcohol wines in the absence of excessive grape ripeness remained to be determined. The current study extends on pre-fermentative approaches to alcohol management under milder grape ripening conditions and builds on an existing study with McLaren Vale Cabernet Sauvignon fruit, allowing for a direct comparison under two distinct vintage conditions. Given its importance to Australia, Shiraz was also included and underwent the same consecutive harvest and juice substitution treatments. Cultivar-dependent implications on wine chemical properties were apparent and declines in wine colour and tannin were particularly evident in Shiraz wines, although impacts on overall wine quality and sensory parameters were minor when adjusting musts within the limit of 13.5 °Baumé.
Publisher: American Chemical Society (ACS)
Date: 15-01-2010
DOI: 10.1021/JF9037198
Abstract: Synthesis of the putative wine thiol precursor 3-S-glutathionylhexan-1-ol (Glut-3-MH) has been undertaken to provide pure reference materials for the development of HPLC-MS/MS methods for precursor quantitation in grape juice and wine, and for use in fermentation experiments. Labeled thiol conjugates were also prepared for use as internal standards. Purification and fermentation of a single diastereomer of Glut-3-MH with VIN13 (CSL1) yielded not only the (R)-enantiomer of the wine impact odorant 3-mercaptohexan-1-ol (3-MH) but also the cysteine conjugate intermediate as a single (R)-diastereomer, as determined by HPLC-MS/MS. Chiral GC-MS was used to quantify the total amount of (R)-3-MH released from the ferments, resulting in a molar conversion yield of the glutathione conjugate of about 3%. Enzymatic degradation of the single (R)-Glut-3-MH diastereomer with a gamma-glutamyltranspeptidase confirmed the stereochemical relationship to the related cysteine conjugate. This is the first demonstration that Glut-3-MH can liberate 3-MH under model fermentation conditions, where the cysteine conjugate is also formed in the process. This furthers our understanding of the nature of wine thiol precursors and opens avenues for additional studies into formation and interchange of wine thiols and their precursors.
Publisher: American Chemical Society (ACS)
Date: 16-03-2005
DOI: 10.1021/OL050236D
Abstract: [reaction: see text] A short total synthesis of the putative structure of the marine natural product tridachiahydropyrone as a single enantiomer is described. Novel steps include a cuprate addition and cyclization to form a cyclohexanone ring and formation of the bicyclic pyrone with P(2)O(5) on Celite. The spectroscopic data obtained for compound 1 do not match those reported for tridachiahydropyrone therefore, revision of the assigned natural product structure is warranted.
Publisher: American Chemical Society (ACS)
Date: 26-09-2011
DOI: 10.1021/JF202543Z
Abstract: Precursors to varietal wine thiols are a key area of grape and wine research. Several such precursors, in the form of odorless conjugates, have been closely studied in recent years. A new conjugate has now been identified as 3-S-cysteinylglycinehexan-1-ol (Cysgly-3-MH), being the dipeptide intermediate between cysteine and glutathione precursors of tropical thiol 3-mercaptohexan-1-ol (3-MH). Authentic Cysgly-3-MH was produced via enzymatic transformation of the glutathione conjugate and used to verify the presence of both diastereomers of Cysgly-3-MH in Sauvignon blanc juice extracts. Cysgly-3-MH was added into our HPLC-MS/MS precursor method, and the validated method was used to quantify this new analyte in a selection of Sauvignon blanc juice extracts. Cysgly-3-MH was found in the highest concentrations (10-28.5 μg/L combined diastereomer total) in extracts from berries that had been machine-harvested and transported for 800 km in 12 h. This dipeptide conjugate was much less abundant than the glutathione and cysteine conjugates in the s les studied. On the basis of the results, the new cysteinylglycine conjugate of 3-MH seemingly has a short existence as an intermediate precursor, which may explain why it has not been identified as a natural juice component until now.
Publisher: American Chemical Society (ACS)
Date: 06-01-2005
DOI: 10.1021/OL0478178
Abstract: [reaction: see text] A novel approach to the formation of the unusual pyrone-containing ring systems as found in polypropionate metabolites from the Tridachia family of marine molluscs has been developed. This approach includes an intramolecular cyclization of a beta-keto acid onto a cyclohexenone ring to afford a fused, bicyclic pyrone.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Hindawi Limited
Date: 02-03-2021
DOI: 10.1111/AJGW.12488
Publisher: American Chemical Society (ACS)
Date: 06-01-2015
DOI: 10.1021/AC503883S
Abstract: Volatile sulfur compounds contribute characteristic aromas to foods and beverages and are widely studied, because of their impact on sensory properties. Certain thiols are particularly important to the aromas of roasted coffee, cooked meat, passion fruit, grapefruit, and guava. These same thiols enhance the aroma profiles of different wine styles, imparting pleasant aromas reminiscent of citrus and tropical fruits (due to 3-mercaptohexan-1-ol, 3-mercaptohexyl acetate, 4-mercapto-4-methylpentan-2-one), roasted coffee (2-furfurylthiol), and struck flint (benzyl mercaptan), at nanogram-per-liter levels. In contrast to the usual gas chromatography (GC) approaches, a simple and unique high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for routine analysis of five wine thiols, using 4,4'-dithiodipyridine (DTDP) as a derivatizing agent and polydeuterated internal standards for maximum accuracy and precision. DTDP reacted rapidly with thiols at wine pH and provided stable derivatives, which were enriched by solid-phase extraction (SPE) prior to analysis by HPLC-MS/MS. All steps were optimized and the method was validated in different wine matrices, with method performance being comparable to a well-optimized but more cumbersome gas chromatography-mass spectrometry (GC-MS) method. A range of commercial wines was analyzed with the new method, revealing the distribution of the five thiols in white, red, rosé, and sparkling wine styles.
