Search Results (204)

Acorns (Quercus spp.) are an underutilized forest resource with recognized nutritional and bioactive potential, making them promising candidates for the development of sustainable plant-based functional foods. This study aimed to valorize acorns through the formulation of two novel acorn-based products, a plant-based beverage, and a pudding, and to assess their nutritional properties, sensory acceptability, and, for the beverage, refrigerated shelf-life stability. The beverage was optimized as a neutral-flavored milk alternative, using sodium alginate as a natural clean-label stabilizer to enhance emulsion stability and physicochemical properties. The final formulation exhibited low energy density and a lipid profile rich in monounsaturated fatty acids, contributing to its nutritional and functional value. Throughout 63 days of storage at 4 °C, sodium alginate effectively prevented phase separation and supported the retention of antioxidant capacity, as evidenced by stable ferric reducing antioxidant power (FRAP) and total phenolic content, although ABTS radical scavenging activity declined over time. No microbial growth was detected during storage, confirming the adequacy of the applied thermal treatment and aseptic filling procedures applied. The acorn-based pudding, developed by adapting a traditional egg-based recipe, functioned as a proof of concept illustrating the technological versatility of acorns across distinct plant-based matrices, exhibiting a nutritional profile comparable to commercial counterparts and high consumer acceptability. Overall, this work demonstrates the technological feasibility and versatility of incorporating acorns into plant-based food matrices, supporting their potential as sustainable ingredients for the development of innovative value-added foods and contributing to the valorization of forest resources. Full article

Acorn flours from the six Mediterranean Quercus species (Quercus cerris, Quercus petraea, Quercus robur, Quercus ilex, Quercus pubescens, and Quercus rotundifolia) were systematically fractionated for polyphenols using ultrasonic-assisted extraction with seven solvent systems varying in polarity and composition (water at 20 and 40 min; acetone, ethanol, and methanol at 20% and/or 70% v/v). The total polyphenol content (TPC), non-tannic phenolic content (NTPC), tannin content (TC), antioxidant potential (DPPH, ABTS, and FRAP), and individual phenolic profiles through high-performance liquid chromatography (HPLC) were determined. The results showed that the botanical species primarily determined the TPC and TC, while the solvent composition significantly influenced the NTPC yield. Q. cerris yielded the highest average TPC (105.1 ± 3.8 mg GAE/g) and TC, supported by a gallotannin-dominated profile. Conversely, Q. rotundifolia exhibited the lowest values but the highest NTPC/TPC ratio (32.0%). Q. ilex featured species-exclusive ellagitannins, while Q. pubescens showed the highest specific antioxidant activity. For the targeted recovery, 20% acetone is recommended for tannins and 70% ethanol for the non-tannic fractions. These findings establish a species-resolved framework for valorizing acorn flours as functional ingredients, identifying high-tannin species requiring detannification and “sweet” varieties suitable for direct food application. Full article

Silver nanoparticles (AgNPs) were synthesized via a green approach using aqueous extract of Quercus robur acorn as a reducing and stabilizing agent. The synthesis process was optimized at 1 mM Ag⁺ concentration, yielding stable nanoparticles with a characteristic surface plasmon resonance peak at 445 nm. Structural and morphological analyses confirmed the formation of predominantly spherical nanoparticles with particle sizes ranging between 40 and 68 nm and a face-centered cubic crystalline structure. Phytochemical analyses revealed significantly higher total phenolic and total flavonoid contents in the crude acorn extract compared to the synthesized nanoparticles, indicating the involvement of these compounds in the phytoreduction process. Although antioxidant activity decreased after nanoparticle formation, phyto-mediated AgNPs (PAgNPs) exhibited notable antibacterial activity, particularly against Staphylococcus aureus with a minimum inhibitory concentration of 26 µg/mL. Antibiotic combination assays demonstrated additive and synergistic interactions depending on the tested microorganism. Gas Chromatography–Mass Spectrometry (GC–MS) analysis of acorn essential oil identified β-caryophyllene (43.1%) as the major component, suggesting the presence of bioactive terpenoids potentially contributing to nanoparticle stabilization. These findings demonstrate that Quercus robur acorn extract can serve as suitable phytogenic source for the controlled synthesis of silver nanoparticles with moderate antibacterial potential. Full article

