Acid In Wine Research Articles

Fatty Acid Profiling in Greek Wines by Liquid Chromatography–High-Resolution Mass Spectrometry (LC-HRMS)

In recent years, the interest in lipids present in wines has increased, because these natural components, even at low or very low concentrations, play an important role in wine evolution and quality and contribute substantially to the taste and mouthfeel of wines. Herein, we present a liquid chromatography–high-resolution mass spectrometry (LC-HRMS) method for the profiling of free fatty acids (FFAs) in wines. The method is fast and allows the simultaneous determination of twenty-seven saturated and unsaturated FFAs in wine samples, avoiding any prior derivatization step. After validation, a variety of white and rose commercial wine samples from the Greek market, either sparkling or non-sparkling, were analyzed by the present method. The majority of wine FFAs are saturated long aliphatic, in particular palmitic (C16:0) and stearic (C18:0) acids, followed by myristic (C14:0) and pentadecanoic (C15:0) acids, while oleic (C18:1), palmitoleic (C16:1) and linoleic (C18:2) acids were quantified among the unsaturated FAs. The medium-chain C6:0 and the unsaturated C16:1 and C18:2 acids were found at higher concentrations in rose wines compared to white.

Novel Pseudo-Two-Dimensional 19F NMR Spectroscopy for Rapid Simultaneous Detection of Amines in Complex Mixture.

Rapid detection of amines in complex mixtures presents a significant challenge. Here, we introduce a novel nuclear magnetic resonance (NMR) method for amine detection utilizing a probe with two fluorine atoms in distinct chemical environments. Upon interaction with an amine, the probe generates two atomic resonance peaks, which are used to create coordinates, revealing fluorine chemical shifts on the 19F NMR spectroscopy. This innovative approach allows for the clear distinction of amine signals in a two-dimensional plane. This method has been effectively employed in analyzing amines in pharmaceuticals and amino acids in Ophiopogon japonicus and dry white wine, providing a robust and general approach for amine analysis.

A novel Co/Zn-ferrite molecularly imprinted polymer-based electrochemical assay for sensing of gallic acid in plant extracts, wine, and herbal supplement.

In this study, a new molecularly imprinted polymer (MIP)-based sensor platform was developed for the electrochemical determination of gallic acid (GAL) in plant extracts, wine, and herbal supplements. Gallic acid is known for its natural antioxidant properties, which play an important role in preventing cell deterioration that can lead to various diseases. In addition, gallic acid has therapeutic potential due to its anticancer, antiinflammatory, antimicrobial, and neuroprotective properties. Accurate analysis of gallic acid in complex matrices, in mixed samples where different components coexist, is necessary to evaluate the efficacy and safety of this compound. Cobalt ferrite-zinc-dihydro caffeic acid (CFO_Zn_DHCA) nanoparticles, sphere-like in shape and 5 ± 1nm in size, were incorporated into the MIP-based electrochemical sensor design to enhance the active surface area and porosity of the glassy carbon electrode (GCE) surface. The functional monomer chosen for this study was aminophenyl boronic acid (3-APBA). In the GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor, which was developed using photopolymerization (PP), 3-APBA as a functional monomer was designed, and obtained in the presence of basic monomer (HEMA), cross-linker (EGDMA), and initiator (2-hydroxy-2-methyl propiophenone) by keeping it under a UV lamp at 365nm. It aims to detect GAL in real samples such as Punica granatum (pomegranate) peel, Camellia sinensis (green and black tea leaves), wine, and herbal supplements. Morphological and electrochemical characterizations of the designed GAL/CFO_Zn_DHCA/3-APBA@MIP-GCE sensor were carried out using scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The linear range for the determination of GAL using the indirect method (5.0mM [Fe(CN)6]-3/-4) was found to be 1.0 × 10-13M-1.0 × 10-12M, and the limit of detection (LOD) and limit of quantification (LOQ) for standard solutions werecalculated as 1.29 × 10-14 and 4.29 × 10-14M, respectively. As a result of the study, the developed MIP-based electrochemical sensor was suitable for detecting GAL with high specificity, selectivity, and sensitivity. Recovery studies were performed to determine the practical applicability of the sensor, and the results were satisfactory. This innovative sensor platform stands out as a reliable and sensitive analytical tool for determining GAL.