Publisher: Elsevier BV
Date: 11-2021
Publisher: American Chemical Society (ACS)
Date: 29-07-2020
Publisher: MDPI AG
Date: 29-04-2015
Publisher: Hindawi Limited
Date: 09-02-2023
DOI: 10.1155/2023/8041096
Abstract: Background and Aims. An OIV resolution provides guidelines on using glutathione as a prefermentation additive when the amount of yeast assimilable nitrogen (YAN) of a juice or must is adequate, to avoid the metabolism of glutathione by the yeast. The effect of YAN concentration on glutathione metabolism by yeast had not been determined. This study explored whether nitrogen management could be used to control glutathione consumption during fermentation. Methods and Results. An HPLC-UV method was developed to quantify reduced L-glutathione (GSH) and oxidised glutathione (GSSG) and used to monitor yeast GSH metabolism during alcoholic fermentation with two yeast strains (AWRI 1688 and AWRI 2861). The addition of GSH had no impact on the fermentation rate of the chemically defined medium, even in a limited YAN environment however, a decrease in glutathione concentration occurred regardless of YAN concentration. The effect of GSH on volatile sulfur compound formation was yeast strain-dependent. Conclusions. Increasing the YAN status of a chemically defined medium led to a decrease in GSH consumption during fermentation, but the loss of GSH could not be prevented entirely, even with a low initial GSH concentration and high initial YAN. Significance of the Study. In the presence of higher concentrations of GSH during fermentation, there is a risk of forming undesirable fermentative sulfur compounds that are not mitigated through nitrogen supplementation. Thus, it seems unlikely that an argument could be made for the inclusion of GSH in relevant food standards codes as a wine additive especially if a lack of GSH metabolism was a criterion.
Publisher: American Chemical Society (ACS)
Date: 23-02-2012
DOI: 10.1021/JF204499H
Abstract: Preliminary investigations revealed that the proximity of Eucalyptus trees to grapevines can directly influence the concentration of the aroma compound 1,8-cineole present in the corresponding red wines. For two different vineyards, the closer the grapevines were to the trees, the greater was the amount of 1,8-cineole in the wines elaborated from those grapes. This led us to carry out further studies to quantify the levels of 1,8-cineole found in grape berries, leaves, and stems at set distances from Eucalyptus trees over multiple vintages. Generally, the highest concentration of 1,8-cineole was found in the grapevine leaves, followed by grape stems and then grapes. In each s le type, we observed greater concentrations of 1,8-cineole in s les closer to the trees. Various fermentation treatments carried out with Shiraz grapes showed that matter other than grapes (MOG, e.g., Eucalyptus or grape leaves) could contribute significant amounts of 1,8-cineole to the finished wines. These studies confirmed that vineyard position and winemaking conditions can determine the 1,8-cineole concentration in red wine. The fermentation study also showed for the first time that the concentration of rotundone in red wine can be strongly influenced by grapevine leaves and stems in the ferment.
Publisher: American Chemical Society
Date: 2011
Publisher: Elsevier BV
Date: 12-2021
Publisher: Hindawi Limited
Date: 06-12-2021
DOI: 10.1111/AJGW.12469
Publisher: Elsevier BV
Date: 10-2019
Publisher: American Chemical Society (ACS)
Date: 05-10-2018
Abstract: On the basis of the chemistry of wine and the co-occurrence of 3-sulfanylhexan-1-ol (3-SH) and acetaldehyde, we investigated the existence of 2-methyl-4-propyl-1,3-oxathiane (1) and identified the presence of a single detectable geometric isomer, cis-1, in wines for the first time. A stable isotope dilution assay (SIDA) using headspace-solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was developed and validated, and used to quantitate cis-1 in a survey of wines, revealing a range from undetectable (limit of detection = 2.6 ng/L) to 460 ng/L. The odor detection threshold of 1 (using a standard comprising 85% cis-1 and 15% trans-1) in neutral white wine was determined to be 7.1 μg/L. Despite cis-1 not appearing above the determined sensory threshold in the studied wines, the findings demonstrated the presence of a new volatile sulfur compound with a strong correlation to 3-SH concentration ( r = 0.72), showing that cis-1 has potential implications for the fate of the important wine aroma compound 3-SH.
