Analytical study of aromatic series in sherry wines subjected to biological aging

Enhancing variety aromatic characteristics of Muscat wine through cold maceration with indigenous cryotolerant Metschnikowia pulcherrima Mp0520

Cold maceration (CM) is widely applied in winemaking to improve wine aroma and overall quality. However, more efficient CM techniques for industrial-scale winemaking are still needed. This study examined the impact of CM with indigenous cryotolerant Metschnikowia pulcherrima Mp0520 (Mp-CM) on the Muscat wine aromatic characteristics. The results demonstrated a significant divergence in the types and concentrations of aroma compounds between Mp-CM wine and the control. The Mp-CM wine exhibited a significantly higher terpenes content, resulting in a Muscat wine characterized by terpenes, compared to the control predominated by esters. Additionally, the Mp-CM wine demonstrated elevated levels of α-terpineol and terpinolene, potentially enhancing the varietal aroma stability of Muscat wine. Furthermore, Mp-CM gave Muscat wine a heightened fruity aroma and a more complex aroma. These findings suggested that the Mp-CM utilized in this study offered promising avenues for enhancing the variety aroma characteristics of Muscat wine on large scale winemaking.

Discovering the volatilome fingerprint of selected traditional Cuban wines elaborated with native grapes, tropical fruits, and rice using DHS-TD-GC-MS

Cuban wine is a traditional alcoholic beverage elaborated with a wide variety of raw materials, such as native grapes, tropical fruits, and rice, and different winemaking processes. Research on Cuban wines is almost nonexistent, and therefore, a study of these wines is necessary to improve their quality. Dynamic headspace (DHS)-TD-gas chromatography-mass spectrometry (GC-MS) analysis was carried out to establish the different aroma fingerprints of different Cuban wines. A total of 42 volatile aroma metabolites (VAMs) were identified, including esters, alcohols, aldehydes, acids, volatile phenols, terpenes, and lactones. The odorant activity values (OAV) of each VAM were obtained, and the esters were the most relevant group due to their highest OAV. Ethyl octanoate, hexanoate, and butanoate stand out and are considered key odorants in the aromatic fingerprint. The VAMs were grouped into seven aromatic series. Fruity series showed the highest OAVs due to the contribution of ethyl esters and acetates. Principal component analysis was used to identify the specific parameters most accurately reflecting the differences between the wines. Showing that fruity, spicy, and chemical aromatic series allow distinguishing the wines into three aroma types. These results may provide useful information for the selection of raw materials and optimization of the traditional winemaking processes of Cuban wines. PRACTICAL APPLICATION: This research contributes to knowledge of the aroma and the oenological parameters of traditional and selected Cuban wines (rice wine, tropical fruit wine, and native grape varieties). The establishing of the aroma fingerprint of these wines provides useful information for the industrial development of a quality product that may then be promoted in other areas of the world.

Evolution of Aroma Profiles in Vitis vinifera L. Marselan and Merlot from Grapes to Wines and Difference between Varieties

The fermentation process has a significant impact on the aromatic profile of wines, particularly in relation to the difference in fermentation matrix caused by grape varieties. This study investigates the leaching and evolution patterns of aroma compounds in Vitis vinifera L. Marselan and Merlot during an industrial-scale vinification process, including the stages of cold soak, alcohol fermentation, malolactic fermentation, and one-year bottle storage. The emphasis is on the differences between the two varieties. The results indicated that most alcohols were rapidly leached during the cold soak stage. Certain C6 alcohols, terpenes, and norisoprenoids showed faster leaching rates in 'Marselan', compared to 'Merlot'. Some branched chain fatty-acid esters, such as ethyl 3-methylbutyrate, ethyl 2-methylbutyrate, and ethyl lactate, consistently increased during the fermentation and bottling stages, with faster accumulation observed in 'Marselan'. The study combines the Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) model based on odor activity values to elucidate the accumulation of these ethyl esters during bottle storage, compensating for the reduction in fruity aroma resulting from decreased levels of (E)-β-damascenone. The 'Marselan' wine exhibited a more pronounced floral aroma due to its higher level of linalool, compared to the 'Merlot' wine. The study unveils the distinctive variation patterns of aroma compounds from grapes to wine across grape varieties. This provides a theoretical framework for the precise regulation of wine aroma and flavor, and holds significant production value.

Determination of volatile compounds for the differentiation of PDO fortified wines with different ageing methods as a tool for controlling their authenticity

The aim of this work was to study the differentiating volatile profiles of the Spanish protected designation of origin (PDO) fortified wines obtained by headspace solid phase microextraction in conjunction with gas chromatography-mass spectrometry and powerful chemometric tools, to finally identify the marker volatile compounds most related to fortified wine types. Results revealed a satisfactory discrimination, for the first time, of the different types of PDO fortified wines, involving only a reduced number of volatile compounds selected by chemometrics. Thus, 28 volatile compounds were responsible for the differentiation according to ageing type (biological, oxidative, or mixed) resulting useful markers for the identification of each specific type of fortified wine. Among them, some esters were strongly related to biological ageing, aldehydes and acids to oxidative ageing, and lactones to mixed ageing. These volatile molecules involved in their differentiation could explain the unique organoleptic characteristics or attributes of these PDO fortified wines.

The Fingerprint of Fortified Wines-From the Sui Generis Production Processes to the Distinctive Aroma

The fortified wines that originated in Mediterranean countries have, in common, a high alcohol content to increase their shelf-life during long journeys to northern Europe and the American continent. Nowadays, the world's better-known wines, including Marsala, Madeira, Port, and Sherry, due to their high alcoholic content, sweet taste, and intense aromatic profile, are designated as dessert wines and sometimes served as aperitifs. This review gives an overview of the traditional vinification process, including the microbiota and autochthonous yeast, as well as the regulatory aspects of the main Italian, Portuguese, and Spanish fortified wines. The winemaking process is essential to defining the volatile organic compounds (VOCs) that characterize the aroma of each fortified wine, giving them an organoleptic fingerprint and "terroir" characteristics. The various volatile and odorous compounds found in fortified wines during the oxidative aging are discussed in the last part of this review.

