Search Results (55)

Sustainability challenges in the wine sector have intensified the need for alternatives to conventional oak barrel maturation, a practice associated with high wood consumption, long maturation periods, and considerable economic and environmental cost. This study evaluates a resource-efficient maturation strategy for white wine using an experimental design comparing conventional oak alternatives with ultrasound-assisted extraction. Experiments were conducted in triplicate (n = 3) considering oak type (French chips vs. granules), dosage, toasting level (fresh, light, medium), and contact time (10 vs. 20 days). To enhance mass transfer, a 15 min ultrasound treatment (35 kHz) was applied. Statistical analysis (ANOVA One Way) indicated that oak fragment type and contact time significantly governed phenolic extraction (p < 0.05). Gallic acid concentrations increased significantly from 1.54 ± 0.03 mg L⁻¹ in the control to 4.41 ± 0.12 mg L⁻¹ in the most intensive ultrasound-assisted extraction treatment (p < 0.05). Syringaldehyde concentrations also showed a significant rise (1.13 to 1.44 mg L⁻¹; p < 0.05). Ultrasound significantly accelerated extraction kinetics while mitigating the loss of flavan-3-ols (≤28%) compared to conventional oak treatments (up to 34%). Economic assessment demonstrated a substantial reduction in production costs, from 0.21–0.56 € L⁻¹ range for standard fragment treatments to 0.05–0.07 € L⁻¹ when ultrasound was applied. Cost-efficiency metrics (<0.03 € mg⁻¹ gallic acid) confirmed that the combination of ultrasound and alternative oak materials provides an optimal, statistically significant balance between phenolic yield and economic viability. 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

Tool wear remains a critical limiting factor in machining performance, particularly in dry cutting conditions where friction and tribological interactions dominate. This study investigates the influence of a 5–8 μm PVD-deposited TiN coating on the wear behavior of high-speed steel (HSS) end mills during milling of three representative wood species (oak, beech, and fir). A spatially resolved wear evaluation methodology was employed, based on ten measurement points distributed along a 20 mm active cutting edge, enabling simultaneous assessment of mean wear and maximum localized wear (Umax). A factorial experimental design combining material type and feed rate (1500–2500 mm/min) was analyzed using two-way ANOVA with effect size quantification (η²). The results reveal a statistically significant reduction in mean wear for TiN-coated tools (F = 7.46, p = 0.0195, η² = 0.34), corresponding to an average decrease of approximately 46% compared to uncoated tools. Maximum wear was influenced by both coating (F = 14.73, p = 0.0028, η² = 0.399) and material (F = 4.37, p = 0.040, η² = 0.237). The experimental findings are interpreted through a tribological framework, indicating a transition from abrasion- and micro-chipping-dominated degradation in uncoated tools to a controlled wear regime in TiN-coated tools, characterized by reduced asperity penetration, delayed crack initiation, and limited tribochemical interactions. These results demonstrate that coating effects dominate global wear evolution, while material properties influence localized degradation. The proposed combined experimental–statistical–mechanistic approach provides a robust framework for understanding and optimizing tool performance in dry machining environments. Full article

Oak (Quercus spp.), traditionally used for aging alcoholic beverages, is not native in many countries, which increases production costs and environmental impact. During the aging process of alcoholic beverages, complex physical and chemical transformations occur that determine their chemical composition and sensory quality, many of which are unique depending on the type of wood used in the process. In this context, Maclura tinctoria (Tajuva), a native Brazilian species rich in phenolic compounds, was evaluated based on its phenolic composition and extraction behavior as a sustainable alternative for beverage aging. Wood chips were subjected to three toasting levels (untoasted, medium, and high) and aged for up to 360 days in two hydroethanolic model systems (10% and 14% v/v ethanol). The total and individual phenolic compounds were determined using the Folin–Ciocalteu method and HPLC–DAD/LC–MS/MS analysis. Results showed that toasting level, ethanol concentration, and aging time significantly influenced phenolic extraction. Untoasted Tajuva released the highest amounts of phenolic acids and flavonoids, particularly gallic and caffeic acids, and quercetin, respectively; while medium toasting favored the formation of thermally derived aromatic compounds, such as vanillic acid. The 14% ethanol system enhanced extraction efficiency for most analytes. Overall, Tajuva wood exhibited higher phenolic yields than French oak under comparable conditions, highlighting its chemical richness and extraction reactivity. These findings support the use of M. tinctoria as an eco-efficient and functional alternative to oak for the maturation of alcoholic beverages. Full article