Publisher: MDPI AG
Date: 19-04-2023
DOI: 10.3390/FERMENTATION9040394
Abstract: Digital control systems are well established in many industries and could find application in the wine sector. Of critical importance to red wine quality, the efficient and targeted extraction of polyphenols from red grape solids during alcoholic fermentation could be a focus for automation. Smart technologies such as model predictive control (MPC) or fuzzy logic appear ideal for application in a complex process such as wine polyphenol extraction, but require mathematical models that accurately describe the system. The aim of this study was to derive and validate a model describing the extraction of catechin (a representative polyphenol) from red grape solids under simulated fermentation conditions. The impact of ethanol, fermentable sugar, and temperature on extraction rate was determined, with factor conditions chosen to emulate those present in industry practice. A first-order approach was used to generate an extraction model based on mass conservation that incorporated temperature and sugar dependency. Coefficients of determination (R2) for all test scenarios exceeded 0.94, indicating a good fit to the experimental data. Sensitivity analysis for the extraction rate and internal cross-validation showed the model to be robust, with a small standard error in cross-validation (SECV) of 0.11 and a high residual predictive deviation (RPD) of 17.68. The model that was developed is well suited to digital technologies where low computational overheads are desirable, and industrial application scenarios are presented for future implementation of the work.
Publisher: MDPI AG
Date: 27-08-2018
DOI: 10.3390/MOLECULES23092159
Abstract: Extraction of grape components is a key consideration for red winemaking. The impact of changing process variables on mass transfer properties of anthocyanins from fresh pre-fermentative red grape solids under forced convective conditions was explored using the dominant red grape anthocyanin, malvidin-3-glucoside (M3G) as a model solute. A two level full factorial design was implemented to investigate effects of temperature, sugar and ethanol on mass transfer properties. Factor levels were chosen to simulate conditions found at various points during the maceration and fermentation steps of the red winemaking process. A rigorous mathematical model was developed and applied to experimental extraction curves, allowing the separation of mass transport properties in liquid and solid phases in a wine-like system, for the first time. In all cases, the coefficient of determination exceeded 0.92, indicating good agreement between experimental and mathematically-solved M3G concentrations. For the conditions studied, internal mass transfer was found to limit M3G extraction and changes to the liquid phase composition and temperature influence the distribution constant. Surface response models of mass transfer parameters were developed to allow future simulations of fermentation scenarios aimed at maximising the extraction potential of M3G.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.FOODCHEM.2017.10.024
Abstract: A changing climate has led to winegrapes being harvested with increased sugar levels and at greater risk of berry shrivel. A suggested easy-to-adopt strategy to manage the associated rising wine alcohol levels is the pre-fermentative substitution of juice with either "green harvest wine" or water. Our study investigates the effects of this approach on Vitis vinifera L. cv. Cabernet Sauvignon wine quality attributes. Wines were also made from fruit collected at consecutive earlier harvest time points to produce wines comparable in alcohol to the substituted wines. Tannin concentrations and colour did not change significantly in the wines with modified alcohol content even at higher juice substitution rates. Differences in polysaccharide and tannin composition indicated variability in extraction dynamics according to substitution rate and type of blending component. In scenarios where berry shrivel is inevitable, the incorporation of water in particular offers much promise as part of a strategy to manage wine alcohol content.
Publisher: American Chemical Society (ACS)
Date: 13-06-2018
Abstract: 3-Isobutyl-2-methoxypyrazine (IBMP) is a potent odorant present in grapes and wines that is reminiscent of green capsicum. Suprathreshold concentrations can lead to obvious vegetative characters and suppress desirable fruity aroma nuances in wines, but options to manage IBMP concentrations are limited. This work investigated pre- and postfermentation addition of a putative imprinted magnetic polymer (PIMP) as a remedial treatment for elevated concentrations of IBMP in Cabernet Sauvignon grape must in comparison to nonimprinted magnetic polymer (NIMP) and to a commercially available polylactic acid (PLA) based film added postfermentation. Chemical and sensory analyses of wines showed that PIMP treatments were more effective than PLA film for decreasing "fresh green" aroma nuances without negatively impacting overall aroma profiles and that postfermentation addition of a magnetic polymer removed up to 74% of the initial IBMP concentration compared to 18% for PLA. Prefermentation addition of magnetic polymers removed 20-30% less IBMP compared to that of postfermentation addition but also had less of an effect on other wine volatiles and color parameters.