Characterization of aroma compounds and effects of amino acids on the release of esters in Laimao baijiu

BACKGROUND

Laimao baijiu is a typical soy-sauce aroma-type baijiu in China. Amino acids are non-volatile compounds in baijiu and are beneficial to human health. Aroma is one of the important indicators that are used to evaluate the quality of baijiu. The interaction between aroma-active compounds and non-volatile compounds can also affect the release of aroma compounds. In this study, we identified the active-aroma compounds and amino acids in Laimao baijiu by stir bar sorptive extraction (SBSE), gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). The interaction between amino acids and key esters was investigated by sensory analysis and partition coefficients.

RESULTS

A total of 63 aroma compounds and 21 amino acids were identified. Twenty-one esters were identified from them as major aroma-active ester compounds with odor activity values ≥ 1. Finally, sensory analysis revealed that l-alanine had a significant effect on the strength of the aromas of esters, suggesting that low concentrations of amino acids were more likely to promote the release of esters and high concentrations were more likely to inhibit this. The partition coefficient can be a good explanation for this phenomenon.

CONCLUSION

l-Alanine can significantly affect the aroma intensity of key ester aroma compounds in Laimao baijiu, and the effects of different concentrations of amino acids are different. This work shows that amino acids, as non-volatile compounds, have a regulatory effect on the release of aroma compounds in alcoholic beverages, which may provide new technical support for the aroma modulation of alcoholic beverages. © 2022 Society of Chemical Industry.

Saturated Linear Aliphatic γ- and δ-Lactones in Wine: A Review

Saturated linear aliphatic lactones are widespread aroma compounds in wine, linked to stone fruit, dried red fruit, and coconut descriptors. Despite their ubiquity, bioproduction pathways associated with these compounds in wine are unclear, but higher concentrations have been linked to many common vitivinicultural practices, including grape variety, microbiological influence, oak- and bottle-aging, and wine styles such as late harvest, noble rot, and icewine. Development of analytical techniques has enabled increasingly accurate quantification of lactones in wine, shedding more light on their potential origins. This review provides an in-depth summary of the research into linear aliphatic lactones over the past 50 years and provides direction for possible future research to elucidate the biogenesis of these compounds and better estimate their impact on wine aroma.

Adaptive Laboratory Evolution of Yeasts for Aroma Compound Production

Aroma compounds are important in the food and beverage industry, as they contribute to the quality of fermented products. Yeasts produce several aroma compounds during fermentation. In recent decades, production of many aroma compounds by yeasts obtained through adaptive laboratory evolution has become prevalent, due to consumer demand for yeast strains in the industry. This review presents general aspects of yeast, aroma production and adaptive laboratory evolution and focuses on the recent advances of yeast strains obtained by adaptive laboratory evolution to enhance the production of aroma compounds.

Cluster Thinning Improves Aroma Complexity of White Maraština (Vitis vinifera L.) Wines Compared to Defoliation under Mediterranean Climate

Defoliation and cluster thinning are useful canopy management techniques to modulate grapevine carbon distribution and microclimate. Both techniques are directed to achieve the proper balance between fruit and foliage, and to maximize production of well-ripened fruits and quality wines. We performed five canopy treatments on Maraština grapevine grown at a commercial vineyard in the Vrgorac Valley region of Croatia: three different times of basal defoliation, cluster thinning at the veraison, and an untreated control. The effects of the canopy changes on the chemical composition of grapes and wines were studied. The treatments had variable impacts on yield components and basic wine composition. Volatile aroma compounds in produced wines were analyzed using gas chromatography–mass spectrometry coupled with a mass-selective detector. The concentrations of 70 of the 96 individual volatile compounds were significantly influenced by the canopy technique used. The concentrations of 58 of these compounds were different according the timing of defoliation. Cluster thinning at an intensity of 35% produced wines with more terpenes, esters, higher alcohols, other alcohols, volatile phenolic compounds, lactones, and other compounds than other treatments. Among terpenes, cluster thinning increased terpinen-4-ol, linalool, trans-β-farnesen, and geraniol. Odor activity value analysis revealed 16 volatile compounds that contributed to the aroma of cluster-thinned wines.

Chemical and Sensory Profiles of Sauvignon Blanc Wine Following Protein Stabilization Using a Combined Ultrafiltration/Heat/Protease Treatment

Ultrafiltration (UF) was evaluated as a process by which proteins can be selectively removed from white wine as an alternative approach to protein stabilization than traditional bentonite fining. Unfined Sauvignon Blanc wine (50 L) was fractionated by UF and the retentate stabilized either by heat and/or protease treatment or bentonite fining before being recombined with the permeate. The heat stability of recombined wine was significantly improved when retentate was heated following protease (Aspergillopepsin) addition and subsequently stabilized by bentonite treatment. The combined UF/heat/protease treatment removed 59% of protein and reduced the quantity of bentonite needed to achieve protein stability by 72%, relative to bentonite treatment alone. This innovative approach to protein stabilization had no significant impact on wine quality or sensory characteristics, affording industry greater confidence in adopting this technology as a novel approach to achieving protein stability.

