Degree Of Oxidation Research Articles

Real-time online monitoring technology for sweeping frequency ultrasound (SFU) assisted extraction of amur grape (Vitis amurensis) seed oil

Sweeping frequency ultrasound (SFU) was used to assist extraction of amur grape (Vitis amurensis) seed (AGS) oil. Extraction conditions and physicochemical properties were optimized and analyzed under different extraction methods. Meanwhile, frequency and time domains were online monitored during SFU assisted extraction of AGS oil. PVDF piezoelectric sensor was used in time domain, and the hydrophone in frequency domain, so as to obtain the time–voltage waveform, signal power, spectrum distribution and other visual models. Physical models of the spatial peak acoustic intensity, charge quantity and work done by electric field force under different ultrasonic conditions were derived. The mathematical model between the work done by electric field force and the spatial peak acoustic intensity under the working state of PVDF piezoelectric sensor was constructed. Results show that the content of AGS oil by SFU assisted extraction was higher than that by organic extraction. Furthermore, the optimal single-frequency was 40 kHz and dual-frequency was 28/33 kHz, and SFU extraction time of 30 min was suitable with higher oil yield of 16.70 % and 16.94 %, respectively. In addition, the selection and combination of SFU also affected the oil oxidation degree. The peak voltage, spatial peak acoustic intensity, signal power and work of electric field force at 28/33 kHz were all higher than those at 40 kHz.

Naturally Occurring Simple Oxygenated Benzophenones: Structural Diversity, Distribution, and Biological Properties

Naturally occurring benzophenones represent a relatively small group of plant metabolites with narrow distribution, mainly in members of Clusiaceae, Gentianaceae, Hypericaceae, Polygalaceae, Myrtaceae, etc.; however, there were reports of several compounds derived from microorganisms belonging to the Aspergillaceae and Valsaceae families and propolis. Benzophenones exhibit many biological activities, such as antioxidant, anti-inflammatory, cytotoxic, antimicrobial, etc. Few reviews on benzophenones that have appeared in the literature were focused on their prenylated derivatives. Summarized information on structural diversity, distribution, and biological activities of simple oxygenated naturally occurring benzophenones and their glycosides has not been found in the literature. Until 2000, only benzophenone C-glycosides were known to occur in nature. Since then, many O-glycosides have been isolated, structurally, and biologically characterized. This review covers the years from 1850 to 2023 and was compiled using databases such as Chemical Abstracts, Scopus, Google Scholar, PubMed, and ResearchGate. Based on their degree of oxidation, 210 chemical structures of benzophenone derivatives and glycosides were grouped into six categories. In addition, in one group of 40 miscellaneous benzophenones, where one or several protons are replaced by a methyl, alcohol, carboxyl, or acyl group, glycosidic forms with such an aglycone and dimeric compounds with xanthone was included. Simple oxygenated benzophenones and their glycosides were found in 77 plant genera belonging to 44 families. The allergy-associated bezophenone-1, benzophenone-2 and benzophenone-3 have limited distribution across natural sources. A wide range of biological activities (antioxidant, anti-inflammatory, cytotoxic, antitumor, cytoprotective, antimicrobial, MAO-A, antiarthritic, anticholinesterase, anti-atherosclerotic, laxative, etc.) of simple oxygenated benzophenones and their glycosides that appeared in the literature were discussed.

Synthesis of acetyl ferulic 7‐hydroxyisoflavone ester and evaluating its antioxidant activity on improving fish oil thermal stability

SummaryAcetyl ferulic 7‐hydroxyisoflavone ester (AHE) was synthesized and its antioxidant capacity in vitro was evaluated by free radical scavenging assay and thermo‐oxidative stability analysis of fish oil in this study. The formation of primary and secondary oxidation products can be effectively inhibited by AHE, tert‐butylhydroxyquinone (TBHQ), ferulic acid and 7‐hydroxyisoflavone. The intensity of UV‐Vis absorption spectra increased significantly, whereas the intensity of fluorescence spectra decreased obviously with the deepening of oxidation degree of fish oil. AHE significantly alleviated the degradation of unsaturated fatty acids in fish oil. The results demonstrated that AHE was more effective than TBHQ, ferulic acid and 7‐hydroxyisoflavone in retarding the oxidative degradation of fish oil during high temperature storage (80 °C). Moreover, the formation of oxidation products in fish oil followed a first‐order kinetic model, and AHE effectively reduced reaction rate constant and delayed secondary lipid oxidation process. As a result, AHE is an effective antioxidant that can stabilise fish oil.