Publisher: American Chemical Society (ACS)
Date: 28-02-2012
DOI: 10.1021/JF2040548
Abstract: Guaiacol and 4-methylguaiacol are well-known as contributors to the flavor of wines made from smoke-affected grapes, but there are other volatile phenols commonly found in smoke from forest fires that are also potentially important. The relationships between the concentration of a range of volatile phenols and their glycoconjugates with the sensory characteristics of wines and model wines were investigated. Modeling of the attribute ratings from a sensory descriptive analysis of smoke-affected wines with their chemical composition indicated the concentrations of guaiacol, o-cresol, m-cresol, and p-cresol were related to smoky attributes. The best-estimate odor thresholds of these compounds were determined in red wine, together with the flavor threshold of guaiacol. Guaiacol β-D-glucoside and m-cresol β-D-glucoside in model wine were found to give rise to a smoky/ashy flavor in-mouth, and the respective free volatiles were released. The study indicated that a combination of volatile phenols and their glycosides produces an undesirable smoke flavor in affected wines. The observation of flavor generation from nonvolatile glycoconjugates in-mouth has potentially important implications.
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.FOODRES.2018.10.086
Abstract: Ganoderma lucidum (GL) is a woody mushroom that has been widely used for many centuries in traditional Chinese medicine. Its bioactive-compounds are believed to promote longevity and prevent diseases in humans. With the close proximity of emerging Asian markets, Australian winemakers are beginning to adopt consumer-centric wine product development as a strategy to generate wines with profiles that meet the specific demands of these consumers. This cross-cultural study recruited 412 wine consumers (Chinese, Vietnamese and Australian) to participate in a survey to understand wine consumers' potential acceptance and self-reported intent towards new wine products produced with GL extracts and the relationship of their responses with wine neophobicity across cultures. Findings revealed that all consumer groups accepted the notion that GL wine products would be worth tasting and they would try them at social events, with Vietnamese consumers being particularly interested. Using the wine neophobia scale (WNS), three segments containing wine neophiles (n = 110), neutrals (n = 190) and wine neophobes (n = 112) were identified. The results revealed that Australian and Chinese participants were significantly more wine neophilic, compared to Vietnamese. As expected, neophiles were more prepared to taste and purchase GL wine products compared to neophobes across all three countries, although no gender differences were observed. The study provides the wine industry insights about consumers' attitudes towards a new GL wine product targeted to Australian and Asian markets that could help develop new niche wine categories and enhance consumers' satisfaction.
Publisher: American Chemical Society (ACS)
Date: 15-01-2010
DOI: 10.1021/JF903720W
Abstract: A method has been developed and validated for the analysis of the in idual diastereomers of 3-S-cysteinylhexan-1-ol (Cys-3-MH) and 3-S-glutathionylhexan-1-ol (Glut-3-MH) extracted from grape juice and wine. The method uses stable isotope dilution analysis (SIDA) combined with solid-phase extraction (SPE) and reversed-phase high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for quantitation. These compounds have been considered as potential precursors to the important wine odorant 3-mercaptohexan-1-ol (3-MH). This constitutes the first analytical method where (1) Glut-3-MH has been accurately quantified in grape juice and wine and (2) the in idual Cys- and Glut-3-MH diastereomers were separated and quantified by a single HPLC-MS/MS method. The use of deuterium-labeled internal standards has resulted in an accurate and precise method that can achieve quantitation limits of <0.5 microg/L for the in idual Cys- and Glut-3-MH diastereomers in grape juice and white wine. The method has been applied to the determination of 3-MH precursor diastereomers in various white juice and wine s les. Overall, Glut-3-MH was always more abundant than Cys-3-MH in the juices and wines examined, regardless of grape variety. Stereochemically, (S)-Glut-3-MH generally dominated over the (R)-diastereomer in the juices and wines, but there was not such a marked difference between the distribution of Cys-3-MH diastereomers. These results have important implications for understanding the formation of wine flavor, and the application of this method will allow further exploration of precursors to the varietal thiol 3-MH.
Publisher: Hindawi Limited
Date: 22-12-2020
DOI: 10.1111/AJGW.12474
Publisher: American Chemical Society (ACS)
Date: 27-09-2012
DOI: 10.1021/JF301571Q
Publisher: MDPI AG
Date: 10-05-2020
DOI: 10.3390/MOLECULES25092245
Abstract: Changes to regulations by Food Standards Australia New Zealand have permitted the adjustment of must sugar levels with the addition of water in order to ensure a sound fermentation progress as well as mitigating excessive wine–alcohol levels. This study assessed the implications for Shiraz wine quality following a pre-fermentative must dilution (changing liquid-to-solid ratios), in comparison to juice substitution with water (constant liquid-to-solid ratios) that has previously been deemed a promising way to adjust wine–alcohol levels. While working within the legal limit of water addition to grape must, the effects of both approaches on wine quality parameters and sensory characteristics were rather similar, and of negligible nature. However, different implications between substitution and dilution appeared to be driven by grape maturity, and dilution was found to have a greater impact than substitution on some parameters at higher water implementation rates. In line with previous observations, longer hang-time followed by alcohol adjustments via pre-fermentation water addition were of limited merit compared to simply picking grapes earlier. This work provided further knowledge that supports informed decision making regarding the recently permitted approach of using water during winemaking.