Influence of the Dry Yeast Preparation Method on Final Sparkling Wine Characteristics

The effect of preparing the commercial yeast prise de mousse S. cerevisiae IOC 18-2007 on the second fermentation kinetics of a Macabeo white base wine was evaluated. The influence of yeast preparation on the final “Cava” sparkling wines was determined. The medium glucose, peptone, yeast extract (GPY medium), and the characteristic classic pied de cuve procedure were used to prepare the inoculum, which was placed besides a tirage liqueur inside bottles in which a second fermentation took place by the “traditional method”. The fermentation kinetics were similar for the first 60 days regardless of the employed yeast inoculum preparation. In both cases, glucose was exhausted and a few grams of fructose remained on day 30. The ethanol concentration after 60 days was the same in all of the wines. The sparkling wines inoculated with the GPY-grown yeasts showed higher titratable acidity, lower total polysaccharide and protein contents, and greater foamability (HM) and foam stability (HS). Regarding volatile compounds, these wines contained higher esters, fatty acids, higher alcohols, and γ-butyrolactone. Differences in the wine’s visual and flavor attributes were not significant no matter what inoculum was used. However, the aroma score was significantly higher in the wines inoculated with the pied de cuve-prepared yeasts.

A Comparative Study of Yeasts for Rosa roxburghii Wine Fermentation

Wine produced by fermentation of Chestnut rose (Rosa roxburghii) hips, known as cili (Chinese-Mandarin), in Guizhou province, and other places in China is becoming popular but there is limited knowledge of suitable yeast strains for its production. In this study, we first investigated the oenological properties of six commercial S. cerevisiae yeast strains (X16, F33, SH12, GV107, S102, RMS2), one commercial Saccharomyces cerevisiae var. bayanus (S103), one commercial, non-Saccharomyces yeast strain, Torulaspora delbrueckii Prelude, and one indigenous S. cerevisiae strain, CZ, for cili wine fermentation. We measured the key traits of each of the yeast strains, viz., sulfite resistance, flocculation, hydrogen sulfide production capacity, fermentation rate, and yeast growth curves. Subsequently, we measured the resultant wine characteristics, viz., pH, alcohol content, residual sugar, titratable acidity, volatile acidity, ascorbic acid content and headspace volatile compounds. The overall suitability of each yeast type was evaluated using a multi-factor, unweighted, scorecard. On that basis, RMS2 was the most suitable, and closely followed by CZ and X16. This study is the first comparative evaluation of yeasts for cili wine production and provides a preliminary guide for their selection.

Effects of the Irrigation of Chelva Grapevines on the Aroma Composition of Wine

Climate change scenarios are predicting an increase in temperature as well as more scarce and torrential rainfall episodes. Due to this, an imbalance between grape technological and phenolic maturity is being observed, which detrimentally affects the grapes’ composition. In semi-arid areas, irrigation management is a main field practice used to influence grape ripening. The goal of the present study was to investigate the influence of vine irrigation on the aroma composition and sensory characteristics of La Mancha Chelva wines. Volatile compounds were studied by gas chromatography–mass spectrometry (GC/MS). A total of 75 aroma compounds were identified and quantified in Chelva wines elaborated with grapes of irrigated and non-irrigated vines. The results show that the application of irrigation during vine cultivation produced small changes in the concentration of wine volatile compounds. Nevertheless, it increased, in general, the intensity of the attributes of the main aroma sensory profile of the wines. According to the results, the vine irrigation of Chelva cultivated in the La Mancha region can be used as a method to increase the aroma of wines.

Relationships between Shanghai Five Different Home-Brewed Wines Sensory Properties and Their Volatile Composition Assessed by GC-MS

In order to determine the key aroma components of home-brewed wines made from different local grapes in Shanghai. In the work, the identification and quantification of 63 aroma compounds of five home-brewed wines characterized by gas chromatography-mass spectrometry (GC-MS) combined with Headspace Solid-Phase Microextraction (HS-SPME). To study the possible correlation between the sensory attributions and 22 aroma compounds in Odor Activity Value (OAV) > 1 for five home-brewed wines, the Partial Least Squares Regression (PLSR) was a multivariate data analysis performed. Furthermore, to investigate the percentage of contribution of a particular aroma compound to its overall flavor, the relative odor contribution (ROC) and odor activity value of volatiles in home-brewed wines were conducted and performed. According to the comprehensive results, Summer Black Seedless grape (SBSG) and Black Beet grape (BBG) were the most appropriate varieties to be brewed wines for people in Shanghai or around it.

Effects of Girdling and Foliar Fertilization with K on Physicochemical Parameters, Phenolic and Volatile Composition in ‘Hanxiangmi’ Table Grape

Aroma is one of the most important indicators of grape quality. Girdling and foliar fertilization with K (K2O) are common agronomic practices applied to improve berry quality in grape production. However, little is known about its effect on the accumulation and biosynthesis of the entire aromatic profile. Our study was aimed to explore the influences of girdling and foliar fertilization with K (alone or in combination) on the general properties, phenolic composition, volatile free aroma compounds, spatial and temporal expression of terpene-related genes and sensory properties in ‘Hanxiangmi’ table grape. In this study, we found that girdling and foliar fertilization with K (alone or in combination) facilitated fruit enlargement and increased the accumulation of phenolic compounds in skin. The combination treatment of girdling and foliar fertilization with K significantly promoted the concentrations of total soluble solids (TSS) in the pulp and proanthocyanidins in the berry skin, and had a lower titratable acidity (TA) compared to those of the control. In contrast, girdling treatment alone increased the concentrations of titratable acidity. Volatile free aroma composition analysis revealed that the combination treatment increased the volatile compounds and concentrations significantly, most notably in terpenes, such as nerol, citronellol and linalool. Spatial and temporal expression analysis showed that the expression level of VvDXS was significantly correlated with linalool and total terpenes concentrations, as a result of which, we speculated that VvDXS is the candidate gene for the regulation of important grape terpenes. We hope that our results can direct farmers to better apply girdling and foliar fertilization with K in grape production.

