The effect of aqueous extract of Iranian oak (Quercus brantii) on antioxidant capacity and oxidative stress in beta-thalassemia patients: Randomized controlled trial.

BACKGROUND AND AIM: Frequent administration of blood in ß-thalassemia patients can lead to over-loaded iron, a reduction in the levels of antioxidant activities in the body, and oxidative stress. This study was done to evaluate the antioxidant and protective effect of aqueous oak (Quercus brantii) extract supplementation on these patients. METHODS: This clinical trial was performed on 60 major ß thalassemia patients dividing them into intervention and control groups. In addition to taking desferrioxamine (DFO), the control and intervention groups received respectively placebo capsule supplementation and aqueous Quercus extract capsules (300 mg/day) for 3 months. Serum lipid profiles (LDL-c, HDL-c, triglyceride), Total Antioxidant Capacity (TAC), Glucose, Uric acid, urea nitrogen (BUN), Creatinine, LFT (Liver Function Tests) such as SGOT, SGPT, ALP, Total bilirubin, Direct bilirubin, ferritin, MDA and carbonyl protein (CO) levels were measured before and after the period. In addition, the activity of catalase (CAT), and superoxide dismutase (SOD) was measured in the red blood cell. Furthermore, antioxidant activity and total phenolic content of aqueous Quercus were recorded to standardize capsule formulation. RESULTS: Mean serum MDA, and protein CO, significantly decreased in the intervention group with ß-TM after 3 months of treatment with Quercus extract. In addition, the superoxide dismutase (SOD) enzyme and Total antioxidant capacity (TAC) significantly increased in comparison with the control group. Changes in serum creatinine, BUN, and alanine transferase were not significant. In the study, Quercus extract capsules contain 48/56 mg gallic acid/g (dry extract) total phenol, 58/6 mg/g (dry extract), and flavonoids of 63/8 µg/ml antioxidant power which by GC/MS analysis has been measured. At the end of the study, serum MDA decreased from 48.65 ± 8.74 to 43.94 ± 10.39 µ mol/l after administration of oak extract and protein CO dropped from 2.44 ± 0.38 to 1.2 ± 0.31 nmol DNPH/mg protein after administration of the oak extract. At the end of the study serum, TAC increased in patients interventional group from 907 ± 319 to 977 ± 327 µmol FeSO4/l compared to the control group 916 ± 275 to 905.233 ± 233 µmol FeSO4/l with placebo, and SOD increased from 1577 ± 325 to 2079 ± 554 U/l (compared to 1687 ± 323 U/l with placebo). The treatment effect of Quercus was measured using a mixed-effects model of variance analysis for changes in MDA, protein CO, TAC, and SOD, with significant effects being demonstrated for each laboratory parameter (P = 0.15, P = 0.001, P = 0.02, and P < 0.003, respectively). CONCLUSIONS: Aqueous Quercus extract, due to its high antioxidant potential, reduced MDA, serum carbonyl protein, and increased superoxide dismutase activity effectively decreased serum OS and enhanced serum antioxidant capacity in patients with ß-thalassemia major. oak given as an adjuvant therapy to standard iron chelators may provide an improvement in the OS measurements obtained in these patients. REGISTRATION INFORMATION: This study was submitted, evaluated, and approved by the Iranian Registry of Clinical Trials (IRCT: http://www.irct.ir; IRCT2015101411819N4), which was established for national medical schools in Iran.

Deep eutectic solvent pretreatment of cork dust - Effects on biomass composition, phenolic extraction and anaerobic degradability.