Bioaccessibility and antioxidant activity of fermented chrysanthemum rice wine on In vitro simulated digestion

The purpose of this study was to investigate the bioaccessibility of total phenolic (TPC), total flavonoid (TFC), chlorogenic acid and antioxidant activity in fermented chrysanthemum rice wine (FRW) under in vitro gastrointestinal digestion model compared with rice wine (RW). The fermented samples were digested and the bioactive components and antioxidant activity during gastric phase (GP) and intestinal phase (IP) were analyzed. The results showed that TPC, TFC, ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) decreased during the gastrointestinal digestion stage. TFC was higher in FRW during in vitro gastrointestinal digestion stage and increased to a maximum of 0.483 mg/mL at IP stage. 2.2- azinobis-3- ethyl-benzothiazoline-6 - sulfonic acid (ABTS) reached its maximum value of 91.62% in the late stage of intestinal digestion. The hydroxyl radical scavenging activity (HRSA) increased to 77.94% in the IP-2 phase. In addition, a total of 158 (FRW) and 131 (RW) polyphenols, including flavonoids, isoflavones, phenols and coumarins, were detected and identified by Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS) analysis. The biotransformation was carried out between the isomers of phenolic compounds in FRW, where 4,5-dicaffeoylquinic acid might be changed into neochlorogenic acid and chlorogenic acid. Correlation analysis showed that 46.15% of metabolites in FRW were positively correlated with the decrease of DPPH, FRAP and ORAC, while 53.85% were positively correlated with the increase of ABTS and HRSA. The results showed higher bioavailability and antioxidative activity in FRW after in vitro digestion.

Modeling the Change in Amino Acid and Peptide Contents during the Aging of Bottled-Fermented Sparkling Wines by Image Processing Methods

In this study, natural sparkling wine was produced using a mixture (1:1) of Emir and Dimrit grapes harvested (Around the Urgup District of Turkey). The change of free amino acid and peptide contents in sparkling wine depending on the aging time and yeasts (free and immobilized forms of the Saccharomyces bayanus and Saccharomyces oviformis) used in the second fermentation stage were examined by image processing methods. The immobilized yeasts were determined as more than the free ones along the second fermentation. It was also determined that the yeast type does not have a significant effect on both the peptides and free amino acid contents of sparkling wines and these contents were divided into 3 classes from high to low by measuring separately along the aging time. The amino acid contents of sparkling wines reached the highest level between the 335th and 365th days of aging time and also exceeded the amino acid contents of base wine.

Quality of jujube wines fermented by different jujube varieties: Physicochemical parameters, antioxidant activity, non-volatile and volatile substances

The varieties of raw materials are significant to the quality of jujube wine. In this study, the physicochemical quality, antioxidant activity, non-volatile and volatile substances of different jujube wines were analyzed. The alcohol content of the different wines ranged from 12.70% (v/v) to 14.19% (v/v). Wine fermented by J60Z showed the highest alcohol content. ZHDZ-fermented wine was the yellowest and its color quality was the best. The main monomeric phenols in date wine are chlorogenic acid, epicatechin and catechin. DZ-fermented wine had the strongest DPPH, ABTS radical scavenging activity and FRAP. The organic acids in date wine were mainly succinic acid, malic acid and lactic acid. JUZ-fermented wine had the highest content of total free amino acids, essential amino acids, and sweet amino acids, which were 817.42, 53.23, and 751.01 mg/L, respectively. Seventy-nine volatile compounds were found in the nineteen jujube wines. Wine fermented by JUZ had the highest total volatiles content (8329.52 mg/L). Principal component analysis and sensory evaluation revealed that DZ-fermented date wine had the highest composite and sensory scores. Therefore, this study showed that DZ was more suitable for making jujube wine. This study provides theoretical guidance for screening suitable varieties for jujube wine fermentation.