Assessment of chemical constitution and aroma properties of kiwi wines obtained from pure and mixed fermentation with Wickerhamomyces anomalus and Saccharomyces cerevisiae

BACKGROUND

To improve the aroma of kiwi wine through the utilization of Wickerhamomyces anomalus, kiwi juice was fermented using a selected W. anomalus strain in pure culture and mixed fermentations with Saccharomyces cerevisiae, which was inoculated simultaneously and sequentially. The physicochemical indices, volatile compounds and aroma properties of the kiwi wines were assessed.

RESULTS

The study suggested that the ethanol, color indices and organic acids of the wines were closely related to the method of inoculation. Compared with the pure S. cerevisiae fermentation, the mixed fermentations produced more varieties and concentrations of volatiles. The sequential fermentations increased the concentrations of esters and terpenes, improving the flower and sweet fruit notes of the wines. The simultaneous inoculation enhanced the contents of esters and aldehydes, intensifying the flower, sweet and sour fruit of the wines. Partial least-squares regression analysis showed that esters and terpenes contributed greatly to the flower and sweet fruit aroma, whereas aldehydes were the major contributors to the sour note.

CONCLUSION

Based on our results, the mixed fermentations not only enriched the types and concentrations of volatiles, but also had better sensory properties. © 2021 Society of Chemical Industry.

Occurrence of Marine Ingredients in Fragrance: Update on the State of Knowledge

The fragrance field of perfumes has attracted considerable scientific, industrial, cultural, and civilizational interest. The marine odor is characterized by the specific smell of sea breeze, seashore, algae, and oyster, among others. Marine odor is a more recent fragrance and is considered as one of the green and modern fragrances. The smells reproducing the marine environment are described due to their content of Calone 1951 (7-methyl-2H-1,5-benzodioxepin-3(4H)-one), which is a synthetic compound. In addition to the synthetic group of benzodioxepanes, such as Calone 51 and its derivatives, three other groups of chemical compounds seem to represent the marine smell. The first group includes the polyunsaturated cyclic ((+)-Dictyopterene A) and acyclic (giffordene) hydrocarbons, acting as pheromones. The second group corresponds to polyunsaturated aldehydes, such as the (Z,Z)-3,6-nonadienal, (E,Z)-2,6-nonadienal, which are most likely derived from the degradation of polyunsaturated fatty acids. The third group is represented by small molecules such as sulfur compounds and halogenated phenols which are regarded as the main flavor compounds of many types of seafood. This review exposes, most notably, the knowledge state on the occurrence of marine ingredients in fragrance. We also provide a detailed discussion on several aspects of essential oils, which are the most natural ingredients from various marine sources used in fragrance and cosmetics, including synthetic and natural marine ingredients.

Stress Resistance and Adhesive Properties of Commercial Flor and Wine Strains, and Environmental Isolates of Saccharomyces cerevisiae

Flor strains of Saccharomyces cerevisiae represent a special group of yeasts used for producing biologically aged wines. We analyzed the collection of commercial wine and flor yeast strains, as well as environmental strains isolated from the surface of grapes growing in vineyards, for resistance to abiotic stresses, adhesive properties, and the ability to form a floating flor. The degree of resistance of commercial strains to ethanol, acetaldehyde, and hydrogen peroxide was generally not higher than that of environmental isolates, some of which had high resistance to the tested stress agents. The relatively low degree of stress resistance of flor strains can be explained both by the peculiarities of their adaptive mechanisms and by differences in the nature of their exposure to various types of stress in the course of biological wine aging and under the experimental conditions we used. The hydrophobicity and adhesive properties of cells were determined by the efficiency of adsorption to polystyrene and the distribution of cells between the aqueous and organic phases. Flor strains were distinguished by a higher degree of hydrophobicity of the cell surface and an increased ability to adhere to polystyrene. A clear correlation between biofilm formation and adhesive properties was also observed for environmental yeast isolates. The overall results of this study indicate that relatively simple tests for cell hydrophobicity can be used for the rapid screening of new candidate flor strains in yeast culture collections and among environmental isolates.

Aroma and Sensory Profiles of Sauvignon Blanc Wines from Commercially Produced Free Run and Pressed Juices

Sauvignon blanc is the most important grape cultivar within the New Zealand wine industry, and wines from the Marlborough region are renowned for their intense aromas including tropical, passionfruit, and green capsicum. Quality Sauvignon blanc wines are usually made from free run juice, although press fractions can be included. The chemical aroma composition and sensory profiles of two wine sets made from three press fractions (free run, light press and heavy press) were compared. The compounds 3-mercaptohexan-1-ol and 3-mercaptohexyl acetate were found to decrease between free run and heavily pressed wines while hexyl acetate, hexanol, and benzyl alcohol increased. The accompanying sensory analysis showed that free run wines were marked by aromas of Passionfruit/sweaty, Boxwood and Fresh green capsicum, while the heavy pressed wines were described by French vanilla/bourbon, Floral and Banana lolly attributes, consistent with the aroma chemical composition.

Two Sides to One Story-Aroma Chemical and Sensory Signature of Lugana and Verdicchio Wines

Lugana and Verdicchio are two Italian white wines with a Protected Designation of Origin (PDO) label. These two wine types are produced in different regions using the same grape variety. The aim of this work is to investigate the existence of volatile chemical markers that could help to elucidate differences between Lugana and Verdicchio wines both at chemical and sensory levels. Thirteen commercial wine samples were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS), and 76 volatile compounds were identified and quantified. Verdicchio and Lugana had been differentiated on the basis of 19 free and glycosidically bound compounds belonging to the chemical classes of terpenes, benzenoids, higher alcohols, C₆ alcohols and norisoprenoids. Samples were assessed by means of a sorting task sensory analysis, resulting in two clusters formed. These results suggested the existence of 2 product types with specific sensory spaces that can be related, to a good extend, to Verdicchio and Lugana wines. Cluster 1 was composed of six wines, 4 of which were Lugana, while Cluster 2 was formed of 7 wines, 5 of which were Verdicchio. The first cluster was described as “fruity”, and “fresh/minty”, while the second as “fermentative” and “spicy”. An attempt was made to relate analytical and sensory data, the results showed that damascenone and the sum of 3 of esters the ethyl hexanoate, ethyl octanoate and isoamyl acetate, was characterizing Cluster 1. These results highlighted the primary importance of geographical origin to the volatile composition and perceived aroma of Lugana and Verdicchio wines.