In this study, phenolic compounds using deep eutectic solvents (DES) were extracted from cork dust, and the biogas production potential of DES-treated cork dust samples was determined. The DES treatment was carried out using choline chloride and formic acid (1:2 M ratio) at various temperatures (90, 110 and 130 °C) and treatment times (20, 40 and 60 min) at a solid-to-solvent ratio of 1:10 g mL-1. The highest total phenolic content (137 mg gallic acid equivalent (GAE) g-1 dry cork dust) was achieved at 110 °C/20 min. The extracts exhibited an antioxidant capacity of up to 56.3 ± 3.1 % 1,1-diphenyl-2-picrylhydazyl (DPPH) inhibition at a dilution rate of 100. DES treatment resulted in minimal sugar solubilization at low temperatures, while approximately 42 % of the xylan fraction in the biomass degraded under severe conditions (e.g., 130 °C/60 min). Catechin, 4-hydroxybenzoic acid and gallic acid were the major phenolics in DES extracts. The biogas yield of DES-treated cork dust increased with treatment severity. The highest biogas yield (115.1mLN gVS-1) was observed at 130 °C/60 min, representing an increase of 125 % compared to the untreated sample. SEM images revealed that the surface structure of the samples became smoother after mild pretreatment and rougher after harsh pretreatment. Compositional and FTIR analyses indicated that a higher biogas formation potential was associated with increased cellulose content in the substrate, which could be attributed to hemicellulose solubilization in the hydrolysate. Overall, DES pretreatment effectively enhanced phenol extraction and anaerobic degradability.

Detecting Pathogenic Phytophthora Species Using Volatile Organic Compounds.

There are several highly damaging Phytophthora species pathogenic to forest trees, many of which have been spread beyond their native range by the international trade of live plants and infested materials. Such introductions can be reduced through the development of better tools capable of the early, rapid, and high-throughput detection of contaminated plants. This study utilized a volatilomics approach (solid-phase microextraction coupled to gas chromatography-mass spectrometry) to differentiate between several Phytophthora species in culture and discriminate between healthy and Phytophthora-inoculated European beech and pedunculate oak trees. We tentatively identified 14 compounds that could differentiate eight Phytophthora species from each other in vitro. All of the Phytophthora species examined, except Phytophthora cambivora, uniquely produced at least one compound not observed in the other species; however, most detected compounds were shared between multiple species. Phytophthora polonica had the most unique compounds and was the least similar of all the species examined. The inoculated seedlings had qualitatively different volatile profiles and could be distinguished from the healthy controls by the presence of isokaurene, anisole, and a mix of three unknown compounds. This study supports the notion that volatiles are suitable for screening plant material, detecting tree pathogens, and differentiating between healthy and diseased material.

Temporal dynamics of lignin degradation in Quercus acutissima sawdust during Ganoderma lucidum cultivation.

Despite a fair amount of lignin conversion during mycelial growth, previous structural analyses have not yet revealed how lignin changes continuously and what the relationship is between lignin and ligninolytic enzymes. To clarify these aspects, Quercus acutissima sawdust attaching Ganoderma lucidum mycelium collected from different growth stage was subjected to analysis of lignin structure and ligninolytic enzyme activity. Two key periods of lignin degradation are found during the cultivation of G. lucidum: hypha rapid growth period and primordium formation period. In the first stage, laccase activity is associated with the opening of structures such as methoxyls, ß-O-4' substructures and guaiacyl units in lignin, as well as the shortening of lignin chains. Manganese peroxidases and lignin peroxidases are more suitable for degrading short chain lignin. The structure of phenylcoumarans and syringyl changes greatly in the second stage. The results from sawdust attaching mycelium provide new insights to help improve the cultivation substrate formulation of G. lucidum and understand biomass valorization better.

Effectiveness of cork and pine bark powders as biosorbents for potentially toxic elements present in aqueous solution.

