Validation of a LLME/GC-MS Methodology for Quantification of Volatile Compounds in Fermented Beverages

Exploring the Influence of Toasting Levels, Grain Sizes, and Their Combination on the Volatile Profile of Tempranillo Red Wines Aged in Quercus petraea Barrels

The ageing of wine in oak barrels enhances its sensory properties, with the toasting level and grain size of the wood significantly influencing the volatile composition of the wine. This study evaluated the impact of three toasting levels (light toasting, medium toasting, and medium long toasting) and two grain sizes (standard grain and extra fine grain) on the volatile profile of Tempranillo red wines aged in Quercus petraea barrels over 12 and 18 months. Gas chromatography-mass spectrometry was employed to quantify wine volatile compounds. The results revealed that lighter toasting combined with standard grain barrels enhanced the wine volatile concentration during shorter maturation periods, while medium long toasting with extra fine grain barrels was more effective for longer ageing periods. Toasting level was found to have a stronger influence on the wine volatile composition than grain size. These findings underscore the importance of tailoring barrel specifications to the desired maturation durations and sensory outcomes. Future studies exploring other grape varieties, wood origins, and longer ageing periods could further refine these insights and enhance winemaking practices.

Subpopulation-specific gene expression in Lachancea thermotolerans uncovers distinct metabolic adaptations to wine fermentation

Gene expression is the first step in translating genetic information into quantifiable traits. This study analysed gene expression in 23 strains across six subpopulations of Lachancea thermotolerans, shaped by anthropization, under winemaking conditions to understand the impact of adaptation on transcriptomic profiles and fermentative performance, particularly regarding lactic acid production. Understanding the gene expression differences linked to lactic acid production could allow a more rational address of biological acidification while optimizing yeast-specific nutritional requirements during fermentation. By sequencing mRNA during exponential growth and fermentation in synthetic grape must, we identified unique expression patterns linked to the strains originated from wine-related environments. Global expression analysis revealed that anthropized subpopulations, particularly Europe/Domestic-2 and Europe-Mix, exhibited distinct gene expression profiles related to fermentation processes such as glycolysis and pyruvate metabolism. These processes were differentially expressed, along with other important biological processes during fermentation, such as nitrogen and fatty acid metabolism. This study highlights that anthropization has driven metabolic specialization in L. thermotolerans, enhancing traits like lactic acid production, which is a trait of interest in modern winemaking. Correlation analysis further linked lactic acid dehydrogenase genes with key metabolic pathways, indicating adaptive gene expression regulation. Additionally, differences in other metabolites of oenological interest as glycerol or aroma compounds production are highlighted. Here, we provide insights into the evolutionary processes shaping the transcriptomic diversity of L. thermotolerans, emphasizing the impact of winemaking environments on driving specific metabolic adaptations, including lactic acid production.

The Influence of Quercus alba Geographical Location and Aging Time on the Chemical and Sensory Quality of Tempranillo Wines

The changes produced during the aging of wines in oak barrels are strongly dependent on the oak's geographical origin and aging time. This paper analyzes the effect of Quercus alba oak from four different geographical locations in four states in the USA, namely Missouri (Mo), Ohio (Oh), Kentucky (Kt), and Pennsylvania (Py), during 24 months of aging. Oak origin had a higher effect on the wine's aromatic composition than the polyphenolic one. Mo and Oh barrels enhanced coconut, spicy, and sweet notes for 12 months of aging, while Kt barrels achieved higher extraction of wood-related compounds at longer aging (24 months). Py wines showed the lowest contents of most volatile compounds at both aging times, as well as hydroxycinnamic acids, flavanols, anthocyanins, flavonols, stilbenes, and ellagitannins, attributed to their higher porosity. At 12 months of aging, Kt wines showed the highest content of ellagitannins, and Mo wines had the highest content of anthocyanins, but Oh wines had the highest concentrations at 24 months. In the sensory analysis, Kt wines were preferred at both aging times. Kt and Mo wines achieved the highest punctuations for the olfactory phase at 12 months of aging and Kt wines kept it after 24 months. These findings are essential for producers to achieve the sensory characteristics of their wines through strategic barrel aging.