Aroma of Sherry Products: A Review

Jerez (Sherry) is a well-known wine-producing region located in southern Spain, where world-renowned oenological products such as wines, vinegars, and brandies are produced. There are several factors that provide characteristic physical, chemical, and sensory properties to the oenological products obtained in this Sherry region: the climate in the area with hot summers, mild winters, and with limited rainfall; the raw material used consisting on Palomino Fino, Moscatel, and Pedro Ximénez white grape varieties; the special vinification with fortified wines; and aging techniques such as a dynamic system of biological or oxidative aging. These special organoleptic characteristics are responsible for, among others, the aromatic profile of the wines, vinegars and brandies from the area, which explains why this is a subject that has been extensively researched over the years. This bibliographic review aims to compile the different scientific contributions that have been found to date, in relation with the aroma of the oenological products from the Sherry area (dry wines, sweet wines, vinegars, and brandies). We have mainly focused on the different analytical methodologies used and on the main analytes of interest.

Influence of Different Vinification Techniques on Volatile Compounds and the Aromatic Profile of Palomino Fino Wines

The aim of this study was to evaluate the influence of vinification techniques on volatile compounds and sensory profiles in young Palomino fino white wines. Four winemaking techniques (pellicular maceration, supra-extraction and use of commercial yeast strains and of β-glycosidase enzymes) were implemented to enhance the aromatic quality of wines elaborated from this neutral variety of grape. Volatile compound content, aromatic profile (OAVs) and sensorial analysis were determined. The results showed that all the vinification techniques studied led to an increase in volatile compounds compared to the control wine. Likewise, an influence of the vineyard and must extraction method on these compounds was observed. However, the greatest changes in aroma activity and sensory profile were a result of the pellicular maceration and supra-extraction techniques. The latter was differentiated by the highest content of terpenes and, consequently, the highest odour activity values of floral series. In addition, the supra-extraction was a very selective technique since it extracted terpenes and aromatic precursors, but not the acids responsible for the fatty characteristic, such as octanoic acid. In terms of sensory profile, the supra-extraction technique improved the intensity of the Palomino fino white wine and its aromatic quality with a previously not-determined floral character.

Evaluation of the Perceptual Interactions Between Higher Alcohols and Off-Odor Acids in Laimao Baijiu by σ-τ Plot and Partition Coefficient

The volatile compounds in three Laimao baijius ("Chuanchenglan, CCL", "Hongyu, HY", and "Zhencang, ZC") were comprehensively analyzed by gas chromatography-olfactometry and gas chromatography-mass spectrometry. The results demonstrated that 44, 42, and 42 compounds with flavor dilution factors ≥ 16 and odor activity values ≥ 1 were, respectively, identified as important odorants. Additionally, the perceptual interactions of 6 higher alcohols and 3 off-odor acids were evaluated by σ-τ plot, and the partition coefficient was calculated to explain the release of odorants in the matrix. The interactions indicated that adding a high concentration of 1-propanol or 2-phenylethanol to the matrix could mask the sweaty note of 3-methylbutyric acid. The partition coefficients explained that high concentrations of 1-propanol and 2-phenylethanol were able to significantly inhibit the release of 3-methylbutyric acid when the phase ratio was relatively large, and the effect of 1-propanol on it was higher than that of 2-phenylethanol.

Evolution of Carotenoid Content, Antioxidant Activity and Volatiles Compounds in Dried Mango Fruits (Mangifera Indica L.)

The aim of this research was to study the evolution of carotenoid compounds, antioxidant β-ctivity, volatiles and sensory quality in two mango cultivars dried at 50, 60 and 70 °C. Total carotenoids in fresh samples were about 12 and 6 mg/100 g (dry basis) in Keitt and Osteen samples, respectively. β-carotene was the main carotenoid, representing about 50% of total carotenoids. In both cultivars, carotenoids were more susceptible to drying at 60 °C. Total phenols and metal reduction activity were higher in Osteen than in Keitt, which had higher values in radical scavenging capacity. The antioxidant activities were best preserved with drying temperatures at 50 °C in Keitt and 60 °C in Osteen fruits. Fresh Osteen mango fruits had a volatile compound content of about 37.1, while Keitt of about 5.2 mg/kg (dry basis). All the compounds with odorous impact were significantly reduced after drying. As regards organoleptic characteristics through sensory analysis, Keitt dried mangoes were quite similar to the fresh product, compared to Osteen.

Volatile and sensory characterization of white wines from three minority Portuguese grapevine varieties

This work focused on the characterization of the volatile compounds and sensory profile of white wines produced from three minority grapevine varieties of Portugal namely ‘Malvasia’ (Colares), ‘Verdelho’ and ‘Galego Dourado’. The characterization took place using sensory and gas chromatography analysis. Furthermore, the data obtained were analysed through the use of multivariate analysis, which made it possible to evaluate the similarities and dissimilarities between the varieties. The results obtained show a differentiation of the wines produced from each grapevine variety but above all a differentiation of the two vintages was verified. The results obtained, both from a sensory and a chemical point of view, show an interesting oenological potential of these varieties, but still require further studies, in order to evaluate the influence of climatic effects on the profile of volatile compounds and also on the sensory profile.

