Search Results (250)

Climate change poses a major challenge for wine production in semi-arid regions, where grape ripening frequently leads to excessive sugar accumulation and reduced acidity. This study evaluated the combined effect of cold pre-fermentative maceration (PM) and the use of non-Saccharomyces yeasts (Lachancea thermotolerans and Torulaspora delbrueckii) on the composition and sensory properties of Cayetana Blanca wines. Pre-fermentative maceration increased titratable acidity by 0.5 g/L and yeast-assimilable nitrogen by 28 mg/L, creating more favorable conditions for the metabolic activity of non-Saccharomyces species. Wines fermented with L. thermotolerans—especially in sequential inoculation with S. cerevisiae after PM—showed the highest acidity and lactic acid content (2 g/L), together with 1% v/v lower ethanol and 1 g/L higher glycerol than the control. These wines were perceived as fresher and better balanced, despite a moderate decrease in fruity esters such as ethyl hexanoate, ethyl octanoate, and isoamyl acetate. Cluster analysis confirmed that non-Saccharomyces fermentations developed distinct compositional profiles only when combined with PM. Overall, the PM + L. thermotolerans + S. cerevisiae treatment achieved the most favorable balance between acidity, ethanol, and sensory freshness. This approach provides a sustainable and readily applicable method to enhance acidity and freshness in white wines from warm-climate regions. Full article

Some special volatile organic compounds (VOCs) that significantly induce female oviposition preferences may be utilized to disrupt oviposition behavior and to enhance trapping strategies; such approaches offer a promising avenue for reducing insect infestations in stored commodities. Based on the significant differences in the oviposition preference of P. interpunctella among six normal-oleic varieties (NOPs), the key VOCs involved were further explored. Seventeen VOCs that may contribute the oviposition preference and that exhibited a high content in the peanut varieties were measured through electroantennogram (EAG) response measurements of female moths. The VOCs that produced significant EAG responses by the females were further assayed for behavioral responses by the Y-tube olfactometer method, wind tunnel tests, and a multiple-choice device for female oviposition. Heptanal, acetophenone, nonanal, hexanal, benzaldehyde, octanal, hexanoic acid, decanal, phenylacetaldehyde, and 1-octen-3-ol from peanuts elicited strong antennal EAG responses. These VOCs (especially heptanal, nonanal, hexanal, octanal, and decanal) attracted more females in both Y-tube olfactometer and wind tunnel assays and increased oviposition rates in oviposition tests. The results indicate that heptanal, decanal, octanal, nonanal, and hexanal may be utilized to develop oviposition attractants for female moths further. Full article

This study reports on the direct electron transfer (DET) ability of the enzyme spermidine dehydrogenase (SpDH) and its use in a DET-type enzymatic sensor for detecting spermine. SpDH was found to exhibit internal electron transfer from its cofactor, flavin adenine dinucleotide (FAD), to heme b. This was confirmed by observing the heme b-derived reduction peak at 560 nm in the presence of spermine, the substrate. SpDH was immobilized on a gold electrode via a dithiobis (succinimidyl hexanoate) self-assembled monolayer. The cyclic voltammetry analysis of the SpDH-immobilized gold electrode revealed an increased oxidation current in the presence of 0.1 mM spermine with an onset potential of −0.14 V vs. Ag/AgCl in the absence of an additional external electron acceptor. This result confirmed that SpDH is capable of DET. Chronoamperometric analyses were conducted using an SpDH-immobilized gold electrode with spermine as the substrate under a 0 V oxidation potential vs. Ag/AgCl using an artificial saliva matrix containing 10 µM ascorbic acid and 100 µM uric acid. The sensor exhibited good linear correlation between the current increase and spermine concentration from 0.2 to 2.0 µM, with a limit of detection of 0.084 µM, which encompasses the physiologically relevant spermine concentration found in the saliva. Primary structure alignments and 3D structure predictions revealed that all SpDH homologs possess two conserved histidine residues in the same location on the surface as the heme b ligand of SpDH. This indicates their potential for DET-ability with an electrode. Full article