Activation of the yeast Retrograde Response pathway by adaptive laboratory evolution with S-(2-aminoethyl)-L-cysteine reduces ethanol and increases glycerol during winemaking

BackgroundGlobal warming causes an increase in the levels of sugars in grapes and hence in ethanol after wine fermentation. Therefore, alcohol reduction is a major target in modern oenology. Deletion of the MKS1 gene, a negative regulator of the Retrograde Response pathway, in Saccharomyces cerevisiae was reported to increase glycerol and reduce ethanol and acetic acid in wine. This study aimed to obtain mutants with a phenotype similar to that of the MKS1 deletion strain by subjecting commercial S. cerevisiae wine strains to an adaptive laboratory evolution (ALE) experiment with the lysine toxic analogue S-(2-aminoethyl)-L-cysteine (AEC).ResultsIn laboratory-scale wine fermentation, isolated AEC-resistant mutants overproduced glycerol and reduced acetic acid. In some cases, ethanol was also reduced. Whole-genome sequencing revealed point mutations in the Retrograde Response activator Rtg2 and in the homocitrate synthases Lys20 and Lys21. However, only mutations in Rtg2 were responsible for the overactivation of the Retrograde Response pathway and ethanol reduction during vinification. Finally, wine fermentation was scaled up in an experimental cellar for one evolved mutant to confirm laboratory-scale results, and any potential negative sensory impact was ruled out.ConclusionsOverall, we have shown that hyperactivation of the Retrograde Response pathway by ALE with AEC is a valid approach for generating ready-to-use mutants with a desirable phenotype in winemaking.

Quantification of lactic acid in wines using an amperometric biosensor

The objective of this study was to develop an analytical method that allows for the rapid and cost-effective detection and quantification of lactic acid in wines. The analysis of lactic acid is a time-consuming and costly process in the food industry. Therefore, the use of an enzymatic amperometric sensor that employs lactate oxidase (LacOx) immobilized on an oxygen electrode enabled the determination of lactic acid in wine. This study utilizes a voltage of −500mV and recorded the amperometric signal was obtained during oxygen consumption while lactic acid oxidation occurred in the sensor reactor. The detection time was at 10 s. A positive linear relationship was obtained between oxygen consumed as a function of time (mg O2/L x s−1). The lactic acid concentration ranged from 1 to 7 mM with a coefficient R2 = 0.994. The sensor exhibited good specificity KM = 0.675. The immobilized enzyme retained over 85% activity for 60 days, allowing for the reuse of the previously modified membrane up to 22 times. In comparison to other methods documented in the literature, the results demonstrate a favourable analytical quality. Furthermore, other aspects, such as the low residual formation, also exhibit a positive outcome. The analysis of lactic acid showed good correlation when compared to HPLC methodology, which occupies the same linear range. This validates the use of the sensor as an alternative method for quantifying lactic acid in wine. The value of this study lies in its presentation of a technique that is more straightforward to implement than traditional methods for quantifying lactic acid in grape wines.

From tyrosine to hydroxytyrosol: a pathway involving biologically active compounds and their determination in wines by ultra performance liquid chromatography with mass spectrometry.