Cork oak and pine bark, two of the most prolific byproducts of the European forestry sector, were assessed as biosorbents for eliminating potentially toxic elements (PTEs) from water-based solutions. Our research suggests that bioadsorption stands out as a viable and environmental eco-friendly technology, presenting a sustainable method for the extraction of PTEs from polluted water sources. This study aimed to evaluate and compare the efficiency of cork powder and pine bark powder as biosorbents. Specifically, the adsorption of Fe, Cu, Zn, Cd, Ni, Pb and Sn at equilibrium were studied through batch experiments by varying PTEs concentrations, pH, and ionic strength. Results from adsorption-desorption experiments demonstrate the remarkable capacity of both materials to retain the studied PTE. Cork powder and pine bark powder exhibited the maximum retention capacity for Fe and Cd, while they performed poorly for Pb and Sn, respectively. Nevertheless, pine bark showed a slightly lower retention capacity than cork. Increasing the pH resulted in cork showing the highest adsorption for Zn and the lowest for Sn, while for pine bark, Cd was the most adsorbed, and Sn was the least adsorbed, respectively. The highest adsorption of both materials occurred at pH 3.5-5, depending on the PTE tested. The ionic strength also influenced the adsorption of the various PTEs for both materials, with decreased adsorption as ionic strength increased. The findings suggest that both materials could be effective for capturing and eliminating the examined PTEs, albeit with different efficiencies. Remarkably, pine bark demonstrated superior adsorption capabilities, which were observed to vary based on the specific element and the experimental conditions. These findings contribute to elucidating the bio-adsorption potential of these natural materials, specifically their suitability in mitigating PTEs pollution, and favoring the recycling and revalorization of byproducts that might otherwise be considered residue.

Chemical characterization and sensory properties of apple brandies aged with different toasted oak chips and ultra-high-pressure treatments.

Aging is an important processing step of producing high quality apple brandy. In this study, apple brandies aged by traditional method and using three different toasted oak chips combined with or without ultra-high-pressure (UHP) treatment were prepared to compare their differences in chemical characterization and sensory properties. The results indicated that the brandies aged with toasted oak chip increased the levels of total acidity, volatile acidity and phenolic compounds. It also had the desirable color and taste. The brandy aged with toasted oak chip combined with UHP reached the highest levels of total acidity (1.06 g/L), total phenolic content (284.92 mg/L) and aromatic esters (49.37 %). Therefore, the aging with high toasted oak chip combined with UHP treatment could cut the traditional aging time to meet the same quality as traditional aging method. The results are very useful to develop a fast and efficient aging technique for brandy production.

Suberin, the hallmark constituent of bark, identified in a 45-million-year-old monkeyhair tree (Coumoxylon hartigii) from Geiseltal, Germany.

Suberin, a complex biopolymer, forms a water- and gas-insoluble barrier that protects the inner tissues of plants. It is abundant in tree bark, particularly in the cork oak Quercus suber. Anatomically, fossil bark has been described since the Devonian. However, its distinctive constituent suberin has not yet been reported from the fossil record. Here we present unambiguous chemical evidence for intact suberin from the bark of a middle Eocene monkeyhair tree from Geiseltal, eastern Germany. High-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) detected constituents of suberin in the outer layer the fossil monkeyhair tree, which confirms previous morphological interpretation of this tissue as bark, and chemically differentiates this layer from the two tissues of the inner layer. Notably, this is the first study with compelling chemical evidence for suberin in fossil bark. Fluorescence microspectroscopy additionally supports the presence of suberin. Fossilization conditions in the Eocene Geiseltal deposit were likely mild, with low moisture and temperatures, contributing to the remarkable preservation of bark and inner laticifer mats of the monkeyhair trees growing there 45 million years ago.

Structure and properties of Quercus robur acorn starch extracted by pulsed electric field technology.

Pulsed electric field (PEF) technology was used to extract starch from Q. robur flours using low-intensity electric fields (0 and 0.1 kV/cm) and study the impact of PEF on the structure and properties of acorn starch concerning commercial starch. PEF technology is an advantageous method for starch extraction than the aqueous steeping from an industrial perspective since reduces extraction time and allows for continuous processing of larger suspension volumes. PEF technology preserved the amylose and amylopectin contents, hydrogen bonds, and diffraction patterns, as well as the starch native properties. Hence, PEF could be used to obtain native starches, but future studies should verify its economic viability. Acorn starches have lower damaged starch content, gelatinization temperatures, enthalpies, improved pseudoplastic behavior, reduced in-vitro digestibility, and lower resistance to deformation compared to commercial corn starch. The higher solubility and swelling power of acorn starches up to 80 °C make them a suitable food additive in fermented yogurt and milk products and thus help to value acorn and acorn starches. Hence, acorns can be used to obtain native starches, a food ingredient with a wide range of food and non-food usage, using PEF.