Publisher: MDPI AG
Date: 31-01-2017
Publisher: American Chemical Society (ACS)
Date: 12-12-2018
Abstract: Diorganopolysulfanes can be generated when hydrogen sulfide (H
Publisher: Elsevier BV
Date: 03-2023
Publisher: MDPI AG
Date: 09-02-2023
Abstract: Generations of sensors have been developed for predicting food sensory profiles to circumvent the use of a human sensory panel, but a technology that can rapidly predict a suite of sensory attributes from one spectral measurement remains unavailable. Using spectra from grape extracts, this novel study aimed to address this challenge by exploring the use of a machine learning algorithm, extreme gradient boosting (XGBoost), to predict twenty-two wine sensory attribute scores from five sensory stimuli: aroma, colour, taste, flavour, and mouthfeel. Two datasets were obtained from absorbance-transmission and fluorescence excitation-emission matrix (A-TEEM) spectroscopy with different fusion methods: variable-level data fusion of absorbance and fluorescence spectral fingerprints, and feature-level data fusion of A-TEEM and CIELAB datasets. The results for externally validated models showed slightly better performance using only A-TEEM data, predicting five out of twenty-two wine sensory attributes with R2 values above 0.7 and fifteen with R2 values above 0.5. Considering the complex biotransformation involved in processing grapes to wine, the ability to predict sensory properties based on underlying chemical composition in this way suggests that the approach could be more broadly applicable to the agri-food sector and other transformed foodstuffs to predict a product’s sensory characteristics from raw material spectral attributes.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.FOODCHEM.2018.03.118
Abstract: This study extends previous work on Cabernet Sauvignon wines of lowered alcohol concentrations produced by pre-fermentatively substituting proportions of juice from an overripe crop with "green harvest wine" or water to adjust initial sugar concentrations. Resulting wines were assessed for their volatile compositions and sensory characteristics to evaluate the suitability of this winemaking approach to managing wine alcohol concentrations in warm viticulture regions. Wines from water or green harvest wine substitution were also compared to wines of similar alcohol content produced from earlier harvested grapes. Implementation of water substitution in particular resulted in minor alterations of wine volatile composition compared to the control, and positive aroma and flavour characteristics were preserved. However, overripe sensory attributes such as 'hotness' and 'port wine' were conserved whereas they were absent in wines of similar alcohol level made from earlier harvested grapes, thereby emphasising the relevance of grape (over)maturity when producing lower alcohol wines.
Publisher: MDPI AG
Date: 09-02-2011
Abstract: Over the last two decades, improvements in perinatology have led to increased survival rates of preterm infants. A large number of studies and meta-analyses have investigated of preterm infants and/or the influence of developmental care. However, the combined influence of the most frequent risk factors and developmental care on the long-term somatic, motor, and cognitive outcome of preterm infants remains unclear. This retrospective, single-center cohort study includes 256 children treated in a tertiary neonatal intensive care unit in Rostock, Germany, between 2008 and 2013. Follow-up examinations (somatic, psychomotor, and mental development) were performed at (corrected) 24 months using Bayley Scales of Infant Development II (BSID-II). Developmental care was carried out according to the legal framework and national guidelines (physiotherapy and/or early education). Bronchopulmonary dysplasia (BPD) and an exclusive formula feeding showed a 2.8–4.6-fold higher risk (95% Confidence Interval: Mental Developmental Index 1.73–7.58 Psychomotor Developmental Index 1.44–14.54 body length 1.20–6.41) for developmental deficits (mental and psychomotor developmental index body length). Developmental care after discharge according to national guidelines did not prevent this. Since this is a retrospective pilot study, no recommendations can be made based on this analysis. Therefore, future research should evaluate whether standard developmental care should be extended by tailored measures depending on in idual risk factors.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.FOODCHEM.2019.05.126
Abstract: Sauvignon blanc grape s les (n = 21) from across a single Geographical Indication of South Australia were analysed for thiol precursors and amino acids, and fermented in an identical laboratory-scale fermentation trial to investigate the intraregional pattern of varietal thiols in the wines. Precursors and thiols exhibited obvious intraregional ersity, and notably, stronger correlations were observed between a number of amino acids and thiol precursors (especially with glutamic acid, r ≤ -0.73) rather than free thiols. Additionally, pre-fermentation freezing (-20 °C, 1 month) was applied to five selected fresh grape s les and their juices, followed by identical fermentation. In comparison to wines from fresh grapes or frozen juices, significant elevation of varietal thiols (up to 10-fold) occurred in the wines derived from frozen grapes, with parallel increases of precursors (up to 19-fold) in juices from frozen berries. These novel results may lead to new strategies for thiol enhancement during winemaking.