Hydroxytyrosol (HT) is a bioactive compound present in a limited number of foods such as wines, olives, and olive oils. During alcoholic fermentation, yeast converts aromatic amino acids into higher alcohols such as tyrosol, which can undergo hydroxylation into HT. The aim of this study was to validate an analytical method using ultra performance liquid chromatography coupled with mass spectrometry (UPLC/MS-MS) to quantify HT and its precursors (tyrosine, hydroxyphenylpyruvic acid, hydroxyphenylacetaldehyde, 4-hydroxyphenylacetic acid, and tyrosol) in wines. Their occurrence was evaluated in a total of 108 commercial Spanish wine samples. The validated method simultaneously determined both HT and its precursors, with adequatelimits of detection between 0.065 and 21.86 ng mL-1 and quantification limits between 0.199 and 66.27 ng mL-1 in a 5 min run. The concentration of HT in red wines was significantly higher (0.12-2.24 mg L-1) than in white wines (0.01-1.27 mg L-1). The higher the alcoholic degree, the higher was the content of HT. The bioactive 4-hydroxyphenylacetic acid was identified in Spanish wines for the first time at 3.90-127.47 mg L-1, being present in all the samples. The highest HT concentrations were found in red wines and in wines with higher ethanol content. These data are useful for a further estimation of the intake of these bioactive compounds and to enlarge knowledge on chemical composition of wines. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Use of vine-shoots stilbene extract to the reduction of SO2 in red and rosé Italian wine: Effect on phenolic, volatile, and sensory profiles

Sulfur dioxide (SO2) is one of the most used additives in wine industry for its antioxidant and antimicrobial activity. However, due to health concerns, consumers’ demand of wines with either reduced or totally replaced SO2 has increased. This study aimed to assess the effect of partial and total replacement of SO2 with a vine-shoots extract rich in stilbenes in rosé (cv. Sangiovese) and red (cv. Negramaro) wines respectively. Color as well as phenolic, volatile, and sensory profiles of wines were evaluated at bottling and during storage.The results showed that the vine-shoots extract increased the levels of trans-resveratrol, catechin, and gallic acid in wines. Moreover, the positive correlation of procyanidin dimers in red wine suggested an increase of the polymerization reactions. The amount of added extract probably provided lower antimicrobial protection compared to SO2, as indicated by the higher levels of ethyl phenol. The decrease of individual anthocyanins and oxidation aldehydes observed in wines with SO2 replacement and the higher levels of caftaric acid in the rosé wine with the extract suggested a shift of the oxidative protection, with a lower protection towards anthocyanin degradation and higher protection towards carbonyl formation and oxidation of readily oxidizable phenolic acids.

RSM optimization of fermentation technology of yellow wine produced from Millets rice (containing Daylily and Agaricus blazei Murr) and analysis of volatile aroma constituents and amino acid contents by GC–MS and HPLC

The fermentation process was carried out with varied input variables, and all the models showed significant p-values for interaction of variance (<0.05). Millet rice yellow wine with ethanol yield of 15.68%, v/v was produced at an optimized temperature of 32 °C, yeast addition quantity of 9%, and time of 41 days. The volatile compounds in millet rice wine were analyzed by gas chromatography coupled with mass spectrometry (GC/MS). Amino acid components in yellow wines were analyzed by high performance liquid chromatography (HPLC). Ten, twelve and sixteen volatile compounds were detected in wines in fermentation time of 41, 55 and 70 days, respectively. HPLC shows that the content of amino acids in rice wine is not only the highest, but also has 20 kinds, including 8 kinds of essential amino acids for human body. The difference in volatile components and amino acids composition greatly contribute to the flavor of the wine.

Effect of Different Yeasts on the Higher Alcohol Content of Mulberry Wine.

Healthy, nutritious, and delicious mulberry wine is loved by everyone, but there is no specific yeast for mulberry wine. To screen for yeasts with low-yield higher alcohols for the fermentation of mulberry wine, we tested five commonly used commercial yeasts available on the market to ferment mulberry wine. All five yeasts were able to meet the requirements in terms of yeast fermentation capacity, speed, and physical and chemical markers of mulberry wine. The national standards were met by the fermentation requirements and the fermented mulberry wine. We identified yeast DV10 as a yeast with low-yield higher alcohols suitable for mulberry wine fermentation. The total higher alcohol content in fermented mulberry wine was 298 mg/L, which was 41.9% lower than that of fermented mulberry wine with yeast EC118. The contents of 17 free amino acids and five sugars in mulberry juice and five yeast-fermented mulberry wines were tested. The results showed that the higher the amino acid and sugar content in yeast-fermented mulberry wine, the higher the content of higher alcohols produced by fermentation. A correlation analysis performed on each higher alcohol produced when yeast DV10 fermented the mulberry wine indicated decreased sugar and related amino acids. The findings demonstrated a substantial negative correlation among the levels of increased alcohol, decreased sugar, and matching amino acid content. Considering the correlation values among increased alcohol, decreased sugar, and related amino acids, the very slight difference suggests that both sugar anabolism and amino acid catabolism pathways have an equivalent impact on the synthesis of higher alcohols during the fermentation of mulberry wine. These results provide a theoretical basis for reducing the content of higher alcohols in mulberry wines, given the history and foundation for producing mulberry wine.