Influence of Oak Species, Toasting Degree, and Aging Time on the Differentiation of Brandies Using a Chemometrics Approach Based on Phenolic Compound UHPLC Fingerprints.

Oak wood is the main material used by coopers to manufacture casks for the aging of spirits or wines. Phenolic compounds are the main components extracted from the wood during spirit aging. In the present study, a chemometric approach based on unsupervised (PCA) and supervised (PLS-DA) pattern recognition techniques has been applied to the chromatographic instrumental fingerprints, obtained by ultra-high-performance liquid chromatography (UHPLC) at 280 nm, of the phenolic profiles of brandies aged in casks made of different oak wood species. The resulting natural data groupings and the PLS-DA models have revealed that the oak wood species, the toasting level, and the aging time are the most influential factors on the phenolic profile of the final products. Fingerprinting should be considered as a very useful feature, as it represents a considerable advantage, in terms of internal and quality control, for brandy producers.

Effectiveness of plant-based hand sanitizer incorporating Quercus infectoria gall extract.

AIMS: Quercus infectoria (Qi), a traditional herbal plant with a broad spectrum of activities on multidrug-resistant bacteria, has been developed for hand sanitizer applications. METHODS AND RESULTS: Antimicrobial activity was evaluated using agar-well diffusion and broth microdilution method. Bactericidal activity was determined following the European Standard 1276 antibacterial suspension test. Neutralization assay was performed to assess antirespiratory syncytial virus. Safety, stability, and skin permeation of Qi hand gel was investigated. Qi hand sanitizer gel inhibited microorganisms ranging from 99.9% to 99.999% against Enterococcus faecalis, Staphylococcus aureus, methicillin-resistant Staph. aureus, Staph. epidermidis, Staph. pseudintermedius, Staph. saprophyticus, Streptococcus pyogenes, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Candida albicans. A significant reduction in main human dermatophytes including Microsporum canis, M. gypseum, and Talaromyces marneffei of ∼50% was observed (P < .05). Qi hand sanitizer gel inactivated >99% viral particles entering human laryngeal epidermoid carcinoma cells in a dose-dependent manner. Scanning electron micrographs further illustrated that Qi hand sanitizer gel disrupted microbial cell membrane after 1-min contact time resulting in cell death. Qi hand sanitizer gel delivered emollient compounds through simulated human skin layers and showed no cytotoxicity on fibroblast cells. Moreover, Qi hand sanitizer gel demonstrated stability under extreme conditions. CONCLUSIONS: Qi hand sanitizer gel was able to inhibit various microorganisms including bacteria, dermatophytes, and virus.

Silver nanoparticles synthesized from Quercus brantii ameliorated ethanol-induced gastric ulcers in rats by decreasing oxidative stress and improving antioxidant systems.