Acorns (Quercus spp.) have a long history of use in human nutrition and represent an underutilized plant resource with considerable potential for sustainable food systems. In recent years, acorn flour (AF) has attracted scientific interest as an innovative ingredient, particularly in breadmaking, due to its lack of gluten, favorable nutritional profile, and technological functionality. This review summarizes bread made with AF as a sustainable and innovative food product, with particular emphasis on its technological properties, including rheological behavior, sensory attributes, and nutritional profile. To our knowledge, this review is among the first to integrate an analysis of recent technological advancements in breadmaking with the current European Union regulatory framework, specifically EU Organic Regulation 2018/848. By bridging the gap between food technology and legislative requirements, the review outlines a comprehensive pathway for the commercialization of acorns as a certified organic resource. It concludes that although acorns have significant potential to enhance food security and sustainability, further standardization and increased consumer awareness are necessary to ensure their successful market integration. Full article

This study aimed to optimize the formulation of gluten-free bread (GFB) based on rice flour (RF) and Quercus rotundifolia acorn flour (AF) by evaluating the combined effects of flour substitution (0%, 50%, and 100%) and water addition (90%, 100%, and 110%) on technological, textural, colorimetric, structural, and sensory properties. A three-level full factorial design (3²) combined with response surface methodology (RSM) was used to model and optimize product quality. The developed models showed high predictive performance (R² = 0.714–0.999; non-significant lack of fit), confirming their suitability for describing complex interactions in gluten-free systems. Water addition was the dominant factor influencing moisture, crumb structure, and textural softness, while AF mainly affected color, structure, and sensory attributes. Increasing acorn content significantly decreased lightness (L*) and increased redness (a*) and darkness index (DI), reflecting higher phenolic compound content and more intense Maillard reactions. Specific volume (1.85–2.41 cm³/g) was maximized at higher hydration levels, especially when combined with intermediate to high acorn substitution, indicating a synergistic interaction between fiber-rich flour and water availability. Texture analysis showed that AF increased hardness and reduced cohesiveness, while water addition significantly improved softness, elasticity, and overall mouthfeel. Image analysis of crumb structure demonstrated that higher hydration promoted larger pore size and porosity, whereas AF increased cell density, resulting in a finer crumb structure under low hydration conditions. Sensory evaluation confirmed that breads with high acorn content were well accepted due to their characteristic nutty flavor. Multi-response desirability optimization yielded an optimal formulation with approximately 83% AF and 108% water, representing the best achievable compromise among the evaluated quality criteria. The results demonstrate that AF can serve as a key functional ingredient in GFB, provided that hydration is carefully adjusted. This study highlights the effectiveness of RSM combined with image-based analysis as a robust approach for developing high-quality gluten-free bakery products. Full article

Quercus acorns have been part of animal or human diets; however, their nutritional potential depends on morphological and chemical characteristics highly influenced by genetic and geographical factors. Research on the Quercus genus has focused on Asian and European species overlooking the American taxa. Therefore, this study aimed to evaluate the morphological and nutritional characteristics, and the content and profile of bioactive compounds of acorns from four populations of the American species Quercus virginiana from the state of Chihuahua, Mexico. Discriminant function analysis showed a well-established group formed by the two southern populations (CH), while the two northern populations were separated into different groups (CJA and CJB). CH populations showed smaller seeds (1.4 g, 2.0 cm length) and higher starch (57–58%), oleic acid (65–70%), phenolic compounds (78–176 mg GAE/g), flavonoids (29–37 mg CE/g), and antioxidant activity (278–282 μmol TE/g). Acorns from the CJA population were the largest (2.3 g, 2.4 cm length) and displayed the highest protein content (7.0%). Acorns from the CJB population showed the highest values for ash (2.2%), sugars (13.8%), palmitic and linoleic acids (19.1%), and condensed tannins (0.26 CE/g). Fourteen polyphenolic compounds were identified: twelve hydrolysable tannins; one hydroxycinnamic acid, and one flavonol. These variations reflected the impact of local climatic and geographic conditions and may influence the potential use of Quercus acorns in sustainable agriculture and food development. Full article