Changes in the physicochemical components, polyphenol profile, and flavor of persimmon wine during spontaneous and inoculated fermentation

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

Influence of Native Saccharomyces cerevisiae Strains from D.O. “Vinos de Madrid” in the Volatile Profile of White Wines

Yeasts during alcoholic fermentation form a vast number of volatile compounds that significantly influence wine character and quality. It is well known that the capacity to form aromatic compounds is dependent on the yeast strain. Thus, the use of native yeast strains, besides promoting biodiversity, encourages the conservation of regional sensory properties. In this work, we studied the volatile profile of Malvar wines fermented with 102 Saccharomyces cerevisiae yeast strains, isolated from vineyards and cellars belonging to the D.O. “Vinos de Madrid”. The wines elaborated with different S. cerevisiae showed a good classification by cellar of origin. Additionally, seven sensory descriptors have helped to classify the wines depending on their predominant aromatic character. Twenty-nine Saccharomyces strains, belonging to five of six cellars in the study, were characterized by producing wines with a fruity/sweet character. Floral, solvent, and herbaceous descriptors are more related to wines elaborated with Saccharomyces strains from organic cellars A, E, and F. Based on these findings, winemakers may use their best native S. cerevisiae strains, which add personality to their wine. Therefore, this study contributes to promoting the use of native Saccharomyces yeasts in winemaking.

Determination of Key Volatile Compounds Related to Long-Term Fermentation of Soy Sauce

The changes of volatile compounds in soy sauce during long-term fermentation (12 months) were investigated using solid-phase microextraction (SPME) and stir bar sorptive extraction (SBSE). A total of 144 and 129 compounds were identified in soy sauce with long-term fermentation by SPME and SBSE, respectively. The contents of most compounds, such as acids, aldehydes, benzene and benzene derivatives, esters, lactones, pyrazines, pyrones, and pyrroles, showed a tendency to increase, whereas those of alcohols and ketones decreased according to long-term fermentation. In addition, principal component analysis and partial least squares discriminant analysis were applied to discriminate soy sauce samples according to fermentation periods and determine key volatile compounds related to long-term fermentation. The initial fermentation stages were mainly associated with some alcohols, ketones, and lactones, whereas the later stages were strongly associated with most esters, some phenols, benzene and benzene derivatives, and pyrroles. Moreover, the key volatile compounds associated with long-term fermentation in soy sauce samples were ethyl 3-methylbutanoate (ethyl isovalerate), ethyl pentanoate (ethyl valerate), 1-octen-3-yl acetate, 3-(methylthio)-1-propanol (methionol), ethyl benzoate, ethyl 2-phenylacetate, 1-(1H-pyrrol-2-yl)ethanone (2-acetylpyrrole), and 5-pentyl-2-oxolanone (γ-nonalactone). PRACTICAL APPLICATION: This study investigated changes of volatile compounds in soy sauce during long-term fermentation (12 months) using solid-phase microextraction and stir bar sorptive extraction. In addition, the key volatile compounds associated with long-term fermentation in soy sauce samples were determined. These results may help to predict the effective contributors related to long-term fermentation of soy sauce and improve the quality of soy sauce during long-term fermentation.

The potential aroma and flavor compounds in Vitis sp. cv. Koshu and V. vinifera L. cv. Chardonnay under different environmental conditions

BACKGROUND

Koshu, a hybrid of Vitis vinifera L. and V. davidii Foex, is the most popular indigenous cultivar for wine production in Japan. However, little is known about the potential aroma compounds it contains and how environmental factors affect these. In this study, we obtained comprehensive profiles of the volatile (both glycosidically bound and free) and phenolic compounds that occur in koshu berries, and compared these with similar profiles for V. vinifera cv. chardonnay. We then compared the response of these two cultivars to bunch shading and the ripening-related phytohormone abscisic acid (ABA).

RESULTS

Koshu berries contained significantly higher concentrations of phenolic compounds, such as hydroxycinnamic acid derivatives, and some volatile phenols, such as 4-vinyl guaiacol and eugenol, than chardonnay berries, which are thought to contribute to the characteristics of koshu wine. In addition, koshu berries had a distinctly different terpenoid composition from chardonnay berries. Shading reduced the concentration of norisoprenoid in both cultivars, as well as several phenolic compounds, particularly their volatile derivatives in koshu berries. The exogenous application of ABA induced ripening and increased the concentrations of lipid derivatives, such as hexanol, octanol, 1-nonanol, and 1-octen-3-ol. Multivariate and discriminant analyses showed that the potential aroma and flavor compounds in the berries could be discriminated clearly based on cultivar and environmental cues, such as light exposure.

CONCLUSION

The unique secondary metabolite profiles of koshu and their different responses to environmental factors could be valuable for developing various types of koshu wines and new cultivars with improved quality and cultural characteristics. © 2018 Society of Chemical Industry.

Immobilisation of yeasts on oak chips or cellulose powder for use in bottle-fermented sparkling wine

Sparkling wine production comprises two successive fermentations performed by Sacharomyces cerevisiae strains. This research aimed to: develop yeast immobilisation processes on two wine-compatible supports; study the effects of yeast type (IOC 18-2007 and 55A) and the immobilisation support type (oak chips and cellulose powder) on the fermentation kinetics, the deposition rate of lees and the volatile composition of the finished sparkling wine; compare the fermentation parameters of the wines inoculated with immobilised or non-immobilised cells. Proper immobilisation of yeast on oak chips and cellulose powder was demonstrated by electron microscopy. Total sugar consumption occurred in under 60 days in all bottles, regardless of the strain used and the way they were inoculated in wine. Deposition of lees was 3-fold faster in the bottles containing immobilised cells than in those with free cells; no addition of adjuvants was necessary. The analysis of the volatile compounds of the finished sparkling wines showed significant differences in the formation of esters, acids, alcohols, aldehydes and lactones according to the yeast and the immobilisation support used. Oak chips were the more appropriate support for yeast immobilisation. No significant differences in the sensorial analysis of the sparkling wines produced by the different strategies were found.