Gastric ulcers are caused by an imbalance between aggressive and defensive factors. The green synthesis of silver nanoparticles is becoming a new and promising method in the treatment of gastrointestinal ulcers. This study was conducted to investigate the protective and antioxidant effects of silver nanoparticles synthesized from Quercus brantii extract (NSQBE) on gastric damage induced by alcohol in rats. In this study, silver nanoparticles were produced by the green synthesis method using oak extract. The structure and morphology of nanoparticles were confirmed by various techniques such as UV-Vis spectroscopy, fourier transforms infrared spectrometer (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), and dynamic light scattering )DLS(. For the animal studies, 30 male Wistar rats weighing 200 ± 20 g were randomly selected and divided into five groups (the normal, ethanolic, NSQBE treatment (received doses of 20 and 5 mg/kg), and standard (received a dose of 50 mg/kg of ranitidine) groups. After the rats were euthanized, their stomach was removed. A part of the stomach tissue of rats was used for histopathological studies, and the other part was used to study biochemical parameters such as the level of reactive oxygen species (ROS), protein carbonyl oxidation (PCO), malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD) and reduced glutathione (GSH) as well as nitric oxide (NO). Our results showed that in the ethanol group, the levels of ROS, MDA, PCO, and serum NO were higher than in the normal group. In addition, reduced GSH, CAT, SOD, tissue NO, gastric mucus, and antioxidant potential were decreased. In rats pretreated with NSQBE and ranitidine, the levels of ROS, MDA, PCO, and serum NO decreased, and the levels of GSH, CAT, SOD, tissue NO, gastric mucus, and antioxidant potential were increased in comparison to the ethanol group. The results of this study showed that silver nanoparticles synthesized using Quercus brantii are a promising approach for the treatment of gastric ulcers.

Effect of oil extraction on physicochemical and structural properties of starch isolated from acorn (Quercus brantii).

Acorn (Quercus brantii) is a rich source of starch. Since the presence of lipids affects the physicochemical properties of starch and the extraction of nutritious acorn oil and its starch is economical, it's essential to study the acorn starch characteristics before and after oil extraction. Firstly, the best condition for reaching the maximum extraction yield of acorn starch (AS) was determined, and defatted acorn starch (DAS) was extracted in the same conditions. Then the physicochemical properties of both samples were compared. The structural properties were investigated by Scanning Electron Microscopy images. The maximum yield of AS was obtained in a 1:10 ratio (acorn flour: water) at 45 °C and 180 min. Results demonstrated significant differences between color parameters and fat content (0.65 ± 0.04 and 12 ± 0.02) of AS and DAS. Also, DAS had higher swelling power, solubility, and lower turbidity than AS. The X-ray diffraction pattern showed that AS was C-type with relative crystallinity of 27.77 %. Pasting, thermal, and textural properties reflected the higher viscosity, gelatinization, retrogradation, and hardness for DAS compared to AS. Consequently, all of these analyses exhibited structural changes in acorn starch by removing lipids from acorn flour and provided essential information for further applications of acorn starch in different industries.

Formulation, characterization of Quercus infectoria (Olivier) emulsions, and in vitro, in vivo evaluation as cosmeceutical formulation.

BACKGROUND: Pharmacological properties of Quercus infectoria Olivier (galls) have been determined to be astringent, antidiabetic, antipyretic, anti-tremor, local anesthetic, and anti-parkinsonism. The galls of Quercus infectoria have been used for millennia in traditional oriental medicine in Asian nations to treat inflammatory illnesses. AIMS: The study's objective was to create a Quercus infectoria Olivier gall extract in stable water in oil (w/o) emulsion and to check its effects on the mechanical properties of skin and antiaging effects. METHOD: The galls were macerated in absolute methanol. Quercus infectoria Olivier gall extract's antioxidant property was evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) technique. Stearic acid, cetyl alcohol, KOH, glycerin, and distilled water were used to create the emulsion. The test (with extract) and control (without extract) emulsions were made, respectively, using the same process. Stability tests (color, liquefaction, microscopy, phase separation, and pH) are performed in in vitro, lasted 72 days at four distinct storage temperatures that is 8°C, 25°C, 40°C, and 40°C + 75% RH for both the control and test formulations. By using spectrophotometry, the (SPF) sun protection factors of the two formulations were calculated at various concentrations. Extract from Quercus infectoria underwent phytochemical investigation as well. RESULTS: The results showed that Quercus infectoria Olivier has antioxidant and (SPF) sun protection properties, reduce sebum, increases elasticity and stable emulsion containing 04% Quercus infectoria gall extract which might be used as topical antiaging formulation.

Identification of Oak-Barrel and Stainless Steel Tanks with Oak Chips Aged Wines in Ningxia Based on Three-Dimensional Fluorescence Spectroscopy Combined with Chemometrics.