The Adhesion and Moisture Damage Resistance between Castor Oil-Based Bio-Asphalt and Aggregates under the Action of Thermal-Oxidative Aging

This study aims to investigate the adhesion properties and moisture damage resistance between castor oil-based bio-asphalt (COBA) and aggregates under the action of thermal oxidation. Different dosages of castor oil-based bio-oil (5%, 10%, and 15%) were used to prepare the COBA by mixing it with petroleum asphalt. The short-term and long-term aging of COBA were simulated by the rolling thin-film oven test (RTFOT) over 85 min and 385 min, respectively. The boiling method, photoelectric colorimetry, contact angle test, and contact angle moisture susceptibility test (CAMSI) were used to evaluate the adhesion and exfoliation of the COBA–aggregates before and after thermal oxygen aging. Then, the aging degree of COBA was quantitatively evaluated by Fourier transform infrared (FTIR), and the correlation between aging condition and COBA–aggregates adhesion was analyzed. The results showed that the cohesion in COBA increased by 23.1% on average due to the addition of bio-oil. And the adhesion between COBA and aggregates increased by 5% due to the acidic compounds formed in the process of interaction with silicates on the surface of the aggregates. After short-term thermal oxidation, the adhesion between COBA and its aggregates was further improved as the polar components in the asphalt binder increased when the bio-oil dosage was less than 10%. However, with the continuous increase in the bio-oil amount and thermal oxidation degree, the adhesion decreased by 12.6% when compared to the virgin status; in addition, the adhesion grade decreased. Also, a low dosage of bio-oil was found to also improve COBA’s resistance to moisture damage, and helped to reduce moisture sensitivity during the interaction with asphalt binder. However, the acidic compounds that were generated by the reaction with hydrolyzed aggregates in the presence of asphalt binder reduced the adhesion between COBA and the aggregates. Finally, FTIR revealed a good correlation between IC=O and adhesion between COBA and the aggregates.

Raman study of directly synthetized graphene oxide films on Si, SiO2/Si and GaAs by remote-catalyzed CVD

Graphene oxide (GO) is an organic material with interesting properties for nanotechnology. Therefore, it is important to understand the processes that lead to its mass production for deposition onto large-size wafers and with high quality; as well as the control of the number of monolayers and the degree of oxidation. In this work, we propose an alternative method for measuring the oxidation degree of GO. We use simulated Raman spectra from different molecular models that, under computational calculations based on density functional theory (DFT), allow us to explain the measured Raman spectra and the approximate molecular structure of the material. In addition, we report on a methodology based on a process of remotely catalyzed chemical vapor deposition (CVD) to synthesize GO in millimeter areas directly onto three different substrates: SiO2/Si, Si, and GaAs. The results can be used to optimize the synthesis processes of GO and improving the performance of this organic material.

Differentiation of antioxidants in reducing oxidation and improving quality of ready-to-eat roasted shrimp after thermal sterilization

Sterilization is essential for ready-to-eat foods; however, it tends to degrade the quality of the product. To explore the role of antioxidants in regulating the edible quality of roasted Pacific white shrimp after sterilization, color changes, degree of oxidation, microstructure and quality of roasted shrimp treated with tea polyphenols, phytic acid, rosemary extract, and d-sodium erythorbate were investigated. Tea polyphenol-treated roasted shrimp had the lowest Maillard intermediate products and browning strength after sterilization; phytic acid significantly reduced carbonyl content and TBARS value; rosemary extract exhibited the lowest level of free radicals, while d-sodium erythorbate preserved a relatively intact myofibrillar structure. Correlation analysis revealed a negative correlation between the degree of oxidation and the edible quality of roasted shrimp after sterilization. Therefore, the addition of antioxidants inhibited oxidation and improved the quality of roasted shrimp, and different antioxidants had diverse effects on the quality improvement of roasted shrimp after thermal sterilization.