Publisher: Elsevier BV
Date: 10-2020
Publisher: MDPI AG
Date: 27-06-2023
DOI: 10.3390/MOLECULES28135016
Abstract: Despite Xinomavro (Vitis vinifera L.) being a well-known noble red grape variety of northern Greece, little is known about its ‘‘bouquet’’ typicity. Volatile compounds of Xinomavro wines produced using a common vinification protocol were analyzed by gas chromatography–mass spectrometry and sensory descriptive analysis was carried out with a trained panel. Wines were characterized by the presence of fatty acids, ethyl and acetate esters, and alcohols, with contributions from terpenes and a volatile phenol. The most active aroma compounds were determined to be 3-methylbutyl acetate, β-damascenone, ethyl esters of octanoic and hexanoic acids, and eugenol. Those compounds positively correlated with fruity and spicy odor descriptors, with the wines being mostly characterized by five typical aroma terms: strawberry, berry fruit, spices, tomato, and green bell pepper. Partial least squares regression (PLSR) analysis was used to visualize relationship between the orthonasal sensory attributes and the volatile aroma compounds with calculated OAVs 1. Key aroma-active volatiles in the wines were identified using GC-MS/olfactometry, providing a list of 40 compounds, among which 13 presented a modified detection frequency 70%. This study is the first of its kind and provided strong indications regarding the aroma compounds defining the sensory characteristics of Xinomavro wines.
Publisher: American Society for Enology and Viticulture
Date: 15-12-2018
Publisher: American Chemical Society (ACS)
Date: 04-01-2011
DOI: 10.1021/JF1038212
Abstract: A new method has been developed for the quantitation of 1,8-cineole in red and white wines using headspace solid-phase microextraction (SPME) combined with stable isotope dilution analysis (SIDA) and gas chromatography-mass spectrometry (GC-MS). An extensive survey of Australian wines (44 white and 146 red) highlighted that only red wines contained significant amounts of 1,8-cineole (up to 20 μg/L). Hydrolytic studies with limonene and α-terpineol, putative precursors to 1,8-cineole, showed a very low conversion into 1,8-cineole (< 0.6%) over a 2 year period, which does not account for the difference between white and red wines. 1,8-Cineole was chemically stable in model wine solution over 2 years, and absorption from a Shiraz wine by bottle closures was most evident for a synthetic closure only (14% absorption after 1 year). Two commercial ferments at two different locations were monitored daily to investigate the evolution of 1,8-cineole throughout fermentation. Both ferments showed daily increases in 1,8-cineole concentration while in contact with grape solids, but this accumulation ceased immediately after pressing. This observation is consistent with the extraction of 1,8-cineole into the ferment from the solid portions of the grape berries.
Publisher: American Chemical Society (ACS)
Date: 13-05-2014
DOI: 10.1021/JF405731V
Abstract: The key aroma compounds of premium Australian Shiraz wines from the warm Barossa Valley and cooler Margaret River regions were characterized. GC-Olfactometry was conducted to determine the most important volatile compounds, which were then quantitated. The wine from the Barossa Valley had higher concentrations of ethyl propanoate, dimethyl sulfide (DMS), and oak-derived compounds, whereas the Margaret River wine contained above threshold concentrations of the 'cheesy' compounds 2- and 3-methylbutanoic acid, as well as rotundone, the 'pepper'-smelling compound. The aromas were reconstituted by combining 44 aroma compounds, and sensory descriptive analysis was used to investigate the importance of the omission of several compounds, including DMS, rotundone, fatty acids, and β-damascenone, and the influence of nonvolatiles was also assessed. The study showed that the aroma of the Shiraz wines could be reconstituted in both cases, with the changes in the nonvolatile fraction having a large influence.
Publisher: Elsevier BV
Date: 09-0100
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 2022
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/CH03139
Abstract: The cyclization products from the photolysis of 3-arylamino-4-ethoxycarbonyl-2-heteroarylisoxazol-5(2H)-ones are interpreted as arising from intramolecular cyclization of carbenes. The mode of cyclization appears to be controlled by hydrogen bonding of the 3-NH group with either the 2-heteroaryl group or the 4-ethoxycarbonyl group.