Background/Objectives: Wound repair-associated processes and the antioxidant properties of natural products play critical roles in skin wound healing and barrier restoration. Wound healing is a complex process characterized by a series of interconnected events that facilitate the self-repair of the skin following injury. Methods: This study aimed to evaluate the effects of Quercus acuta acorn bran extract (QAABE) on wound healing using human dermal fibroblast (HDF) cell cultures treated with QAABE. Additionally, in vivo experiments were conducted using a mouse model of skin injury to assess the wound-healing potential of the extract. Results: The results indicated that QAABE enhanced wound healing in vitro by upregulating extracellular matrix-related markers, including vimentin, Col1a1, Col3a1, endothelin, fibronectin, and VEGF at the mRNA level, and increasing the protein expression of vimentin, COL1A1, endothelin, and α-SMA. QAABE also exhibited reactive oxygen species (ROS)-scavenging activity. In the mouse skin injury model, QAABE treatment accelerated wound closure and was associated with reduced inflammatory responses. Conclusions: These findings suggest that QAABE may promote wound-healing-related responses in both in vitro and in vivo models, supporting its potential as a candidate for further investigation in wound-healing research. Full article

Despite the growing demand for functional gluten-free (GF) foods, the application of Quercus pubescens acorn flour remains largely underexplored. This study addresses this gap by optimizing GF cookies using response surface methodology (RSM) and prepared with Q. pubescens acorn flour and xanthan gum to balance technological quality, sensory acceptability, and functional value. A three-level full factorial design (FFD) evaluated the effects of acorn flour proportion (0, 50 and 100%), and xanthan gum level (1, 2 and 3%) on physicochemical properties (moisture, water activity, color, texture, and dimensions), sensory attributes using a 9-point hedonic scale, proximate composition, and bioactive and antioxidant properties (total polyphenols, tannins, DPPH, ABTS, FRAP). Linear and quadratic polynomial models adequately described the experimental data (R² = 0.86–0.99; non-significant lack of fit). Increasing acorn flour content significantly intensified cookie darkening, reduced snapping force and bending stiffness, reduced spread factor, and affected sensory perception, while xanthan gum improved structural integrity and dimensional stability. Multi-response optimization identified an optimal formulation containing 41.05% acorn flour and 1.46% xanthan gum, achieving balanced color development (darkness index ≈ 62), bending stiffness (~38 N/mm), and high overall sensory acceptability (~7.8). The optimized GF cookies exhibited a favorable nutritional profile and antioxidant properties, characterized by elevated total polyphenol content and antioxidant capacity, confirming the functional potential of acorn flour. The optimized cookies (containing 41.05% acorn flour) exhibited a six-fold increase in total phenolic content (from 1.63 to 10.08 mg GAE/g) and 8–10 times higher antioxidant capacity (DPPH, ABTS, and FRAP assays) compared to the control, confirming the substantial functional potential of Q. pubescens in gluten-free systems. Full article

Acorns represent an underutilized source of forest biomass with potential for producing edible oils and bioactive compounds. This research compared lipid fractions from pedunculate oak (Quercus robur L.) and northern red oak (Quercus rubra L.) collected in Poland, examining how different extraction methods influence oil yield and quality. Oils were extracted using Soxhlet with hexane, cold hexane extraction for both species, and mechanical pressing for Q. rubra. Fatty acid profiles analyzed by GC-FID facilitated calculation of lipid quality indices. Oxidative stability was assessed through isothermal PDSC, and total phenolics, flavonoids, and antioxidant activity (DPPH, ABTS) were measured in acorn extracts. Q. rubra produced more oil than Q. robur regardless of extraction method, but Q. robur oils exhibited significantly higher PDSC oxidation times (τ_on, τ_max). Pressed Q. rubra oil showed higher acid and peroxide values compared to solvent-extracted oils. Fatty acid composition was predominantly influenced by species rather than by extraction method, as confirmed by multivariate analysis, which indicated species as the main driver of variability. Overall, these results highlight a trade-off between oil yield and oxidative stability, suggesting acorns as a promising, species-dependent oil resource. Full article