Comparative characterization and contribution of key aroma compounds in the typical base liquor of Jiang-flavor Baijiu from different distributions in the Chinese Chishui River basin

The characteristic of typical base liquor is crucial in controlling ultimate quality of Jiang-flavor Baijiu. This study investigates the flavor compounds of three typical base liquors (Jiangxiang, Chuntian, and Jiaodixiang) by LLE/LLME/HS-SPME, gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame ionization detection (GC-FID), sensory analysis, and odor activity value (OAV). Of the 201 main volatile compounds identified, 37 significant compounds distinguished the three typical base liquors. Acid (441.72 ± 0.17 mg/L), alcohol (5388.88 ± 0.55 mg/L), and ester compounds (8181.64 ± 0.15 mg/L) were respectively marked in Jiangxiang, Chuntian, and Jiaodixiang typical base liquors. Orthogonal partial least squares discriminant analysis (OPLS-DA), correlation analysis, and aroma recombination showed that butyric acid (OAV: 102.23), butyl 2-methylbutyrate (OAV: 6045.59), and ethyl caproate (OAV: 418.37) were significantly correlated with sweet, fruity, pit mud, jiang, and ethanol aromas. It identifies the primary constituents that affect flavor variations in the three typical base liquors and provides guidance for investigations on the flavor formation of Jiang-flavor Baijiu.

Comparative study of e-cigarette aerosol and cigarette smoke effect on ex vivo embryonic chick lung explants

Electronic cigarette usage has significantly expanded among young people and pregnant women in the last decade. Although there are already some data regarding the short- and long-term consequences of e-cigarettes on human health, their effect on embryo and lung development still needs to be fully disclosed. In this sense, this study describes, for the first time, the impact of electronic cigarette aerosol on early lung development. For this purpose, ex vivo chick (Gallus gallus) embryonic lungs were cultured in vitro for 48 h in e-cigarette aerosol exposed-medium or unexposed medium. Chick lung explants were also cultured in a cigarette smoke-exposed medium for comparison purposes. Lung explants were morphologically analyzed to assess the impact on lung growth. Additionally, TNF-α levels were determined in the supernatant as a marker of pro-inflammatory response. The results suggest that electronic cigarette aerosol impairs lung growth and promotes lung inflammation. However, its impact on early lung growth seems less detrimental than conventional cigarette smoke. This work provides significant data regarding the impact of e-cig aerosol, adding to the efforts to fully understand its effect on embryo development. The validation of these effects may eventually lead to new tobacco control recommendations for pregnant women.

Effect of Early Basal Leaf Removal on Phenolic and Volatile Composition and Sensory Properties of Aglianico Red Wines

The aim of this work was to study the influence of early basal leaf removal on Aglianico wines produced in the Apulia region (Italy). Three treatments were carried out, where 100% of fruit-zone leaves on the north (DN), south (DS) and on both sides of the canopy (DNS) were removed. A control (CT), where all basal leaves were retained, was also performed. Instrumental (HPLC-DAD-MS and GC-MS) and sensory analysis (QDA) were used to evaluate the treatment effect on the phenolic and volatile compositions and on the sensory descriptors of wines. DNS reached the highest amounts of phenolic compounds, showing a change in the phenolic pattern from flavonols and anthocyanins. Moreover, leaf removal influenced the levels of 37.8% of volatile compounds, quantified by increasing the concentration when early leaf removal was applied on the north side of the canopy (DN), with respect to the south (DS) and both sides (DNS). In the sensory analysis, Aglianico wines were defined by 16 sensory attributes with GM > 30%, where the highest values were reached for defoliation treatments vs. control. In conclusion, early leaf removal treatments allowed us to modulate the phenolic and volatile concentrations of Aglianico wines.

Tejuino, a Traditional Fermented Beverage: Composition, Safety Quality, and Microbial Identification

This study aims to analyze the chemical and microbial composition and characterize volatile compounds from the artisanal and commercial Tejuino beverage. For this, eight samples are analyzed (four artisanal and four commercial). The chemical and microbiological quality is determined by standard methods, and volatile compounds are determined by solid-phase microextraction. Overall, the physicochemical composition and microbiological quality are higher for artisanal Tejuino (p < 0.05). The pH values were 3.20 and 3.62, and 0.76 and 0.46 meq of lactic acid for artisanal and commercial Tejuino, respectively. With volatile compounds analyzed, esters, benzenes, and aldehydes were predominant; meanwhile, ethanol was a volatile compound with the highest concentration for all samples. Saccharomyces cerevisiae and Limosilactobacillus fermentum were identified in artisanal Tejuino; yeasts of the Pichia genera and Lactiplantibacillus plantarum, for commercial Tejuino, and Enterococcus genus were identified in both samples. The characterization of both types of Tejuino allows us to update the information available on this important Mexican beverage. In addition, the isolation of lactic acid bacteria, as representative bacteria of both drinks, offers an area of opportunity to know the potential functionality of these bacteria in traditional fermented products.