Chemical and sensory profile of nonconventional white wines from two different grape clones

AbstractThe present study aimed to characterize chemical and sensorial composition of Goethe wines from Goethe Grape's Valley Geographical Indication, Brazil. The wine samples were made from Goethe Clássica grape and its spontaneous clone, Goethe Primo, grown in two different micro‐regions located in the GI territory (2022 and 2023 vintages). Samples were produced by microvinification process and evaluated for classic oenological parameters, antioxidant activity, total polyphenol, organic acids, and sensory descriptive analysis. The results demonstrated that Goethe Clássica wines presented highest browning index, total acidity, antioxidant activity, and total phenolic content in both consecutive vintages. Moreover, in both vintages, the major organic acid in all Goethe wines was malic acid. The wine sensory analysis allowed the accomplishment of the sensorial attributes and its intensities previously unknown in the literature. The overall data afford new insights related to the impact of grape's genetic differences on wine sensorial and chemical characteristics.Practical ApplicationsThis research supports evidence for the relationship between chemical and sensory properties of wine and the sensorial differences in wines due to grape clonal variation. Moreover, the present study detailed the chemical and sensory profiles of wines derived from two different Goethe grape clones, a variety considered nonconventional for winemakers. Overall, the results of this research might be beneficial not only for the producers who are exploring novel or less prevalent wine grape varieties but also to the beverage industry more comprehension through genetic differences influencing wine quality and sensory perceptions.

1H-NMR Spectroscopy Coupled with Chemometrics to Classify Wines According to Different Grape Varieties and Different Terroirs

In this study, 1H-NMR spectroscopy coupled with chemometrics was applied to study the wine metabolome and to classify wines according to different grape varieties and different terroirs. By obtaining the metabolomic fingerprinting and profiling of the wines, it was possible to assess the metabolic biomarkers leading the classification (i.e., phenolic compounds, aroma compounds, amino acids, and organic acids). Moreover, information about the influence of the soil in shaping wine metabolome was obtained. For instance, the relationship between the soil texture and the content of amino acids and organic acids in wines was highlighted. The analysis conducted in this study allowed extraction of relevant spectral information not only from the most populated and concentrated spectral areas (e.g., aliphatic and carbinolic areas), but also from crowded spectral areas held by lowly concentrated compounds (i.e., polyphenols). This may be due to a successful combination between the parameters used for data reduction, preprocessing and elaboration. The metabolomic fingerprinting also allowed exploration of the H-bonds network inside the wines, which affects both gustatory and olfactory perceptions, by modulating the way how solutes interact with the human sensory receptors. These findings may have important implications in the context of food traceability and quality control, providing information about the chemical composition and biomolecular markers from a holistic point of view.

The effect of non-Saccharomyces yeasts on biogenic amines in Sauvignon Blanc wine and Gewürztraminer wine