Jerez vinegar is a high-quality wine vinegar produced in the Vinagre de Jerez denomination of origin (Spain) and is traditionally aged in wood barrels for over 10 years. Considering the long aging process, a practical technique to accelerate the aging process was simulated. This study aimed to evaluate ultrasound and microwave treatments as alternative aging methods for fresh Jerez vinegars with oak chips, and to investigate their effects on phenolic content, volatile compounds, and colorimetric and sensory properties. Fresh control samples with oak chips were treated using ultrasound (US) in an ultrasonic bath three times: 0.5 h (US1), 2 h (US2), and 10 h (US3). Microwave (MW) treatments were performed using a domestic microwave oven with three power/time combinations: 640 W for 10 min (MW1), 640 W for 20 min (MW2), and 800 W for 10 min (MW3). Compared with the fresh control (4230 µg/kg), US- and MW-treated samples showed a significant reduction in total phenolic content, decreasing to 3943 µg/kg in the US1 sample and to 3988 µg/kg in the MW2 treatment. Moreover, volatile substances significantly decreased from 1019 mg/L in the fresh control to 623 mg/L in the US3 treatment and 716 mg/L in the MW1 sample. Regarding sensory properties, US3 and MW1 treatments exhibited marked distinctions in certain odor and flavor attributes when compared with the fresh control. As a result, both techniques modified the phenolic, volatile and sensory profiles. Further research is needed to fully mimic the aging process, but US has proven to be a promising technique. Full article

Wines produced from grapes exposed to wildfire smoke exhibit smoke-related flavors, such as smoky, burnt, and an ashy finish. While grapes are impacted on the vine, winemaking strategies can influence the perception of smoke-related properties in the resulting wine. This case study evaluated eight smoke-affected wines across three vintages from commercial production to assess how oak influences smoke-related flavors. Each vintage explored a different usage of oak, including oak origin, oak chips with carbon fining, and potential carryover of flavors through reused barrels. Wines were assessed using descriptive analysis, with intensity ratings collected for seven attributes representing smoke-related and typical wine flavors. Results showed that American oak reduced the perception of smoke-related flavors compared to French oak. The use of oak chips, both alone and with carbon fining, did not improve the flavor profile. This suggests that combining treatments should be approached with caution, especially when strategies target smoke taint mitigation through different mechanisms. Sensory results also indicated no evidence of smoke flavor carryover from using barrels that previously held smoke-affected wine. Overall, this work showed that oak can influence sensory profile of smoke-affected wines and consideration of different wine production practices can be beneficial when faced with a smoke-impacted vintage. Full article

Emerging pollutants such as organophosphate flame retardants (OPFRs) pose a critical threat to environmental and human health, while conventional wastewater treatments often fail to remove them. This study addresses this issue by evaluating the bioremediation potential of white-rot fungi for the removal of two OPFRs: tris(2-chloroethyl) phosphate (TCEP) and tributyl phosphate (TBP). Three fungal species—Ganoderma lucidum, Trametes versicolor, and Phanerochaete velutina—were screened for their degradation capabilities. Among these, G. lucidum and T. versicolor demonstrated removal efficiencies exceeding 99% for TBP, while removal rates for TCEP were significantly lower, with a maximum of 30%. The exploration of the enzyme role showed that cytochrome P450 is involved in the degradation while the extracellular laccase is not involved. Continuous batch experiments were performed using a trickle-bed reactor (TBR) operating under non-sterile conditions, a setting that closely resembles real-world wastewater treatment environments. G. lucidum was immobilized on oak wood chips, and the removal efficiencies were measured to be 85.3% and 54.8% for TBP and TCEP, respectively, over 10 cycles. Microbial community analysis showed that G. lucidum remained the dominant species in the reactor. These findings demonstrate the efficacy of fungal-based trickle-bed bioreactors, offering a sustainable and efficient alternative for addressing environmental pollution caused by highly recalcitrant pollutants. Full article