Volatile aroma compounds in wines from Chinese wild/hybrid species

The volatile aroma compounds in wines produced from Chinese wild/hybrid species were investigated in comparison to wines from European grapes. Volatiles were extracted by headspace solid-phase micro-extraction and identified by gas-chromatography/mass-spectrometry. The identification of analyte was performed by a combination of the linear retention index approach with the comparison of the obtained mass spectra. A total of 98 peaks were tentatively assigned as wine aroma components, and 15 odorants can be found at concentrations above their odor threshold among the odor activity values (OAVs) of 46 compounds evaluated in all of the wines. The "OAVs' aroma wheels" showed that the classes of aromatic series are first fruity, next herbaceous and roasty and no spicy and caramelized notes. Via principal component analysis, all the grape germplasm studied could be divided into four groups: "Jingsheng-1," "Cabernet Gernischt," "Beibinghong," and others, which exhibited distinctive aroma features, respectively. Practical applications Chinese wild grape species have many desirable properties for wine grape breeding such as possessing strong resistant genes to fungal diseases and cold condition, especially after hybridization with European grapes. As an emerging wine country, wines from Chinese wild/hybrid species have achieved much success in the last few years. The chemical content and biological properties have been studied extensively in many but there are a few studies in our knowledge about the wine tastes of these species. In this paper, the key odorants in wines produced from the Chinese grape species of V. amurensis Rupr., V. davidii Foex., and V. quinquangularis Rehd. and its hybrids were characterized in comparison to wines produced from European grapes (V. vinifera). The findings will help to the further understanding of the key aroma components in the different Chinese grapevine germplasm, and make further efforts to enrich the wine types in the marketplace.

Chemical and sensory characterization of the aroma of ‘Chardonnay’ musts fermented with different nitrogen sources

This work studies the influence of two different nitrogen sources added to the must on aromatic series and sensory profile of ‘Chardonnay’ wines. Volatile compounds were classified into six odorant series and the total intensities for every aromatic series were calculated as sum of the OAV of each one of the compounds assigned to these series. Sensory profile was defined by quantitative descriptive sensory analysis. The fruity, floral and sweet series are the ones most strongly contributing to the aroma of ‘Chardonnay’ wines, independently of nitrogen source added. In general, the fortification of must with nitrogen source enhances the aroma intensity of wines, especially fruity and floral notes. Samples with organic nutrient presented greater aromatic intensity and more floral aromas than samples with inorganic nutrient. According to the results, the fortification of must with organic nitrogen enhanced the aromatic complexity of wines.

Simultaneous determination of diethylacetal and acetaldehyde during beer fermentation and storage process

BACKGROUND

Acetaldehyde is an important flavor component in beer which is possibly carcinogenic to humans. Owing to the limitations of present detection methods, only free-state acetaldehyde in beers has been focused on, while acetal in beers has hardly been reported so far.

RESULTS

A sensitive headspace gas chromatography method was developed for the determination of diethylacetal and acetaldehyde in beer. The column DB-23 was chosen with a total run time of 22.5 min. The optimal addition amount of NaCl, equilibrium temperature and equilibrium time were 2.0 g, 70 °C and 30 min respectively. For both diethylacetal and acetaldehyde analyses, the limit of detection was 0.005 mg L^-1 with relative standard deviation < 5.5%. The recoveries of acetaldehyde and diethylacetal were 95-110 and 95-115% respectively. The diethylacetal and acetaldehyde average contents in 24 beer products were 11.83 and 4.36 mg L^-1 respectively. The Pearson correlation coefficient between diethylacetal and acetaldehyde was the highest (0.963). Both diethylacetal and acetaldehyde contents increased to a peak value after fermentation for 3 days and then decreased to a lower value. During both normal and forced aging storage, the diethylacetal content decreased and the acetaldehyde content increased gradually over time. When beers were forced aged for 4 days, the increased ratio of acetaldehyde could be above 40.00%.

CONCLUSION

The newly established method can be used to assess acetaldehyde level and flavor quality in beer more scientifically. © 2018 Society of Chemical Industry.

The impact of postharvest ultra-violet light irradiation on the thiol content of Sauvignon blanc grapes

Sauvignon blanc grapes were exposed to an ultra-violet (UV) light source post-hand harvest (whole bunches) or post-machine harvest. The thiol precursors S-3-(hexan-1-ol)-l-cysteine (Cys-3MH) and S-3-(hexan-1-ol)-l-glutathione (GSH-3MH) were quantified in the juices before and after UV treatment. Results showed that irradiation of the grapes with UV light had little to no effect on the thiol precursors. Wines were fermented from the corresponding juices and 18 aroma compounds were quantified. Differences were found between UV treatments of the wines for 3-mercaptohexanol, hexan-1-ol, ethyl butanoate, ethyl hexanoate, ethyl octanoate and phenylethyl alcohol. However, these changes were not significant (p < 0.05) for both grape media trialled. Future studies involving larger sample sizes and replicate numbers should be completed in order to ascertain any changes in aroma chemistry as a result of UV light application to grapes postharvest.

Harvesting and blending options for lower alcohol wines: a sensory and chemical investigation

BACKGROUND

Lower alcohol wines often have a poor reputation among consumers, in part due to their unsatisfactory flavours such as reduced overall aroma intensity or herbaceous characters. The aim of this study, performed on Verdelho and Petit Verdot, was to quantify the effectiveness of a monovarietal blend in which wines made from less ripe grapes were blended with an equivalent volume of a wine vinified from riper fruit to produce wines with a lower alcohol content and desirable ripe fruit flavours.

