Search Results (791)

Seasonal variation in aroma quality is critical for commercial grading of Xinyang Maojian (XYMJ) green tea, and how seasonal changes shape its volatile composition and aroma profile remains unclear. This study investigated the volatile profiles of XYMJ harvested in spring, summer, and autumn using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and odor activity value (OAV) analysis. A total of 93 volatile compounds were identified, with alkenes, alcohols, and esters being the most numerous chemical classes. Total volatile content decreased significantly seasonally (p < 0.05), being highest in spring (1716.68 μg/kg), followed by summer (1566.72 μg/kg) and autumn (1378.21 μg/kg). PCA and PLS-DA clearly distinguished seasons. Using a dual-filtering strategy (variable importance in the projection > 1.0 and p < 0.01), 14 differential volatile metabolites were identified as core seasonal markers. Geraniol, cis-jasmone, and indole were identified as key drivers of the premium floral fragrance in spring XYMJ, while cis-3-hexenyl hexanoate and linalool peaked in the summer harvest. OAV results and cross-modal sensory interaction principles suggest that the superior flavor of spring XYMJ arises from both higher aromatic intensity and an optimized aroma-taste balance. These findings provide useful insights into the seasonal variations in the metabolic and chemical profiles of XYMJ, enhancing our understanding of the biochemical markers associated with its production timeline. Full article

The primary factor in the formation of polycyclic aromatic hydrocarbons (PAHs) in diesel engines, which pose environmental and health risks, is the chemical composition of the diesel fuel. Higher-carbon alcohols have emerged as promising oxygenated blending components for compression ignition engines due to their potential to improve combustion and reduce harmful emissions. However, limited data exist regarding their impact on PAH formation and toxicity characteristics. This study investigates the effects of 15% (v/v) n-propanol, n-butanol, and n-pentanol blends with petroleum diesel (D) and waste cooking oil biodiesel (B) on total PAH emissions, PAH dispersion, and toxicity in a diesel engine under steady-state conditions. Total PAH concentrations and individual species distributions were quantified, and toxicity was evaluated using toxicity equivalency factor (TEF) methodology. Results indicate that the addition of higher alcohols significantly reduces total PAH emissions compared to the respective base fuels. A marked decrease in high-molecular-weight (4–6 ring) PAH compounds was observed, suggesting suppression of heavy PAH formation pathways. Toxicity-weighted PAH emissions also decreased with alcohol blending. Furthermore, total PAH concentrations for all tested blends remained below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL = 0.2 mg/m³) under the examined operating conditions. These findings demonstrate that 15% higher alcohol blends are effective in mitigating PAH emissions without adverse environmental health implications. Full article

Yeasts are among the intrinsic factors affecting the quality of beer due to their impact on flavor. Apart from a long and rich brewing tradition of natural fermentations, involving different yeast and bacterial species in regions such as Belgium, non-Saccharomyces yeasts have not been the preferred industrial inoculation strains in both winemaking and brewing sectors. This is mainly due to their slower fermentation rates, lower alcohol tolerance, and limited ability to complete fermentation. This review explores the brewing characteristics of Torulaspora delbrueckii strains, focusing on the aromatic profile of the produced beers, in comparison with the well-known Saccharomyces cerevisiae brewing strains. The effect of fermentation parameters, as well as the use of mono- and mixed cultures with S. cerevisiae, is discussed. Specific T. delbrueckii strains have demonstrated the ability to ferment wort sugars and produce alcohol levels of up to 4–6% (v/v). The main volatile compounds produced include higher alcohols, such as isoamyl and phenyl ethyl alcohol, as well as esters and their acid precursors. Among these, ethyl hexanoate and ethyl octanoate are particularly important due to their contribution to fruity aromas. Mixed fermentations involving T. delbrueckii and S. cerevisiae have been shown to enhance ester production, resulting in improved aromatic complexity in the final product. Full article