The traditional practice of aging wines in oak barrels has long been associated with the evolution of wine aromas. However, due to rising costs, alternative approaches like aging with oak chips have gained popularity. The aging time, addition dose, and type of toasting of the oak chips are critical parameters affecting the quality of the wine’s aroma. In this study, we focus on wines from Agiorgitiko variety and explore the impact of oak chip maturation on both volatile composition and sensory profile. By analyzing volatile compounds of wine aroma using GC-MS/MS and conducting descriptive sensory analysis, we investigate the effects of three different oak chip toasting levels, three dosages, and three aging periods. Our findings reveal that almost all wines aged with oak chips exhibit higher ester concentrations compared to the control. Notably, heavily toasted oak chips contribute to the sensory attribute of smoky aroma, while medium oak chips are associated with the sensory attribute of barrel aroma. This study provides valuable data for winemakers to determine the most suitable application for their product. Full article

By analyzing the sugars extracted from oak chips toasted at various temperatures (180 to 280 °C) for various durations (10 to 30 min) in a model wine, we examined how wood polysaccharides are affected by toasting. The responses induced by toasting significantly differed among the major sugars constituting the wood. The main components of wood polysaccharides—glucose, arabinose, galactose, and xylose—were analyzed, and the results showed that galactose had the highest extraction amounts at around 220 °C of toasting, xylose at around 240 °C, and glucose at around 280 °C. On the other hand, the extraction amounts decreased with longer toasting durations. These results suggest that wood polysaccharides undergo temperature-dependent depolymerization while simultaneously undergoing denaturation. In addition, these depolymerization reactions tended to shift towards lower temperatures with longer toasting durations. The results of this study elucidate the chemical changes that occur within the wood during the toasting of oak chips and highlight the importance of the relationship between toasting temperature and duration. Additionally, this study demonstrated that by using the sugars extracted from oak chips as indicators, it is possible to partially visualize the reactions that occur within oak chips during toasting. Full article

Retsina, Greece’s most renowned traditional wine, has been produced for millennia, with archaeological and historical evidence supporting its legacy. It is legally defined as wine made exclusively in Greece using grape must infused with Aleppo pine resin (Pinus halepensis). This study examines the effects of varying resin concentrations (0.5 g/L and 1 g/L), two commercial yeast strains, and medium-toast oak (Nadalié Cooperage, Ludon-Médoc, France) American and French, on Retsina’s chemical and sensory properties to optimise its production. Wine samples from the Savatiano grape variety were analysed for classical wine parameters, oxidation stability, volatile compounds, organic acids, phenolic profiles, and sensory attributes. Principal Component Analysis (PCA) revealed that yeast strain selection significantly influences chemical composition, with Zymaflore X5 associated with higher organic acid levels. Oak addition altered phenolic profiles, with American oak increasing ellagic acid, while non-oaked wines showed higher syringic and p-coumaric acids. Resin addition elevated alpha-pinene, a key marker of resin aroma, but reduced esters linked to fruity and floral notes. These findings highlight the complex interactions between resin, yeast, and oak, offering insights for enhancing Retsina’s quality while preserving its traditional character. Full article

From a circular bio-economy perspective, biomass valorization requires the implementation of increasingly efficient extraction techniques to ensure the environmental and economic sustainability of biorefining processes. This research focuses on optimizing the specialized metabolite extraction of Turkey oak chips from Quercus cerris L. by applying a 3 levels Full Factorial Design (FFD). The goal is to obtain an extract with the highest antioxidant activity [evaluated by 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP) assays] and specialized metabolites content [measured as total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), and hydrolysable tannins content (THC)]. With this objective, three different variables were investigated and compared: temperature (20 °C, 50 °C, 80 °C), solvents EtOH/H₂O (0%, 20%, 40%), and time (3 h, 6 h, 24 h), resulting in 27 different extracts. Following the FFD analysis, the optimal extractive conditions were determined to be 80 °C, 40% EtOH/H₂O, and 19.8 h. Finally, the prediction ability of FFD was compared with that of artificial neural network (ANN) for DPPH scavenging activity, FRAP, and TPC data based on the coefficient of determination (R²), mean absolute error (MAE), and root mean square error (RMSE). The results indicated that ANN predictions were more precise than FFD ones; however, both methods were useful in optimizing the extraction process as they returned comparable optimized extraction parameters. Full article