RESULTS

Eleven and 13 attributes, for Verdelho and Petit Verdot, respectively, were selected during sensory descriptive analysis. Intensities of perceived 'acidity', 'sweetness' and 'alcohol' attributes were significantly different (P ≤ 0.05) between the blend (8.8 ± 0.1% v/v) and mature Verdelho (10.3 ± 0.1% v/v) wines, while no significant differences were found between the Petit Verdot blend (11.0 ± 0.1% v/v) and mature (12.6 ± 0.2% v/v) treatments. Volatile composition of wines was assessed using HS-SPME-GC-MS. Partial least square regression suggested relationships between sensory descriptors and chemical attributes in the wines, as well as the modifications of sensory and compositional profiles following blending.

CONCLUSIONS

The blending practice described allowed the production of wines with lower alcohol content while retaining similar sensory profiles of the later harvested, riper fruit wines. © 2017 Society of Chemical Industry.

Influence of Fermentation Temperature, Yeast Strain, and Grape Juice on the Aroma Chemistry and Sensory Profile of Sauvignon Blanc Wines

Sauvignon blanc wine, balanced by herbaceous and tropical aromas, is fermented at low temperatures (10-15 °C). Anecdotal accounts from winemakers suggest that cold fermentations produce and retain more "fruity" aroma compounds; nonetheless, studies have not confirmed why low temperatures are optimal for Sauvignon blanc. Thirty-two aroma compounds were quantitated from two Marlborough Sauvignon blanc juices fermented at 12.5 and 25 °C, using Saccharomyces cerevisiae strains EC1118, L-1528, M2, and X5. Fourteen compounds were responsible for driving differences in aroma chemistry. The 12.5 °C-fermented wines had lower 3-mercaptohexan-1-ol (3MH) and higher alcohols but increased fruity acetate esters. However, a sensory panel did not find a significant difference between fruitiness in 75% of wine pairs based on fermentation temperature, in spite of chemical differences. For wine pairs with significant differences (25%), the 25 °C-fermented wines were fruitier than the 12.5 °C-fermented wines, with high fruitiness associated with 3MH. We propose that the benefits of low fermentation temperatures are not derived from increased fruitiness but a better balance between fruitiness and greenness. Even so, since 75% of wines showed no significant difference, higher fermentation temperatures could be utilized without detriment, lowering costs for the wine industry.

Influence of Freeze Concentration Technique on Aromatic and Phenolic Compounds, Color Attributes, and Sensory Properties of Cabernet Sauvignon Wine

Red wines produced in the Xinjiang region of China possess poor color density, and lack fruity notes and elegance. The freeze concentration technique, as a well-established concentration method for liquid food systems, was applied to the Cabernet Sauvignon (Vitis vinifera L.) wine-making process, aiming to investigate its effect on wine quality improvement. Results showed that the freeze concentration treatment did not significantly alter the physicochemical properties of the wine, except for an increase of glycerol and alcoholic content. This technique increased ester contents, as well as decreasing the amount of volatile acids. Higher alcohol contents were also increased, but within an acceptable content range. All taken into consideration, the freeze concentration treated wine showed better fragrance characters according to sensory evaluation. The non-anthocyanin composition was altered by this application, however, the difference disappeared after the aging process. Fortunately, sensory evaluation showed that the treated wine possessed better mouthfeel properties. Anthocyanin contents were enhanced, and effectively stabilized the fresh wine color attributes, resulting in an improvement in appearance of the treated wine. All results considered, it can be concluded that freeze concentration treatment could be a good choice to improve wine quality.

Moscatel vine-shoot extracts as a grapevine biostimulant to enhance wine quality

Non-aromatic vine-shoot extracts (Airén) has been recently proposed as "viticultural biostimulants" when applied to grapevine. In this paper, the application of extracts from non-toasted (MVS) and toasted (MVS_Toasted) vine-shoots from the well-known aromatic variety such Moscatel were applied on Airén grapevine leaves, observing an increased for grape yield and wines with a lower alcohol degree. All wines at the end of the alcoholic fermentation were characterized by their fruity and floral descriptors, especially MVS wines; and 4 months later, MSV and MVS_Toasted wines surprised by their higher spicy notes, which correspond with the highest OAVs values for compounds such as norisoprenoids (β-damascenone), vanillin derivatives (vanillin, acetovanillone) and volatile phenols (guaiacol, syringol), compared to control wine. Wine phenolic composition was affected positively over all by MVS in case of phenolic acids. These results confirm that Moscatel vine-shoot extracts foliar application into Airén non-aromatic grapevines produce an interesting enhance on wine quality.

Differentiation of Commercial PDO Wines Produced in Istria (Croatia) According to Variety and Harvest Year Based on HS-SPME-GC/MS Volatile Aroma Compound Profiling

To differentiate monovarietal wines made from native and introduced varieties in Istria (Croatia), samples of Malvazija istarska, Chardonnay and Muscat yellow from two harvest years (2013 and 2014) were subjected to headspace solid-phase microextraction and gas chromatographic/mass spectrometric analysis (HS-SPME-GC/MS) of volatile aroma compounds. Significant effects of variety and harvest year were determined, but their interaction complicated the differentiation. Particular compounds were consistent as markers of variety in both years: nerol for Malvazija, ethyl cinnamate and a tentatively identified isomer of dimethylbenzaldehyde for Chardonnay, and terpenes for Muscat yellow. Wines from 2013 contained higher concentrations of the majority of important volatiles. A 100% correct differentiation of Malvazija istarska and Chardonnay wines according to both variety and harvest year was achieved by stepwise linear discriminant analysis.