Biogenic amine (BA) is a class of nitrogen-containing small molecular organic compounds with biological activity. Excessive BAs in wine affect flavor and quality of wine and are hazardous to human health. However, little attention has been paid to the effect of non-Saccharomyces yeasts and Saccharomyces cerevisiae mixed fermentation on BAs in white wine. The effect of mixed fermentation on BAs and amino acids in wine was investigated using two white grapes of Sauvignon Blanc and Gewürztraminer. Higher levels of total amino acids and BAs in Gewürztraminer wine compared to Sauvignon Blanc wine may be due to different grape varieties. Mixed fermentation did not influence BA profiles in Sauvignon Blanc wine, while it increased total BAs content. VL3 (VL) fermented wine has 33.7% less BAs content than EC1118 (EC) single-strain fermented wine. Similar phenomenon was found in Gewürztraminer wine produced by different fermentation combinations except that cadaverine was only detected in wine produced by Hanseniaspora uvarum participated in mixed fermentations. Principal coordinate analysis (PCoA) and permutational multivariate analysis of variance (PERMANOVA) revealed that the effects on BAs were related to grape varieties and yeast species in white wine. Ethanolamine, tryptamine, isoamylamine and histamine content in wine were related to grape varieties. Collectively, mixed fermentation increased BAs content in Sauvignon Blanc and Gewürztraminer wine. The content of BAs in wine fermented by VL single-strain fermentation was lower than that fermented by EC single-strain fermentation, which is more suitable for the winemaking of white wine.

Terahertz SWNT-based fluidic chip for sensing enantioselectivity

Enantioselectivity sensing is crucial in biological systems due to the impact of the selective behaviors of chiral compounds on their targets. Conventional approaches for detecting enantioselectivity are restricted by the presence of high phonon energy, complex device manufacturing processes, low sensitivity, and the need for large sample sizes. Here, we propose a single-walled carbon nanotube (SWNT)-based fluidic chip that uses terahertz (THz) optical rotatory dispersion (ORD) spectroscopy to detect tartaric acids with high selectivity in very small amounts of liquid. The chip is composed of tailored U-shaped metasurfaces that show significant amplification of the near-field around the typical peaks of tartaric acids in the ORD spectrum. Additionally, it includes subwavelength gratings made of SWNTs, allowing for accurate detection of polarization angles. The limit of detection (LOD) for d-tartaric acid and l-tartaric acid are 17.9 mg/L and 11.0 mg/L, respectively. The sensitivities are superior to those of UV ORD or CD spectrometers. Furthermore, the presence of tartaric acid in wine is effectively identified, with a LOD of 25.60 mg/L. This technological development provides a significant improvement in chiral analysis by allowing for quick, highly sensitive, and precise detection of enantiomers.

СОЗДАНИЕ ИНФОРМАЦИОННОЙ БАЗЫ ДАННЫХ ПО КАЧЕСТВЕННЫМ ПОКАЗАТЕЛЯМ ВИНОГРАДА НА ФОНЕ КОМПЛЕКСА АГРОКЛИМАТИЧЕСКИХ ПАРАМЕТРОВ И ИНДЕКСОВ, ХАРАКТЕРИЗУЮЩИХ ТЕПЛООБЕСПЕЧЕННОСТЬ ТЕРРИТОРИИ, ПРИМЕНЯЕМЫХ ДЛЯ ВЫДЕЛЕНИЯ ТЕРРУАРОВ КРЫМА

Climate is one of the main factors determining the possibility of grape cultivating and influencing its growth and development. Climatic factors have a huge impact on obtaining high-quality products of grape processing. In the process of work, in order to create an informational database, the archival data on the content of sugars and titratable acids in grapes from the vineyards of Crimea were collected and systematized. According to the criteria necessary for this study, we have selected the information on 8 varieties from the Steppe zone for 11 years, 1 variety from the Piedmont zone for 3 years, and 4 varieties from the South Coast zone for 6 years. By collecting and nonlinear interpolating of long-term observations from Crimean weather stations using geoinformation and mathematical modeling methods, the values of agroclimatic factors were calculated for each selected vineyard on the dates of determining the quality indicators of grapes during their ripening at the location points of the vineyards. For this purpose, 10 agroclimatic indicators characterizing the heat supply were selected. Based on the research results, basic principles for creating an informational database of agroecological resources and quality composition of grapes were developed. Informational database can be further modified and extended with various agroclimatic indicators. Subsequently, the accumulated array of database information will be used to identify patterns reflecting the influence of agroecological conditions on the formation of grape quality parameters for various types of production, which will serve as a basis for establishing viticultural and winemaking terroirs. Key words: CLIMATIC FACTORS, ZONES OF THE CRIMEAN PENINSULA, HEAT SUPPLY INDICATORS, GEOINFORMATION MODELING, MASS CONCENTRATION OF SUGARS, MASS CONCENTRATION OF TITRATABLE ACIDS