Pre-fermentative treatments are essential in winemaking, as they significantly influence the quality and stability of white wines in particular. The synthesis of many compounds obtained from yeast, such as higher alcohols and esters, is influenced by the type and concentration of aromatic precursors present in the must, especially amino acids. Clarification has a positive effect on wine quality, mainly by improving organoleptic properties, with flavour being the most affected. In this study, the influences of different static settling times, different pressures during must extraction and the addition of different bentonite concentrations to the must on the aroma of wines from the autochthonous grape varieties Krstač and Žižak were investigated. The identification of aromatic compounds in the wine was performed using GC/FID-MS analysis. Wine subjected to the longest static settling time (30 h) showed the highest concentration of esters. Krstač wine, which underwent a 30 h of settling, was characterised by an increased concentration of esters, such as isoamyl acetate, ethyl decanoate and ethyl hexanoate, while Žižak wine was characterised by the presence of 2-phenylethyl acetate and isoamyl acetate. The total fatty acid content in Krstač wine obtained by pressing was higher (14.90 mg/L) than in wine produced from free-run juice (8.04 mg/L). Full article

Background: Amyotrophic lateral sclerosis (ALS) evolution is influenced by many dietary factors, biochemical and hormonal inter-relations and gut microbiota. This study focuses on dynamics by conducting a plasmatic quantitative analysis of six of the main short-chain fatty acids (SCFAs) for ALS patients and the shifts in circulating SCFA profiles during ALS progression as well as their potential responsiveness or change due to dietary modulation. Methods: A 12-month prospective study in parallel with control group determinations was conducted. The patients diagnosed with ALS were evaluated at the start of the study (T0) followed by a six-month observation time frame (T1) and after another six months of a Mediterranean diet intervention (T2). Plasma SCFAs were determined using liquid chromatography coupled to mass spectrometry to showcase the plasmatic profiles. Correlation between plasma levels of SCFAs and patients’ clinical characteristics next to correlations between plasma SCFA levels at T1 and T2 were performed. Results: A significant increase between control group and patients at T0 was observed for acetic, propionic, butyric and hydroxy-butyric acid. Hexanoic acid levels stagnated and 4-methyl-valeric acid concentrations decreased. Evolutions from T1 and T2 impacted acetate, propionate and 4-methyl-valerate. Conclusions: The study offers a better understanding regarding the differences in SCFA levels in ALS patients. The Mediterranean diet may impact the levels of acetic and propionic acid, indicating the modulation of SCFA production by gut microbiota. Full article

Background: Lophatheri Herba, a traditional East Asian herb with documented food uses, contains bioactive flavonoids. This study investigated how Aspergillus oryzae fermentation modifies its short-chain fatty acids (SCFAs) and metabolome, and evaluated the fermented product’s impact on intestinal barrier function in mice. Methods: Fermented leaf extracts were analyzed via GC-MS/LC-MS for SCFAs and metabolites. Forty-eight mice were divided into control (standard diet) and three experimental groups (25, 50, 100 mg/kg/day fermented product). After a 4-week intervention, duodenal morphology, colonic cytokines (IL-6/IL-1β), and cecal microbiota were assessed. Results: We identified significant SCFAs optimization. Significantly increased: acetic acid; butyric acid (p < 0.001); isobutyric acid (p < 0.01); isovaleric acid (p < 0.05). No significant change: propionic acid and isohexanoic acid. Significantly decreased: valeric acid and hexanoic acid (p < 0.001). Metabolomic remodeling showed (i) flavonoid pathway activation and (ii) key metabolite upregulation (daidzein, 4,7-dihydroxyflavone, 3,7-dimethylquercetin, aloe-emodin, soyasapogenol M1, etc.). Gut function peaked at 100 mg/kg with 18% higher duodenal villus height (p < 0.05), improved villus/crypt ratio, and reduced IL-6/IL-1β. Probiotic taxa including Lactobacillus, unclassified f__Lachnospiraceae, Dubosiella, and Monoglobus increased. Conclusions: Fermented Lophatheri Herba protects gut health through synergistic SCFAs optimization, flavonoid enrichment, and probiotic proliferation, supporting its potential as a microbiota-targeting functional food ingredient. Full article