Publisher: Hindawi Limited
Date: 08-2008
Publisher: Springer Science and Business Media LLC
Date: 13-04-2020
Publisher: American Society for Enology and Viticulture
Date: 22-09-2017
Publisher: MDPI AG
Date: 05-07-2019
DOI: 10.3390/MOLECULES24132472
Abstract: Certain volatile thiols are some of the most potent odour-active molecules that are found in nature. Thiols play significant roles in the aroma qualities of a range of foods and beverages, including wine, with extremely low odour detection thresholds (nanogram per litre range). A fundamental understanding of their formation, fate, and impact essentially depends on the development of suitable analytical methods. The analysis of volatile thiols in foods and beverages is a challenging task when considering (1) the complexity of food and beverage matrices and (2) that thiols are highly reactive, low molecular-weight volatiles that are generally present at trace to ultra-trace concentrations. For the past three decades, the analytical evaluation of volatile thiols has been intensively performed in various foods and beverages, and many novel techniques related to derivatisation, isolation, separation, and detection have been developed, particularly by wine researchers. This review aims to provide an up-to-date overview of the major analytical methodologies that are proposed for potent volatile thiol analysis in wine, foods, and other beverages. The analytical challenges for thiol analysis in foods and beverages are outlined, and the main analytical methods and recent advances in methodology are summarised and evaluated for their strengths and limitations. The key analytical aspects reviewed include derivatisation and s le preparation techniques, chromatographic separation, mass spectrometric detection, matrix effects, and quantitative analysis. In addition, future perspectives on volatile thiol research are also suggested.
Publisher: American Chemical Society (ACS)
Date: 02-01-2019
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 04-2020
Publisher: American Chemical Society (ACS)
Date: 30-03-2011
DOI: 10.1021/JF200119Z
Abstract: The effects of different processing treatments on thiol precursor concentrations have been investigated through studies involving transportation of machine-harvested Sauvignon blanc fruit and assessment of different applications of antioxidants, along with juice preparation and enzyme inhibition experiments. The influence these trials had on 3-S-cysteinylhexan-1-ol (Cys-3-MH) and 3-S-glutathionylhexan-1-ol (Glut-3-MH) concentrations in juices is discussed. Very interesting findings included the large increase in precursor concentrations after transportation, particularly for Cys-3-MH, and the limited formation of Glut-3-MH when grape proteins were precipitated during processing. The various results provided information about the ability to modulate precursor concentrations depending on the processing technique employed. Additionally, a conjugated aldehyde, which is the obvious missing link between the reaction of (E)-2-hexenal and glutathione in the formation of Glut-3-MH, has been tentatively identified for the first time. Deuterium-labeled 3-S-glutathionylhexanal (Glut-3-MHAl) was produced through the addition of labeled (E)-2-hexenal to grapes, followed by grape crushing, and detected in the juice by HPLC-MS/MS, along with the corresponding labeled Glut-3-MH.
Publisher: Springer Science and Business Media LLC
Date: 12-09-2019
Publisher: MDPI AG
Date: 17-12-2019
DOI: 10.3390/FOODS8120691
Abstract: Understanding the sensory attributes that explain the typicity of Australian Cabernet Sauvignon wines is essential for increasing value and growth of Australia’s reputation as a fine wine producer. Content analysis of 2598 web-based wine reviews from well-known wine writers, including tasting notes and scores, was used to gather information about the regional profiles of Australian Cabernet Sauvignon wines and to create selection criteria for further wine studies. In addition, a wine expert panel evaluated 84 commercial Cabernet Sauvignon wines from Coonawarra, Margaret River, Yarra Valley and Bordeaux, using freely chosen descriptions and overall quality scores. Using content analysis software, a sensory lexicon of descriptor categories was built and frequencies of each category for each region were computed. Distinction between the sensory profiles of the regions was achieved by correspondence analysis (CA) using online review and expert panellist data. Wine quality scores obtained from reviews and experts were converted into Australian wine show medal categories. CA of assigned medal and descriptor frequencies revealed the sensory attributes that appeared to drive medal-winning wines. Multiple factor analysis of frequencies from the reviews and expert panellists indicated agreement about descriptors that were associated with wines of low and high quality, with greater alignment at the lower end of the wine quality assessment scale.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.ACA.2017.10.031
Abstract: A number of polyfunctional thiols are well-recognised as some of the most potent aroma compounds in nature and have been identified in various foods, and beverages such as wine. These potent character impact compounds are present at nanogram-per-litre levels and are particularly challenging to measure. Where present, enantiomeric forms having different odour qualities further complicate the analysis. In this work, a chiral high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method using stable isotope dilution analysis (SIDA) has been developed and validated for the in idual enantiomers of 3-sulfanylhexan-1-ol (3-SH, 1) and its O-acetate, 3-sulfanylhexyl acetate (3-SHA, 2), in wine after extraction as their 4-thiopyridine derivatives. Authentic derivatised thiols were first synthesised and used for chiral column screening and method development with polysaccharide-based HPLC phases. Validation of the method using a Lux Amylose-1 column for quantification of the enantiomers of 1 and 2 gave linear calibrations, and excellent figures for accuracy (recovery: 90%-111%, Z-score: -1.8-1.9), precision (RSD