This study aims to evaluate the interspecific variation in polyphenolic profiles and biological activities of acorn flours from three native Tunisian Quercus L. species (Q. ilex L., Q. suber L., and Q. canariensis Willd.). Q. canariensis extracts are the richest in total phenolic, flavonoid and hydrolysable tannin contents. Six phenolic compounds were identified by HPLC-DAD analysis. Chlorogenic acid was the dominant compound in Q. canariensis and Q. ilex acorns. Whereas in Q. suber, caffeic acid was the main component and, along with trans-ferulic acid, was exclusive to this species. Hyperoside was notably identified in Q. canariensis. The UHPLC-DAD-MS analysis of hydrolysable tannins revealed twelve compounds. Acorns of Q. canariensis and Q. suber were dominated by ellagitannins, whereas Q. ilex contained mainly gallotannins. To our knowledge, these compounds are identified for the first time in Tunisian acorns. Q. canariensis exhibited the strongest antioxidant potential with DPPH, ABTS and FRAP assays, as well as the highest antibiofilm and anti-α-amylase activities. All extracts inhibited ATCC pathogenic bacterial strains while largely sparing the beneficial probiotic Limosilactobacillus fermentum. This result indicates a selective antibacterial effect not previously reported for Quercus acorns. Q. canariensis may represent a potential source of functional food ingredient, nutraceuticals, and pharmaceuticals, which remains to be confirmed through in vivo investigations. Full article

Acorns of the Quercus species are rich in tannins, but their phytochemistry remains insufficiently characterized. This study provides characterization of the antioxidative and antimicrobial activities of twelve phenolic compounds, including gallic acid and catechin, extracted with ethanol and hot-water from evergreen oak Quercus acuta. Samples collected from mature trees were pooled to minimize variation. Extracts were prepared from leaves, branches, pericarps, and kernels. Antioxidant capacity was evaluated using DPPH and ABTS⁺ assays, while antimicrobial activity was assessed against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Kernel ethanol extracts showed the highest antioxidant activity, exhibiting 76% DPPH and 59% ABTS⁺ scavenging at 25 µg/mL, and demonstrated selective inhibition against P. aeruginosa. Ethanol extracts contained higher levels of polyphenols, flavonoids, and tannins than hot-water extracts; kernels showed the highest flavonoid and tannin contents, whereas leaves were rich in catechin. HPLC–MS/MS analysis identified twelve phenolic compounds, with gallic acid being most abundant in kernel ethanol extracts. Principal component and correlation analysis revealed distinct distribution patterns of phenolic compounds among plant parts and a strong positive association between gallic acid content and both antioxidative and antimicrobial activities. Overall, Q. acuta kernels represent a rich source of bioactive phenolics with potential antioxidative and antimicrobial applications. Full article

Heavy metals are major toxic anthropogenic contaminants released into the environment mainly through wastewater discharges. Adsorption is one of the most effective and widely applied methods for their removal from aqueous systems. However, although activated carbon is commonly used, its high cost and limited regenerability motivate the search for cheaper and more environmentally friendly alternatives. In this study, selected natural and waste-derived materials were evaluated for Cu²⁺ removal from both model solutions and atypical textile wastewater. Coffee grounds, chestnut seeds, acorns, potato peels, eggshells, marine shells, and poultry bones were tested and compared with commercial activated carbon. Their structural and functional properties were characterised using specific surface area measurements, optical microscopy, SEM-EDS, and FTIR analyses. Two adsorption isotherm models (Langmuir and Freundlich) were used to analyse the experimental data for the selected adsorbents, and model parameters were determined by linear regression. Based on model solution tests, two materials showed the highest Cu²⁺ sorption potential: coarse poultry bones (97.0% at 24 h) and fine cockle shells (96.2% at 24 h). When applied to real textile wastewater, the bone-derived material achieved the highest Cu²⁺ removal efficiency (79.4%). Although this efficiency is lower than typical values obtained in laboratory solutions, it demonstrates the feasibility of waste-derived materials as low-cost adsorbents and suggests that further optimisation could further improve their performance. Full article