The effect of oak chips on the phenolic composition, color characteristics, and antioxidant capacity of Bobal red wines caused by contact with oak chips at different stages of the winemaking process has been studied. Performance liquid chromatography–diode array detection (HPLC-DAD) was used to determine the detailed phenolic composition of wines and antioxidant activity, and chromatic characteristics were determined by spectrophotometric methods. Standard red winemaking process was applied to make the Bobal control wine. The rest of the wines were elaborated with oak chip contact at two dose levels (3 and 6 g/L) in different phases of the winemaking process: during alcoholic fermentation (AF), during malolactic fermentation (MLF), and in young wines. The phenolic composition, antioxidant activity, and chromatic characteristics of Bobal control wines were slightly but significantly modified by contact with the oak chips. Wines in contact with oak chips during malolactic fermentation showed a decrease in the concentration of resveratrol-monomer stilbenes, monomeric anthocyanins, and pyranoanthocyanins. In general, the concentration of total resveratrol is influenced by the dose level used, resulting in a 10% decrease when the dose level is 6 g/L compared to the 3 g/L dose. Full article

This study aims to obtain an alternative aging method using toasted white oak chips and ultrasound technology that yields a final product of similar quality to the one obtained by a traditional aging system in reduced time. Different conditions of ultrasound treatment and ethanol concentration during the maturation stage were studied. A sugar cane honey spirit was produced. The ultrasound treatments were applied to the distilled product to extract the color, aroma, and flavor compounds from the white oak chips used. Trials of spectrophotometry-evaluated color and e-sensing technology were applied to assess flavor and aroma. Very distinct color changes were obtained, indicating that ultrasound treatment facilitates the extraction of color compounds from the oak chips. The flavor profile obtained was similar to the one obtained for the unaged reference, indicating that the accelerated aging treatment may not influence flavor in a significant manner. The aroma profile achieved most descriptors found in the commercial rum aroma profile, indicating that the aging method studied influences the aroma profile. In general, the methods used allowed us to produce an aged spirit, offering a reduction in maturation time over the traditional system and a similar sensory profile for the final product. Full article

Wood chips contain numerous active compounds that can affect the wine’s characteristics. They are commonly used in red grape wines, whisky, cherry and brandy, but in fruit wines, production is not typically utilised. The aim of this study was to compare the impact of an oak barrel ageing with the effect of the addition of chips made from various types of wood (oak, maple, cherry, apple) and with various degrees of toasting to the apple wines on their antioxidant, oenological and sensory properties. The oenological parameters, the polyphenols content, antioxidant activity and content of volatile odour-active compounds were assessed. It was shown that ageing in the presence of wood chips had a less noticeable effect on the oenological and sensory parameters of the wine than barrel ageing. Moreover, wood chips used did not significantly affect the acidity, alcohol and extract content of apple wines. Wines aged in the presence of oak chips (particularly lightly toasted) exhibited the greatest increase in polyphenols, while the polyphenol content of wines aged in the presence of other chips was not dependent on their toasting degree. The ageing of fruit wines with wood chips influences the volatile profile and the olfactory sensations, which can improve their quality. Full article

Tree branches from forest tree harvesting for the timber industry are an important energy feedstock. Solid biofuel in the form of wood chips, produced from branches, is an excellent renewable energy source for generating heat and electricity. However, the properties of wood chips as a solid biofuel produced from forest tree branches can vary greatly depending on the species from which they have been produced. Therefore, this study aimed to assess the thermophysical properties and elemental composition of fresh branches harvested from nine tree species (pedunculate oak, silver birch, European ash, common aspen, grey alder, Norway maple, Scots pine, European larch and Norway spruce) over three consecutive years (2020–2022). The branches of the tree species most commonly found in Polish forests (Scots pine) were characterized by the highest heating value (an average of 20.74 GJ Mg⁻¹ DM), the highest carbon content (an average of 55.03% DM), the lowest ash (an average of 0.60% DM) and nitrogen contents (an average of 0.32% DM), and low sulfur (an average of 0.017% DM) and chlorine contents (an average of 0.014% DM). A cluster analysis showed that the branches of all three coniferous tree species (Scots pine, Norway spruce and European larch) formed one common cluster, indicating similar properties. The branches of the European ash were characterized by the lowest wood moisture content (an average of 37.19% DM) and thus the highest lower heating value (an average of 10.50 GJ Mg⁻¹). During the three years of the study, the chlorine and ash contents of the branches of the tree species under study exhibited the highest variability. Full article