Upcycling, or utilizing materials that would otherwise go to waste, enables the creation of novel products that offer sustainability advantages and generate additional value. This study evaluates the feasibility of producing alcoholic beverages using yogurt acid whey (YAW) and grape pomace (GP), byproducts of the dairy and wine industries, respectively, and compares them to commercial grape pomace beverages (piquettes) in terms of sensory attributes and chemical composition. Two YAW-GP piquettes were produced, and five commercial piquettes were obtained. Sugars and organic acids were quantified using HPLC-RID, and semi-quantitative volatile composition was determined using HS-SPME-GC-MS/MS. Descriptive analysis was conducted using a trained panel of 11 individuals. The YAW products had higher ratings for dairy, salty, acidic, and umami attributes, and lower ratings for bitterness, sweetness, red fruit, dried fruit, and overall fruity characteristics. YAW beverages were higher in titratable acidity (TA), lactose, lactic acid, citric acid, galactose, hexanoic acid, 3-methylpentanol, 1-octanol, and 1-octen-3-ol, and lower in ethanol and linalool. The commercial products were differentiated based on ethanol content, red fruit, dried fruit, fruitiness, chemical, and barnyard aromas. These results can be used to understand the breadth of chemical and organoleptic signatures of this new beverage category, which can be leveraged by stakeholders interested in entering the market. Full article

Temporal lobe epilepsy (TLE) remains pharmacoresistant in 30–40% of patients. Peroxisome proliferator-activated receptor alpha (PPARα) agonists like fenofibrate exhibit anti-inflammatory and neuroprotective properties, but their region-specific effects during epileptogenesis and on behavioral comorbidities are unknown. We investigated fenofibrate (100 mg/kg, 7 days) in the lithium-pilocarpine rat model during the latent phase. Fenofibrate (1) reduced anxiety-like behaviors and improved exploratory deficits; (2) decreased plasma short-chain fatty acids (butyric, pentanoic, hexanoic acids); (3) exerted region-specific modulation of glutamate receptors: restored N-methyl-D-aspartate receptor (NMDAR)/α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit gene expression in temporal cortex but failed to reverse and further exacerbated the downregulation of AMPAR subunits in the dorsal hippocampus; (4) prevented the upregulation of cortical neuroinflammation markers (reduced Nlrp3, Il1rn); and (5) enhanced the A2 astrocyte marker Ptx3 in the hippocampus while reducing the M2 microglial marker Arg1 in the temporal cortex. No effects on astrogliosis (Gfap), microgliosis (Aif1), or trophic factors (Bdnf, Tgfb1) were observed. This first comprehensive study demonstrates that fenofibrate differentially modulates neuroinflammation and synaptic plasticity across brain regions during epileptogenesis, providing behavioral benefits but highlighting potential hippocampal drawbacks. Its PPARα-mediated actions support further investigation as a complementary strategy for TLE, pending optimization of dosing/timing to mitigate regional disparities. Full article

Ageing in oak barrels affects the tertiary aroma of red wine, yet further research on the impact of different conditions used for medium toasting of barrels could still be conducted to optimise wine production and meet consumer preferences. In this study, using the GC/MS method, the aroma profiles of two consecutive vintages of Cabernet Sauvignon wine and samples aged for 12 months in different vessels were determined. Besides the stainless steel tanks, Excellence barrels with medium, medium plus, and medium long toasting, and Premium barrels with medium toasting were used. A total of 48 aroma compounds were identified, and their odour activity value (OAV ≥ 1) was calculated. According to it, 10 key compounds were selected: β-damascenone, ethyl octanoate, ethyl vanillate, ethyl cinnamate, lauric acid, linalool, hotrienol, ethyl hexanoate, diethyl succinate, and 2-phenylethanol. The results showed that wooden barrels have a greater impact on wine aroma during ageing, compared to stainless steel tanks. The initial wine aroma and key compounds with fruity, floral, and fatty notes were most preserved in the stainless steel tank. The study highlights that controlled selection of barrel type (grain density) and toasting method can significantly modulate the aromatic complexity of Cabernet Sauvignon wines. Toasted barrels resulted in an increase in smoky and woody notes (volatile phenols and lactones), and a decrease in fruity and floral notes (β-damascenone, 2-phenylethanol, hotrienol, linalool, etc.). These findings could provide practical guidelines for winemakers for optimising ageing strategies and contributing new insights into the impact of wine vessels on aroma development and sensory perception. Full article