With the increased incidence of wine fraud, a fast and reliable method for wine certification has become a necessary prerequisite for the vigorous development of the global wine industry. In this study, a classification strategy based on three-dimensional fluorescence spectroscopy combined with chemometrics was proposed for oak-barrel and stainless steel tanks with oak chips aged wines. Principal component analysis (PCA), partial least squares analysis (PLS-DA), and Fisher discriminant analysis (FDA) were used to distinguish and evaluate the data matrix of the three-dimensional fluorescence spectra of wines. The results showed that FDA was superior to PCA and PLS-DA in classifying oak-barrel and stainless steel tanks with oak chips aged wines. As a general conclusion, three-dimensional fluorescence spectroscopy can provide valuable fingerprint information for the identification of oak-barrel and stainless steel tanks with oak chips aged wines, while the study will provide some theoretical references and standards for the quality control and quality assessment of oak-barrel aged wines.

The physicochemical properties and Pickering emulsifying capacity of acorn starch.

In this work, the granule characteristics, functional properties, in-vitro digestibility, antioxidant capacity, and phenolic composition of acorn starch were investigated and compared to those of potato starch and corn starch, and its Pickering emulsifying ability was also evaluated. The results showed that the acorn starch granules were spherical and oval in shape, with a smaller particle size, and the amylose content and crystallinity degree were similar to those of corn starch. However, the acorn starch was difficult to swell, with poor aqueous solubility, though it had a strong gel strength and setback viscosity. Because acorn starch contained more free and bound polyphenols, its resistant starch content after cooking and ABTS and DPPH radical scavenging activities were significantly higher than those of potato starch and corn starch. Acorn starch also exhibited outstanding particle wettability and could stabilize Pickering emulsions. The assessed emulsion showed an outstanding effect for protecting ß-carotene against ultraviolet irradiation and was positively correlated with the acorn starch addition amount. The obtained results may serve as a reference for the further development of acorn starch.

Added-Value Compounds in Cork By-Products: Methods for Extraction, Identification, and Quantification of Compounds with Pharmaceutical and Cosmetic Interest.

The growing threat of climatic crisis and fossil fuel extinction has caused a boom in sustainability trends. Consumer demand for so-called eco-friendly products has been steadily increasing, built upon the foundation of environmental protection and safeguarding for future generations. A natural product that has been used for centuries is cork, resulting from the outer bark of Quercus suber L. Currently, its major application is the production of cork stoppers for the wine industry, a process that, although considered sustainable, generates by-products in the form of cork powder, cork granulates, or waste such as black condensate, among others. These residues possess constituents of interest for the cosmetic and pharmaceutical industries, as they exhibit relevant bioactivities, such as anti-inflammatory, antimicrobial, and antioxidant. This interesting potential brings forth the need to develop methods for their extraction, isolation, identification, and quantification. The aim of this work is to describe the potential of cork by-products for the cosmetic and pharmaceutical industry and to assemble the available extraction, isolation, and analytical methods applied to cork by-products, as well the biological assays. To our knowledge, this compilation has never been done, and it opens new avenues for the development of new applications for cork by-products.

Chemical Composition and Bioactivities of Quercus canariensis Flour Acorns Extracts Growing in Tunisia.

The current study was conducted to investigate the chemical composition of Quercus canariensis flour acorns extracts as well as its biological activities in regards to the growing area using spectrophotometric and chromatographic techniques. The phenolic profile was composed of 19 compounds identified through HPLC-DAD analysis. Coumarin was the most abundant compound quantified in BniMtir, Nefza and ElGhorra and gallic (12.58-20.52 %), syringic (4.70-7.64 %) and trans-ferulic (2.28-2.94 %) acids were the abundant phenolic acids while kaempferol was the major flavonoid compounds quantified only in Quercus canariensis growing in BniMtir. On the other hand, Ain Snoussi acorn extract was characterized by its high content in luteolin-7-O-glucoside (58.46 %). The in-vitro antioxidant activities of the studied extracts were investigated and the results showed that Nefza ethanolic extract's has the highest activities. A bactericidal effect against Staphylococcus aureus was observed only by Elghorra population. On the other hand, Ain Snoussi acorn extract was efficient to inhibit growth of pathogenic bacteria, mentioned the highest activity against Escherichia coli. These results is the first study highlighted that zeen oak acorns are an excellent source of natural antioxidants and antibacterial compounds related to their lysozyme activity which could be exploited in the pharmaceutical and food sectors.