An environmentally friendly extraction strategy based on an MSAT (Medium Scale Ambient Temperature) system was applied to Quercus ilex and Quercus robur acorns with the aim of maximizing polyphenolic yield and antioxidant activity while minimizing solvent consumption. Operational parameters were first optimized for Quercus ilex using a BBD-RSM (Box–Behnken response surface methodology), where the optimum working zone corresponds to the values of 200 g of acorn, 100 mL of extracting solvent, and 0.5 dispersant/acorn ratio. Subsequently, these conditions were applied to Quercus robur to enable an interspecific comparison. Extracts were evaluated in terms of total polyphenolic content, antioxidant activity, reducing sugars, proteins, targeted polyphenols quantified by UHPLC-QToF, and antimicrobial activity. Optimal extractions from Quercus ilex reached 25,072 mgGAE L⁻¹ and 162 mmolTE L⁻¹, while Quercus robur extracts showed markedly superior values of 35,822 mgGAE L⁻¹ and 234 mmolTE L⁻¹. Polyphenol quantification revealed higher concentrations of gallotannins in Quercus robur and procyanidins and catechin in Quercus ilex. The extracts showed strong antibacterial activity, especially Quercus ilex against S. aureus with a MIC ≤ 0.63%. Furthermore, it has been demonstrated for the first time that acorn extracts can inhibit the growth of Phytophthora cinnamomi in vitro, with Quercus robur extracts having a MIC ≤ 0.1% and Quercus ilex extracts ≤ 1%. Full article

The growing demand for biodegradable and functional packaging has driven research toward polysaccharide-based materials with improved performance. In this study, sodium alginate films were modified using natural deep eutectic solvents (NADES) and acorn polyphenolic extract to enhance their antimicrobial, mechanical, and thermal properties. The films were acquired by solvent casting and characterized through mechanical, spectroscopic, thermal, and microbiological analyses. Both NADES and the polyphenolic extract enhanced tensile strength and flexibility through additional hydrogen bonding within the alginate network, while the extract also introduced antioxidant functionality. Among all tested formulations, the A4E2 film exhibited the most balanced performance. FTIR spectra revealed hydrogen bonding between the film components, and thermogravimetric analysis showed an approximately 15 °C (F-EXT) and 20 °C (F-DES) shift in the main DTG degradation peak, indicating enhanced thermal stability. Controlled-release experiments demonstrated the gradual diffusion of phenolic compounds in aqueous, acidic, and fatty simulants, with an initial release phase within the first 6 h followed by sustained release up to 48 h, confirming the films’ suitability for various food environments. The combined modification reduced the growth of Escherichia coli and Staphylococcus aureus by 30–35%, with inhibition zone diameters reaching 27.52 ± 2.87 mm and 25.68 ± 1.52 mm, respectively, evidencing synergistic antimicrobial activity. These results highlight the potential of NADES- and extract-modified alginate films as sustainable materials for active food packaging applications. Full article

Despite their substantial contributions to herd productivity, culled sows typically receive minimal economic valorisation. This study evaluated the feasibility of finishing culled Iberian sows under free-range conditions (montanera finishing system) and assessed the effects of immunocastration on productivity, welfare, and meat quality. Thirty-six culled Iberian sows were assigned to two treatments: entire sows (n = 18) and immunocastrated sows (n = 18). Following a maintenance phase and a pre-finishing transition, animals were finished under montanera conditions with ad libitum access to acorns and pasture. Productive traits, welfare indicators, carcass traits, and meat quality parameters were evaluated. Immunocastration effectively suppressed reproductive function without compromising productive traits or meat quality in culled Iberian sows. Both groups exhibited comparable body weight evolution, carcass characteristics, and meat quality attributes consistent with Iberian standards. The results indicate a clear potential for value generation, transforming animals from minimal-value culling categories to premium montanera products. This integrated approach combining immunocastration with traditional extensive finishing systems provides a viable way to add value to culled sow valorisation within circular economy frameworks, addressing economic, environmental, and welfare challenges of sustainable livestock production. Full article