This study explores the chemical and sensory differentiation of Greek white wines produced from five indigenous grape varieties—Savvatiano, Vidiano, Moschofilero, Assyrtiko, and Malagouzia—across diverse terroirs in Greece. A targeted analytical approach was employed to quantify 12 key volatile aroma compounds derived primarily from amino acid metabolism and lipid degradation, using GC-MS and GC-FID. The selected volatiles, including isoamyl alcohol, phenylethyl alcohol, tyrosol, and hexanoic acid ethyl ester, were chosen for their sensory relevance and their biosynthetic linkage to nitrogenous precursors. Principal Component Analysis (PCA) of wines from the 2019 and 2020 vintages revealed clear varietal clustering, under standardized winemaking conditions. Malagouzia wines were characterized by rich and diverse volatile profiles, particularly long-chain fatty acids and esters, while Vidiano exhibited a consistently restrained aromatic expression. Sensory analysis using sorting and ultra-flash profiling confirmed the chemical clustering, with Moschofilero, Vidiano and Malagouzia wines forming distinct sensory groups. The findings demonstrate that key amino acid-derived volatiles can serve as biochemical markers of varietal typicity and support the use of volatile profiling as a tool for terroir-driven wine classification and quality assessment in Greek white wines. Full article

Syngas fermentation in combination with chain elongation offers great promise for sustainable medium-chain fatty acid production. While immobilization has proven effective for stabilizing monocultures of C. kluyveri for chain elongation, its applicability to co-cultures involving C. carboxidivorans for simultaneous syngas fermentation remains unexplored. This study investigates the physiological compatibility of C. carboxidivorans with agar-based hydrogel immobilization and its co-cultivation potential with C. kluyveri in a synthetic dual-layer biofilm reactor. First, we conducted autotrophic batch fermentations using suspended and immobilized cells, proving metabolic activity similar for both. Applying different sulfur feeding rates, experiments showed best ethanol formation with C. carboxidivorans at increased sulfur feeding, enabling better conditions for chain elongation with C. kluyveri. In the synthetic dual-layer biofilm reactor, with the C. carboxidivorans biofilm in contact with the CO-containing gas phase above the C. kluyveri biofilm, the formation of 1-butyrate and 1-hexanoate was observed with product formation rates of 0.46 g L⁻¹ d⁻¹ 1-butyrate, and 0.91 g L⁻¹ d⁻¹ 1-hexanoate, respectively. The formation rate of 1-hexanoate in the dual-layer biofilm reactor was approximately 7.6 times higher than that reported with suspended cells in a stirred tank bioreactor. Spatial analysis revealed species-specific migration behavior and confirmed that C. carboxidivorans reduced local CO concentrations, improving the environment for C. kluyveri. Full article

Background: Overweight and obesity are currently a worldwide problem, with undesirable health consequences, such as type 2 diabetes. Therefore, much attention has been paid to preventing obesity through diet. Free fatty acids (FFAs) serve as signaling molecules in many biological processes, leading to increased energy expenditure and insulin secretion. Short-chain fatty acids (SCFAs) such as acetic, propionic and butyric acid are bioactive metabolites produced by gut microbes, and their beneficial effects on host metabolism are well studied. However, the effects of hexanoic acid on metabolism are poorly understood. Methods: Male C57BL/6J mice were fed a normal chow diet, a high-fat diet (HFD), an HFD containing 5% butyric acid or an HFD containing 5% hexanoic acid for 4 weeks, and the effects of hexanoic acid on their lipid and glucose metabolisms were examined. Results: Dietary supplementation of hexanoic acid or butyric acid for 4 weeks prevented HFD-induced obesity and fat accumulation in the white adipose tissues. Both FFAs also suppressed the elevated plasma non-esterified fatty acid (NEFA) levels and hepatic triglyceride content in the mice fed an HFD. In addition, butyric acid and hexanoic acid decreased the elevated expression of genes involved in fatty acid biosynthesis in the white adipose tissues under HFD conditions. Hyperinsulinemia induced by HFD feeding was attenuated by oral intake of butyric acid or hexanoic acid, whereas hyperglycemia under HFD feeding was improved only through oral administration of hexanoic acid. Hexanoic acid increased plasma glucagon-like peptide-1 (GLP-1) levels and the expression of genes associated with gluconeogenesis. The intraperitoneal glucose tolerance test (IPGTT) and the insulin tolerance test (ITT) revealed that the oral administration of hexanoic acid significantly enhanced glucose tolerance and insulin sensitivity. Conclusions: This study highlights the importance of hexanoic acid in improving lipid and glucose metabolisms. Hexanoic acid, as well as butyric acid, is a remarkable FFA with anti-obesity properties. Furthermore, hexanoic acid is more potent in maintaining glucose homeostasis than butyric acid. Thus, our findings provide insight into the development of functional foods which could prevent obesity-related diseases such as type 2 diabetes. Full article