Identification of Unstable Ellagitannin Metabolites in the Leaves of Quercus dentata by Chemical Derivatization.

The identification of unstable metabolites of ellagitannins having ortho-quinone structures or reactive carbonyl groups is important to clarify the biosynthesis and degradation of ellagitannins. Our previous studies on the degradation of vescalagin, a major ellagitannin of oak young leaves, suggested that the initial step of the degradation is regioselective oxidation to generate a putative quinone intermediate. However, this intermediate has not been identified yet. In this study, young leaves of Quercus dentata were extracted with 80% acetonitrile containing 1,2-phenylenediamine to trap unstable ortho-quinone metabolites, and subsequent chromatographic separation afforded a phenazine derivative of the elusive quinone intermediate of vescalagin. In addition, phenylenediamine adducts of liquidambin and dehydroascorbic acid were obtained, which is significant because liquidambin is a possible biogenetic precursor of C-glycosidic ellagitannins and ascorbic acid participates in the production of another C-glycosidic ellagitannin in matured oak leaves.

An efficient methodology for modeling to predict wine aroma expression based on quantitative data of volatile compounds: A case study of oak barrel-aged red wines.

Correlating aroma expression with volatile compounds has long been an ambition in researches of flavor chemistry. To propose a reliable methodology to depict wine aroma, 76 oak barrel-aged dry red wines were investigated through the combination of machine learning algorithm and multivariate analysis. Aromatic characteristic was evaluated by quantitative descriptive analysis (QDA), while non- or oak derived volatiles were detected by HS-SPME-GC-MS and targeted SPE-GC-QqQ-MS/MS, respectively. Results showed that variable importance for projection values (VIPs) from partial least-squares regression (PLSR) and mean decrease accuracy (MDA) from random forest were efficient parameters for feature selection. The correlating accuracy of the optimal PLSR model to predict intensities of different aroma characteristics through selected volatile compounds could achieve 0.754 to 0.943, representing potential application to manage wine aroma by chemical assay in winemaking. From the perspective of mathematical modeling in the real wine matrix, the network analysis between aroma characteristics and key volatile compounds indicated that the expression of oak aroma was not only directly contributed by volatiles derived from oak wood, but also influenced by ethyl esters, including ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl decanoate, and ethyl nonanoate.

Identification and Distribution of New Impact Aldehydes in Toasted Oak Wood (Quercus petraea).

The purpose of this study was to identify aroma compounds associated with the toasting intensity of oak wood (Quercus petraea). Crude organic extracts from oak wood samples (toasted at different temperature-time couples) were analyzed by a sensory-guided approach using GC-O-TOFMS, followed by purification with semipreparative HPLC (reverse phase). This approach revealed two specific odorous zones (OZs) reminiscent of metal and puff pastry. The first OZ was identified as trans-4,5-epoxy-(E)-2-decenal (1) by coinjection of the commercial product, whereas identification of (2E,4E,6Z)-nonatrienal (2) associated with puff pastry OZ was validated by a multistep chemical synthesis approach (Wittig reaction) followed by semipreparative HPLC purification (chiral phase). Their detection thresholds in model wine solution were 60 ng/L (1) and 16 ng/L (2). Their distribution in toasted oak wood samples [GC-NCI-MS (NH3) analysis] ranged from some ng/g to 210 ng/g for (1) and 85 ng/g for (2). Finally, additional sensory experiments demonstrated the impact of newly identified aldehydes in toasted oak wood.