Rootstock Effect on Volatile Composition of Albariño Wines

Background: Rootstock is a viticultural practice used to combat the devastating Phylloxera vitifoliae (Fitch). Additionally, it is well-known that wine aroma composition depends mainly on variety, viticulture management and winemaking; therefore, rootstocks can affect to berry quality. This study evaluated the influence of nine rootstocks (110R, SO4, 196-17C, Riparia G, 161-49C, 420A, Gravesac, 3309C and 41B) on volatile composition of Albariño wine in two consecutive vintages. Material and Methods: Volatile compounds belonging to eight groups (alcohols, C6-compounds, ethyl esters+acetates, terpenes + C13-norisoprenoids, volatile phenols, volatile acids, lactones and carbonyl compounds) were determined in Albariño wines by GC–MS, during 2009 and 2010 vintages. Results: Rootstock 110R had a positive influence on Albariño wines, increasing total volatile concentration, due mainly to 2-phenylethanol, decanoic and hexanoic acids, ethyl esters and acetates, and C13-norisoprenoids. However, the higher contribution of volatile fatty acids to Albariño wine was shown when grapevines were grafted onto SO4. Conclusions: This work provides new information about the impact of rootstocks on Albariño wine volatile composition, where 110R had a positive influence on Albariño wines under the edaphoclimatic conditions of Salnés Valley (Galicia, Spain).

Application of Autochthonous Yeast Saccharomyces cerevisiae XG3 in Treixadura Wines from D.O. Ribeiro (NW Spain): Effect on Wine Aroma

Yeast plays an essential role in winemaking. Saccharomyces cerevisiae strains involved in fermentation determine the chemical and sensory characteristics of wines. S. cerevisiae XG3, isolated in Galicia (NW Spain), has desirable oenological potential, which has been proved at a pilot scale to produce quality wines. This study applies XG3 as active dry yeast at an industrial scale for Treixadura wine elaboration, and compares it with commercial yeast and spontaneous fermentation within three wineries included in Denomination of Origin Ribeiro over two vintages. Fermentations are monitored using conventional methods, and microbiological implantation controls are carried out by mtDNA-RFLPs analysis. Wine basic chemical parameters are determined using OIV official methodology, and volatile aroma compounds are determined by GC-MS. Finally, wine sensory analysis is also performed. S. cerevisiae XG3 shows an acceptable implantation ability—as compared to commercial control strains. The wines from XG3 have a higher total acidity and lower alcohol content. Their volatile composition differs from control wines, since XG3 produces significantly higher concentrations of acetates, volatile acids, esters and volatile phenols, depending on the vintage and winery. However, lower differences are perceived at the sensory level, where fruity and floral descriptors are perceived by the panellists in XG3 wines. Therefore, XG3 constitutes an alternative to differentiate Treixadura wines.

Aroma Profile and Chemical Composition of Reverse Osmosis and Nanofiltration Concentrates of Red Wine Cabernet Sauvignon

Wine aroma represents one of the main properties that determines the consumer acceptance of the wine. It is different for each wine variety and depends on a large number of various chemical compounds. The aim of this study was to prepare red wine concentrates with enriched aroma compounds and chemical composition. For that purpose, Cabernet Sauvignon red wine variety was concentrated by reverse osmosis (RO) and nanofiltration (NF) processes under different operating conditions. Different pressures (2.5, 3.5, 4.5 and 5.5 MPa) and temperature regimes (with and without cooling) were applied on Alfa Laval LabUnit M20 equipped with six composite polyamide RO98pHt M20 or NF M20 membranes. Higher pressure increased the retention of sugars, SO₂, total and volatile acids and ethanol, but the temperature increment had opposite effect. Both membranes were permeable for water, ethanol, acetic acid, 4-ethylphenol and 4-ethylguaiacol and their concentration decreased after wine filtration. RO98pHt membranes retained higher concentrations of total aroma compounds than NF membranes, but both processes, reverse osmosis and nanofiltration, resulted in retentates with different aroma profiles comparing to the initial wine. The retention of individual compounds depended on several factors (chemical structure, stability, polarity, applied processing parameters, etc.).