Effects of five different commercial strains of Saccharomyces cerevisiae on the physicochemical parameters, antioxidant activity, phenolic profiles and flavor components of jujube wine

Yeast plays a crucial role in jujube wine fermentation. In this study, the effects of five commercial yeasts on the physicochemical parameters, color, antioxidant properties, phenolic profiles and flavor components of jujube wine were evaluated. The results showed the alcohol content of five wine samples ranged from 12.62% to 13.15%. The colors of the five fermented jujube wine samples were bright yellow-green. Jujube wine samples fermented by BV818 had the best color quality. The total contents of phenolic profiles and free amino acids in wine fermented by BV818 (76.01 mg/L and 110.33 mg/L, respectively) and SY (80.99 mg/L and 121.54 mg/L, respectively) yeasts were significantly higher than those of the other three jujube wine. The free amino acids of wine samples mainly were sweet, and the BV818-fermented wine had the highest content at 56.47%. There were twenty-seven shared aroma substances were found in five samples. The types of volatiles in wine fermented by BV818 and SY were both forty-four, but the former had lower contents of higher alcohols. Sensory score of jujube wine fermented by BV818 was better. Therefore, BV818 was the most suitable yeast for fermenting jujube wine. This study provides a theoretical basis for producing jujube wine.

A consortium of different Saccharomyces species enhances the content of bioactive tryptophan-derived compounds in wine fermentations

In recent years, the presence of molecules derived from aromatic amino acids in wines has been increasingly demonstrated to have a significant influence on wine quality and stability. In addition, interactions between different yeast species have been observed to influence these final properties. In this study, a screening of 81 yeast strains from different environments was carried out to establish a consortium that would promote the improvement of indolic compound levels in wine. Two strains, Saccharomyces uvarum and Saccharomyces eubayanus, with robust fermentative capacity were selected to be combined with a Saccharomyces cerevisiae strain with a predisposition towards the production of indolic compounds. Fermentation dynamics were studied in pure cultures, co-inoculations and sequential inoculations, analysing strain interactions and end-of-fermentation characteristics. Fermentations showing significant interactions were further analyzed for the resulting indolic compounds and aroma profile, with the aim of observing potential interactions and synergies resulting from the combination of different strains in the final wine. Sequential inoculation of S. cerevisiae after S. uvarum or S. eubayanus was observed to increase indolic compound levels, particularly serotonin and 3-indoleacetic acid. This study is the first to demonstrate how the formation of microbial consortia can serve as a useful strategy to enhance compounds with interesting properties in wine, paving the way for future studies and combinations.

Competitive Immunoassay in a Microfluidic Biochip for In-Field Detection of Abscisic Acid in Grapes.

Viticulture and associated products are an important part of the economy in many countries. However, biotic and abiotic stresses impact negatively the production of grapes and wine. Climate change is in many aspects increasing both these stresses. Routine sample retrievals and analysis tend to be time-consuming and require expensive equipment and skilled personnel to operate. These challenges could be overcome through the development of a miniaturized analytic device for early detection of grapevine stresses in the field. Abscisic acid is involved in several plant processes, including the onset of fruit ripening and tolerance mechanisms against drought stress. This hormone can be detected through a competitive immunoassay and is found in plants in concentrations up to 10-1 mg/mL. A microfluidic platform is developed in this work which can detect a minimum of 10-11 mg/mL of abscisic acid in buffer. Grape samples were tested using the microfluidic system alongside benchmark techniques such as high-performance liquid chromatography. The microfluidic system could detect the increase to 10-5 mg/mL of abscisic acid present in real berry samples at the veraison stage of ripening.