Magnolia cavaleriei var. platypetala ‘Tanchun’ is a newly registered flower variety in China, known for its characteristic floral aroma that intensifies toward full bloom. However, the composition of the volatiles of this aromatic flower remains uncharacterized. Here, we compared the volatile organic compound composition of Tanchun through gas chromatography–mass spectrometry and comparative transcriptome sequencing analyses of the stamen (S), pistil (P), and petals (T) during flower development, i.e., the bud (S1), semi-opened (S2), and bloom (S3) stages. We present a first comprehensive profile of 1395 metabolites from Tanchun’s floral organs. Terpenoids (26.2%) constituted the largest chemical group, followed by esters (17.52%), nitrogen compounds (9.83%), hydrocarbons (8.11%), alcohols (7.97%), aldehydes (6.53%), and others. We found that volatile organic compound (VOC) accumulation was both spatiotemporal and stage-specific. The S1 and S2 transition was characterized by scent notes of green, herbal, and waxy aromas, while the S2 and S3 shift exhibited a richer profile of fruity, sweet, and creamy notes, primarily in petals. A comparative VOC and transcriptomic analysis revealed that petals activate pathways for structural expansion and precursor mobilization, stamens enhance lipid and terpenoid metabolism, and pistils maintain a conserved profile. Importantly, the S1 and S2 transition in petals establishes the biochemical foundation by activating acyl-CoA, phenylpropanoid, and terpenoid synthesis pathways, which enables the activation of the butanoate metabolism pathway at S3, leading to the production of ester-rich compounds that define the floral scent. The transition to full bloom involves a shift to energy-efficient volatile biosynthesis, supported by carbohydrate restructuring and phytohormonal regulation. Our results provide the first comprehensive volatilome and transcriptome resource for ‘Tanchun’, revealing a highly efficient, multi-stage strategy for floral fragrance biosynthesis. This work lays a molecular foundation for future horticultural improvement and biotechnological applications in the flavor and fragrance industries. Full article

2-Phenylethanol (2-PE) is a key aromatic alcohol contributing to the rose-like odor in brewed wines, primarily synthesized by yeast metabolism with a typical yield of less than 100 mg/L. To enhance the 2-PE content in brewed wines, this study used CRISPR-Cas9 gene editing technology to delete the ARO8 gene (encoding aromatic transaminase I) in Saccharomyces cerevisiae SY. The single-factor experiments were performed to optimize the fermentation process, and the 2-PE content in the brewed wine was measured by high-performance liquid chromatography. The results demonstrated that the 2-PE content in whisky fermented by the SY-A8 was 0.73 g/L, increasing 23.73% compared to SY. The fermentation conditions of SY-A8 were optimized through single-factor experiments and the Box–Behnken design. The optimal conditions were a sugar concentration of 46.30 g/L, a fermentation time of 6 days, and an L-phenylalanine concentration of 1.43 g/L. The high 2-phenylethanol aroma whisky was brewed with a higher 2-phenylethanol content of 3.68 g/L in a 1 L fermenter at the optimal conditions. In conclusion, the modification of Saccharomyces cerevisiae by CRISPR-Cas9 gene editing combined with fermentation process optimization provides an effective technical strategy for improving the 2-PE content in whisky, thereby providing a research perspective for the flavor enhancement of whisky and other brewed wines. Full article

Because of the rising occurrence of extremely hot summers linked to climate change, there is a mass appearance of heat-damaged fruits of ‘Čačanska Lepotica’, which are unsuitable for fresh consumption and processing into products in which the fruits’ appearance is a critical quality attribute. To address this issue, the aim of the study was to examine the possibility of producing plum spirits from such fruits as one of the potential ways to utilize them. Heat-damaged fruits were processed in nine different ways, including a traditional one. All produced plum spirits met legal requirements. GC-MS analysis of 39 volatile compounds revealed that the plum spirits made from heat-damaged fruits had different aromatic profiles depending on the processing method applied. However, the plum spirit produced in the traditional way had various sensory defects; the most notable were a lack of freshness and a distinctly unpleasant ‘cooked plum’ aroma. Modifications to the production method led to an improvement in the sensory characteristics of the plum spirits. The obtained results indicate that modifications in small distilleries should include fruit crushing, stone removal and usage of baker’s yeast. In large distilleries, though, the best sensory characteristics for plum spirits made from heat-damaged fruits could be obtained using a production method that includes fruit pulping with stone removal and spontaneous alcoholic fermentation, with one additional step: lowering the pH of the mash before alcoholic fermentation to 3.0. Full article