Publisher: MDPI AG
Date: 20-02-2020
DOI: 10.3390/FOODS9020224
Abstract: This study explored wine consumers’ preferences towards a novel Australian Shiraz wine product containing Ganoderma lucidum (GL). Wine consumers (n = 124) were asked to complete a questionnaire and participate in a blind tasting of six GL wine products (differing in the amount and timing of GL extract additions). Based on in idual liking scores for each GL wine product that was tasted, four hedonic clusters C1 (n = 44, preferred control and low levels of GL additions), C2 (n = 28, preferred control only), C3 (n = 26, generally preferred all GL additions) and C4 (n = 26, preferred 1 g/L additions and 4 g/L post-fermentation) were identified. Sensory attributes of the GL wine products were also profiled with rate-all-that-apply (n = 65) and the 31 sensory attributes that significantly differentiated the wines underwent principal component analysis with the hedonic clusters overlaid to explain consumers’ preferences. There was a clear separation between hedonic clusters. Sensory attributes and volatile flavor compounds that significantly differentiated the wines were subjected to partial least squares regression, which indicated the important positive drivers of liking among the hedonic clusters. Pepper and jammy aroma, 3-methylbutanoic acid (linked to fruity notes) and non-fruit aftertaste positively drove C2′s preference, whereas spice flavor and hexanoic acid (known for leafy and woody descriptors) drove C3′s liking. There were no positive drivers for C1′s liking but bitter taste, cooked vegetable, and toasty aromas drove this cluster’ dislike. C4 preferred brown appearance, tobacco aroma, and jammy and cooked vegetable flavors. These findings provide the wine industry with deeper insights into consumers’ liking towards new GL wine products targeted at the Australasian market.
Publisher: Wiley
Date: 23-11-2018
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.FOODCHEM.2015.09.111
Abstract: The appeal of rosé wine is attributable to its sensory profiles and underlying chemical composition, which are determined by viticultural and oenological inputs. This study provided the first insight into the sensory attributes and volatile profiles of Australian rosé wines. An HS-SPME-GC-MS method and a recently developed HPLC-MS/MS method were used to quantify 51 volatile compounds, including 4 potent sulfur compounds, in 26 commercial rosé wines. Descriptive analysis on all wines was undertaken and the sensory results were correlated with quantitative chemical data to explore relationships between wine composition and sensory profiles. Based on odour activity values, esters were prominent aroma volatiles, and β-damascenone, 3-methylbutyl acetate, ethyl hexanoate and 3-MHA were deemed to be important, in accord with other studies. Wines were described with terms ranging from developed, spicy and savoury to fresh green, citrus, tropical fruit, floral and confectionery.
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/CH16296
Abstract: Wine is an amazingly complex natural product that requires dedicated scientists to resolve many of its mysteries. Traditional synthetic organic chemistry and modern analytical techniques are powerful tools at the disposal of wine chemists who tackle the complexities of wine in order to improve scientific understanding and provide practical solutions to industry. Part of this quest for knowledge relates to maintaining or improving wine quality, which underpins consumer acceptance and links to the competitiveness of wineries in a global market. Wine aroma is an important aspect of wine quality and garners much attention from researchers. Grape-derived aroma compounds are one area of particular importance owing to their distinctiveness and ability to impart ‘varietal aromas’ to wines. Varietal thiols imparting tropical and citrus notes that are characteristic of wines such as Sauvignon Blanc have emerged, along with their grape-derived precursors, as an area of interest over the past two decades. These compounds have also caught our attention and we have made some important contributions to this field, including identifying new precursors, developing novel analytical methods, and conducting studies that provide unique insights into the biochemical transformations occurring in grape berries and juice, and during fermentation.
Publisher: MDPI AG
Date: 11-2019
DOI: 10.3390/FOODS8110538
Abstract: Novel Shiraz red wine products enriched with Ganoderma lucidum (GL) extract, a traditional Asian medicinal mushroom, were developed and characterized. GL extract was added at different levels prior to and after primary fermentation to investigate its impact on the juice fermentation kinetics, and the chemical composition and sensory properties of the resulting wines. The fermentation kinetics of red grape juice were not significantly different between ferments. Basic chemical analyses plus headspace solid-phase micro-extraction (HS-SPME), gas chromatography‒mass spectrometry (GC-MS), and a rate-all-that-apply (RATA) (n = 65) sensory panel were used to investigate the influence of GL extract additions on wine composition and sensory characteristics. Of the 54 sensory attributes assessed, 39 significantly differentiated the wines. A clear separation between GL wine treatments was evident with PLS regression, where specific volatiles were correlated with relevant sensory attributes that dominated the wines. These products could be promising for emerging wine markets.
Start Date: 2017
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 2013
End Date: 2015
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2014
End Date: 12-2017
Amount: $2,405,204.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2023
End Date: 04-2026
Amount: $511,205.00
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2018
End Date: 12-2024
Amount: $4,459,672.00
Funder: Australian Research Council
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