The most notable effects of climate change on wine production are higher alcohol levels, lower acidity and changes to the regions suitable for growing grapes. One solution to acidity problems is the use of Lachancea thermotolerans, a yeast that produces lactic acid during fermentation, albeit at the cost of reduced aromatic complexity. A novel approach to addressing this problem is to use L. thermotolerans to produce wines with a very high acidity, regardless of other parameters, for subsequent blending with a control wine with a naturally low acidity. This achieves a balanced acidity while retaining the organoleptic characteristics of the control wine. This is a novel idea, as L. thermotolerans is not usually used in the final wine. However, the objective from the beginning is to create a blend that combines the best characteristics of the control wine with the improved acidity provided by L. thermotolerans. Base wines were produced by inoculating Saccharomyces cerevisiae 20, 40, or 60 h after inoculating L. thermotolerans. Base wines generally show an increase in lactic acid content and a decrease in certain key aromatic compounds, such as isoamyl acetate, 2-phenylethyl acetate, ethyl hexanoate, and ethyl octanoate. Concentrations of other compounds such as acetaldehyde and higher alcohols also increase. The base wines were then blended with a low-acidity control wine. The resulting blends exhibited higher acidity than the control wine, as well as better aromatic profiles, particularly regarding fruity and green fruit aromatic compounds, compared to base wines. Ten volatile compounds have been correlated with lactic acid production by L. thermotolerans, namely ethyl hexanoate; ethyl butanoate; 2-methylbutanol; ethyl heptanoate; isoamyl acetate; acetaldehyde; isobutanol; 2-phenylethanol; dodecanol; and acetoin. The first five are negatively correlated and the rest are positively correlated. Lastly, sensory analysis revealed that the blends achieved the best balance between acidity and aroma, making them the most popular with tasters. Full article

To investigate the effect of Botrytis cinerea infection severity on the flavor characteristics of Petit Manseng noble rot wine, this study analyzed wines produced from Petit Manseng grapes grown in the eastern foothills of Helan Mountain, Ningxia, China. The grapes were categorized into three groups based on infection status: uninfected, mildly infected, and severely infected with Botrytis cinerea. Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and an electronic nose were employed to detect and analyze the aroma components of wines under the three infection conditions. Additionally, trained sensory panelists conducted sensory evaluations of the wine aromas. The results revealed that wines made from severely infected grapes exhibited the richest and most complex aroma profiles. A total of 70 volatile compounds were identified, comprising 32 esters, 17 alcohols, 5 acids, 8 aldehydes and ketones, 4 terpenes, and 4 other compounds. Among these, esters and alcohols accounted for the highest contents. Key aroma-active compounds included isoamyl acetate, ethyl decanoate, phenethyl acetate, ethyl laurate, hexanoic acid, linalool, decanoic acid, citronellol, ethyl hexanoate, and methyl octanoate. Sensory evaluation indicated that the “floral aroma”, “pineapple/banana aroma”, “honey aroma”, and “overall aroma intensity” were most pronounced in the severely infected group. These findings provide theoretical support for the harvesting of severely Botrytis cinerea-infected Petit Manseng grapes and the production of high-quality noble rot wine in this region. Full article

The impact of seasonality on the aroma quality of tea has been documented in various tea types, but not specifically in oolong tea. This study is the first to explore the complex relationships between seasonality, volatile compounds, and aroma quality in oolong tea. Using Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS)-based untargeted metabolomics, we analyzed 266 samples of Tieguanyin oolong tea. The data identified linalool, linalool oxides (trans-linalool oxide (furanoid) and trans-linalool oxide (pyranoid)), and their metabolites (diendiol I; hotrienol) as key seasonal discriminants. Four out of the top ten key differential compounds for distinguishing aroma scores were metabolites from fatty acid degradation, namely trans-3-hexenyl butyrate, trans-2-hexenyl hexanoate, hexyl hexanoate, and hexyl 2-methyl butyrate. Approximately one-fifth of the seasonal discriminant volatile compounds were significant in influencing aroma quality. Overall, the impact of seasonality on the aroma quality of finished Tieguanyin oolong tea is marginal. These findings enhance our understanding of the interplay between seasonal variations, volatile composition, and aroma quality in oolong tea. Full article