This study evaluates the impact of the complete early leaf removal on the fruit zone for consecutive growing seasons (2023–2024) on the agronomic performance and oenological potential of the indigenous Greek red cultivar Avgoustiatis (Vitis vinifera L.), which is cultivated in Zakynthos, Greece. The defoliated treatment significantly reconfigured vine productivity, inducing a 33–34% reduction in yield during both years of the study and a contraction in berry mass, which consequently increased the skin-to-berry ratio by 30% and 60% for the 2023 and 2024 vintages, respectively. In the must, defoliation facilitated a desirable decoupling of sugar and acidity, achieving higher soluble solids while maintaining a robust acid core. Furthermore, defoliation enhanced phenolic maturity, in both vintages, increasing total anthocyanins and improving their extractability. Although extreme thermal conditions in 2024 led to lower color intensity and total phenolics in the treated wines compared to the control, the volatile profile revealed a significant reduction in herbaceous C₆ alcohols and an increase in floral terpenes like nerol. Sensory analysis confirmed that defoliated wines were characterized by lower astringency and superior aromatic typicity, with distinct notes of violet and vanilla. These findings suggest that early defoliation is a potent tool for optimizing the structural and aromatic integrity of Avgoustiatis, though its application must be adapted against Mediterranean thermal stress. Full article

Zwitterionic ion-exchange polymers, known for advanced sorption properties, were used in this study to investigate their impact on the phenolic and volatile aroma compounds of Fetească neagră (FN) and Cabernet Sauvignon (CS) wines. Treatments with these compounds showed decreases in total phenolic content from 7.08 to 5.79 g/L gallic acid equivalents (GAE) in CS and from 5.96 to 4.76 g/L GAE in FN, reducing tannins and reactive phenolics and enhancing colloidal stability. Analysis of volatile compounds revealed selective increases in key esters and higher alcohols, contributing to enhanced fruity notes reaching 22.9% in CS and 26.8% in FN, and floral notes reaching 14.9% in CS and 20.4% in FN. Principal component analysis (PCA) showed clear separation by variety (PC1: 54.8%) and treatment (PC2: 30.1%), while heatmap clustering highlighted variety-specific volatile profiles. These results demonstrate that zwitterionic resin treatment represents a novel approach for controlled modulation of wine composition and aroma, enhancing stability and aromatic complexity while preserving varietal typicity. Full article

Yeast selection plays a strategic role in winemaking, influencing not only the quality and style of the final product but also the expression of the cultivar. This study evaluated the impact of selected Saccharomyces cerevisiae strains on the fermentation of three white grape cultivars grown in Western Sicily: Grillo, Catarratto, and Moscato Giallo (Vitis vinifera L.). A standardized vinification protocol was applied to assess the fermentative performance and effects on the chemical composition, aromatic profile, and sensory profile. Alcoholic fermentation kinetics, major analytical parameters, free and glycosylated volatile compounds, and sensory attributes were monitored. Significant differences were observed among the yeast strains in their fermentation dynamics and production of secondary metabolites. Notably, certain strains enhanced the aromatic expressions of the cultivars, particularly in Moscato Giallo, modulating the free and glycosylated terpene profiles. This approach to fermentation highlights the potential to optimize wine quality through yeast selection, aligning the strain performance with the specific needs of each cultivar. Furthermore, the use of efficient yeast strains may reduce reliance on additives, contributing to more sustainable and economically viable winemaking. Full article