Chemical composition and sensory properties of Albariño wine: Fertigation effects

Interannual climate variability and management practices, including fertigation, can alter volatile compound concentrations in wines from a given grapevine cultivar. These compounds are highly relevant for wine aroma. The current study aimed to assess the effect of two levels of fertigation on the volatile composition and sensory properties of wines from Albariño grown in two vineyards in NW Spain over three years. Treatments were fertigation to 60% (F-60) and 100% (F-100) of crop needs since budbreak, and a rain-fed control (F-0). Volatile compounds were determined through gas chromatography and mass spectrometry (GC-MS) and wine sensory evaluation was performed by nine experts using quantitative descriptive analysis. General chemical parameters of wines were similar among treatments; however, F-60 and F-0 slightly reduced volatile total concentrations in both vineyards. Wines from the fertigation treatments had greater concentrations of volatile fatty acids, ethyl esters, acetates and C6 compounds. However, terpene concentrations slightly decreased when fertigation was applied. Higher alcohols showed a different behavior between vineyards, mainly related with grapevine water status during the growing season. Seven sensory descriptors differed significantly between vineyards. This study indicates that fertigation could be a tool for modulating wine chemical and sensory characteristics.

Production of a Distilled Spirit Using Cassava Flour as Raw Material: Chemical Characterization and Sensory Profile

Cassava plays a key role in the food production and economies of several countries worldwide. Due to its starch content, alcoholic fermentation is a promising transformation process for adding value to cassava. However, most of the existing cassava beverages are from traditional origin, with the yields and quality often poorly known or controlled due to the use of artisanal production processes. This work aims at the application of easily implementable biotechnological tools for the production of cassava spirits, in order to add value to this raw material. Cassava flour was liquefied and saccharified using enzymatic cocktails, generating a fermentable broth with ~184 g L⁻¹ of fermentable sugars. This was then fermented into an alcoholic product with ~10% ethanol by volume and distilled for spirit production. Cassava spirits with 40% ethanol by volume, with or without application of oak wood, were produced. For further valorization, volatile fractions of cassava spirits were characterized by gas chromatography–flame ionization detection (GC-FID) and GC–MS. These showed a predominance of yeast fermentation metabolites, complemented by wood extractives where oak chips were applied. Both produced spirits showed desirable sensory traits, receiving good acceptance by experienced tasters, demonstrating the feasibility of the proposed process to add value to cassava surplus.

Volatile Esters and Fusel Alcohol Concentrations in Beer Optimized by Modulation of Main Fermentation Parameters in an Industrial Plant

Contents of selected volatile esters and fusel alcohols and their relation to the sensory quality of a bottom-fermented lager beer fermented under high-gravity conditions (15.5 °P) were analyzed using response surface methodology (RSM, Box–Behnken design). The influence of various pitching rates (6–10 mln cells/mL), aeration levels (8–12 mgO2/mL), times (4.5–13.5 h) of filling CCTs (cylindroconical fermentation tanks; 3850 hL), and fermentation temperatures (8.5–11.5 °C) on the contents of selected esters, as well as on concentrations of amyl alcohols and on the sum of higher alcohols in beer, was determined in a commercial brewery fermentation plant. Beers produced throughout the experiments met or exceeded all criteria established for a commercial, marketed beer. Statistical analyses of the results revealed that within the studied ranges of process parameters, models with diversified significance described the concentrations of volatiles in beer. The multiple response optimization procedure analyses showed that the values of process parameters that minimized higher alcohols in beer (97.9 mg/L) and maximized its ethyl acetate (22.0 mg/L) and isoamyl acetate (2.09 mg/L) contents, as well as maximized the sensory quality of beer, (66.4 pts) were the following: Pitching rate 10 mln cells per mL; fermentation temperature 11.5 °C; aeration level 8.8 mg/L; and CCT filling time 4.5 h.

Evaluation of multi-starter S. cerevisiae/ D. bruxellensis cultures for mimicking and accelerating transformations occurring during barrel ageing of beer

During beer ageing, endogenous barrel microbes grow spontaneously and transform wort/beer composition, being Dekkera bruxellensis and Saccharomyces cerevisiae among the main contributors to the chemical and sensory profile of aged beer. This work aims at the application of multi-starter cultures to mimic and accelerate biological modifications occurring during barrel ageing of beer, in controlled fermentation processes. Co-cultures of D.bruxellensis/S.cerevisiae were conducted under conditions commonly found in barrel aged beer production: different pitching rates, high glucose concentration and presence of ethanol and wood extracts. Selective pressures and competition between yeasts influenced microbial growth and metabolite production, namely ethanol, acetic acid and target volatile compounds (esters, alcohols, terpenols, volatile acids and volatile phenols). Metabolic profiles of co-cultures combined traits of both species, and differed from those of pure cultures. Lastly, multi-starters were successfully applied in combination with wood in a controlled and accelerated fermentation process for mimicking barrel ageing transformations.