Background: Cigarette smoking exposes the human body to a complex mixture of toxic and carcinogenic compounds that can exert widespread biological effects across different organ systems. From addictive responses and consequence maladaptive neuroendocrine responses, cigarette smoke delivers a variety of reactive oxygen species, polycyclic aromatic hydrocarbons, nitrosamines, and heavy metals that collectively contribute to oxidative stress, inflammation, endothelial dysfunction, and metabolic disruption. The liver, as the primary organ responsible for xenobiotic metabolism, plays a central role in processing these harmful substances and is therefore uniquely susceptible to their effects. This narrative review will aim to provide an overview of the current evidence of cigarette smoking effects on hepatic structure and function and discuss clinical implications. Methods: This narrative review synthesizes evidence from in vitro studies, animal models, and human clinical research examining the effects of cigarette smoking on liver biology. Mechanistic pathways of injury, metabolic and vascular alterations, and clinical consequences for liver disease were considered. Results: Smoking influences hepatic function both directly—through biotransformation pathways generating reactive intermediates—and indirectly via vascular impairment, immune modulation, hormonal alterations, and changes in lipid and glucose metabolism. Emerging evidence indicates that cigarette smoking contributes to hepatic steatosis, accelerates fibrosis progression, worsens outcomes in viral and alcohol-related liver disease, and increases the risk of hepatocellular carcinoma. Conclusions: Cigarette smoking exerts multifaceted deleterious effects on the liver. Recognition of smoking as a modifiable risk factor for liver-related morbidity underscores the importance of smoking cessation in patients with or at risk for liver disease and highlights implications for research and clinical practice. Full article

Wood is a material frequently used in the production of alcoholic beverages. Oak barrels have been used to store wines, beers, and spirits for generations. Nowadays, beverages are increasingly matured in the presence of staves and chips from various wood species. The aim of this article was to describe the impact of different wood species and their thermal processing conditions on the quality of alcoholic beverages. The article describes the chemical composition of wood and the compounds formed during toasting at various temperatures. It also lists the volatile compounds extracted from wood for alcoholic beverages, along with their sensory thresholds and their impact on olfactory sensations. Attention was drawn to potentially harmful substances formed during wood toasting, including aromatic hydrocarbons and polycyclic aromatic hydrocarbons. The amounts of compounds extracted from wines, beers, and spirits from different wood species and toasted under different conditions were compared. Quercus barrels contribute to higher lactone concentrations in beverages, which have a coconut aroma. Cherry, acacia, and ash wood increase the concentration of volatile phenols in beverages. The use of staves and chips shortens the maturation time and facilitates the design of beverages with specific sensory characteristics. Full article

The aim of this study was to develop and characterize a wine-based flavored beverage produced from single-varietal white Moscatel wine with the incorporation of freeze-dried strawberry extract (cv. Fortuna Original^®), and to evaluate its physicochemical, chromatic, and short-term sensory stability over 20 days. Five formulations (0, 4, 6, 8, and 12 g extract per 500 mL) were analyzed after 10 and 20 days of storage. The incorporation of strawberry extract led to increased total acidity and slight dilution of alcohol content (from ≈7.1% to 6.9% v/v), while pH and density remained stable, indicating the preservation of the physicochemical structure of the wine matrix. Chromatic parameters showed modulation associated with strawberry-derived pigments, with reduced variability over time, suggesting short-term color stabilization. Analytical results demonstrated low coefficients of variation for most parameters after 20 days, indicating system consistency during storage. Sensory evaluation revealed that the formulation containing 6 g of extract exhibited a higher aromatic intensity and enhanced red fruit perception compared to the control wine. Overall, the results demonstrate that the incorporation of freeze-dried strawberry extract into a white wine matrix is technologically feasible and enables the controlled modulation of physicochemical and sensory properties without compromising short-term stability. Full article

Lignin is an abundant aromatic biopolymer, but its conversion into high-performance fibers remains challenging due to intrinsically poor spinnability, structural heterogeneity, and inefficient stress transfer in lignin-rich systems. In this study, a processing and structure strategy is demonstrated to overcome these limitations by transforming industrial black-liquor kraft lignin into a spinnable and load-bearing fiber component. Kraft lignin recovered from black-liquor waste was extracted and subsequently purified using a hot-water treatment to remove inorganic impurities and thermally unstable fractions, increasing lignin purity to 95.9% through extensive deionized water purification using a water-to-lignin ratio of 300:1. The purified lignin was then blended with poly(vinyl alcohol) (PVA), wet-spun into continuous filaments, and subjected to post-spinning hot drawing to induce molecular orientation. This sequential extraction, purification, blending, spinning, and drawing approach enables stable wet spinning and the continuous formation of lignin-rich lignin/PVA filaments without filament breakage, directly addressing the primary processing bottleneck of lignin-based fibers. Molecular-level miscibility between lignin and PVA is confirmed by the presence of a single glass transition temperature at 88.3 °C, indicating the formation of a homogeneous amorphous phase. SEM observations reveal composition-dependent surface roughness and non-circular cross-sectional morphologies arising from differential coagulation and shrinkage, demonstrating that lignin actively participates in the load-bearing fiber network rather than acting as a passive filler. As a result of purification-enabled spinnability, true blend miscibility, and post-spinning hot drawing, fibers with a lignin-to-PVA composition of 40:60 achieve a maximum tensile strength of 2.8 GPa, approaching the performance range of commercial high-strength polymer fibers. This work establishes a clear relationship between material structure, processing strategy, and resulting properties, highlighting the potential of industrial lignin waste as a sustainable precursor for advanced fiber applications. Full article

Using non-Saccharomyces yeasts is a promising way to modulate wine composition, particularly in warm regions where high sugar levels result in wines with high alcohol content and low acidity. This study examined the impact of various inoculation methods involving Lachancea thermotolerans and Metschnikowia pulcherrima on the chemical and aromatic profiles of Tempranillo wines. Five treatments were tested: a control with Saccharomyces cerevisiae; two sequential inoculations, with each non-Saccharomyces species followed by S. cerevisiae; and two co-inoculations of both species at different ratios, followed by S. cerevisiae. L. thermotolerans was found to significantly increase lactic acid levels, resulting in higher acidity and lower pH, particularly at higher doses. Wines inoculated with M. pulcherrima exhibited the highest levels of fruity esters, whereas L. thermotolerans increased higher alcohols, acetaldehyde and ethyl lactate, but reduced ester content. Co-inoculations produced intermediate or synergistic effects, depending on the proportions of the yeast species. Aromatic analysis indicated that treatments involving M. pulcherrima were associated with higher contributions to the fruity, floral and waxy aromatic series, while L. thermotolerans increases creamy series. Multivariate analysis clearly differentiated wines according to the dominant species. Overall, the co-inoculation of both yeasts is an effective method of modulating volatile composition and aroma-related parameters in warm-climate red wines. Full article

Chickpea flour represents a valuable plant-based ingredient due to its high protein and fiber content; however, its application is limited by antinutritional factors and off-flavor compounds. Fermentation with LAB and yeasts, applied individually or in consortia, resulted in significant microbiological, nutritional, and aromatic changes. The fastest acidification (pH 3.9) and the most effective control of Enterobacteriaceae (<4 log CFU/g after 48 h) were observed in samples containing Lactiplantibacillus plantarum LP23, both as a monoculture and in combination with Debaryomyces hansenii Y15A. Peptide content significantly increased in all fermented samples compared to the control, with a synergistic effect in the co-culture Yarrowia lipolytica Y3 + Lacticaseibacillus paracasei L (around 230%). A pronounced reduction in raffinose-family oligosaccharides was observed, especially in the consortia Y. lipolytica Y3 + Lcb. paracasei L and D. hansenii Y15A + Lacp. plantarum LP23 (0.11–0.16 mmol/100 g). Samples with lower total volatile levels showed higher olfactory acceptability due to a marked reduction in aldehydes (up to 70–95% vs. control), and a balanced accumulation of alcohols, esters, ketones, and organic acids. Overall, LAB–yeast consortia effectively enhanced the nutritional quality, safety, and sensory properties of chickpea flour, supporting its use as a functional ingredient in plant-based foods. Full article