Determination and analysis of macro-featured parameters based on kilogram-level coal spontaneous combustion experiment

The quantitative characterization of coal spontaneous combustion and the accurate determination of the dangerous degree are hot and difficult in the field of coal mine safety. In the paper, the experimental test analysis of Huangling No. 2 coal was carried out by a self-designed and built kilogram-level coal spontaneous combustion experimental device, and the macro featured parameters were obtained and analyzed, such as temperature field, index gas, weight, oxygen consumption rate and exothermic intensity, and spontaneous combustion limit parameters. The results show that the experimental spontaneous combustion period of Huangling No.2 coal is 34 days. When the coal temperature was below the critical temperature of 74.59 °C, the oxidation of coal samples was relatively slow, and the oxygen consumption and the production rate of gas products did not change much. After the coal temperature exceeded the critical temperature, the oxygen consumption rate and exothermic intensity increased faster and the oxidation accelerated. After reaching the dry cracking temperature of 104.93 °C, the oxidation degree accelerated sharply. CO starts to appear at the beginning of the experiment, and the increase of CO gas concentration during the heating process is exponential and can be used as an index gas. Under the temperature condition of 40 °C, the floating coal of 0.7 m needs 25.83% oxygen concentration, and the maximum air leakage intensity of the coal is negative, and no spontaneous combustion will occur. The test data and calculation results of the experiment are important for the prediction and forecast of natural fires and the determination of the risk of spontaneous combustion on site.

Heat shock pretreatment and low temperature fluctuation cold storage maintains flesh quality and retards watercore dissipation of watercored 'Fuji' apples

Watercored apples have a unique flavor and particular flesh morphology. However, watercored apples are subject to loss of water core, browning, and softening during postharvest storage. In this study, heat shock pretreatment, hot air (HA) or hot water (HW), was combined with low temperature fluctuation (LTF) cold storage to delay the disappearance of the water cores and the flesh browning and softening during a 120 d storage. The apples were evaluated for appearance characteristics, texture parameters, enzyme activities, reactive oxygen content, membrane lipid oxidation degree, tissue microstructure, and cell morphology during the storage period. The results showed that HW combined with LTF was most effective in maintaining the visual quality and texture quality of watercored apples compared with other treatments and the control. Moreover, HW-LTF could effectively inhibit the accumulation of malondialdehyde (MDA), retard the increase of electrolyte leakage (EL), reduce the membrane lipid peroxidation, and maintain the tissue microstructure and cell morphology. Meanwhile, HW-LTF inhibited the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) and reduced the degree of flesh browning. Therefore, the HW-LTF is of guiding significance for the cold storage of watercored apples.

Systematic assessment of the silk deterioration behaviors for silk aging prediction

The silk cultural artifacts have suffered significant deterioration since their discovery, and the unsuitable conditions in the storage environment will further exacerbate this degradation. Systematically and quantitatively assessing the degree of deterioration of silk fabrics with multiple indexes is imperative. In this study, color difference, oxidation degree, crystallinity, and amino acid contents were employed to investigate the aging degradation process of silk fabrics. The results illustrated that both thermal and ultraviolet aging processes were accompanied by discoloration, increasing oxidation degree, decreasing crystalline degree, and amino acid contents reduction. Moreover, the aging level of silk fabrics deterioration behaviors varied across three different stages: (i) the initial stage was primarily marked by color changes, (ii) while oxidation degree and crystallinity alterations dominated in the intermediate phase, (iii) and a substantial reduction in amino acid contents prevailed during the final stage of aging. Therefore, the color difference could be identified as the early safety warning indicator for cultural relics preservation. The GM (1, 1) and GNNM (1, 1) forecasting models were utilized and the results suggested that GNNM (1, 1) outperformed GM (1, 1) in predicting the color properties of silk fabrics, indicating its potential for widespread use in predicting the deterioration of silk artifacts within collections. Collectively, this work comprehensively investigated the degradation process of silk fabrics and further achieved the prediction of color property changes during the simulated aging process, thereby providing a theoretical foundation for the conservation and protection of silk fabrics.

Supergene Hydrous Sulfates in the Tuolugou Co-Au Deposit, Northern Qinghai–Tibet Plateau: Implications for Genetic Mechanism and Exploration

Supergene hydrous sulfate minerals form through the oxygenation and weathering of primary sulfides. In the Qinghai–Tibet Plateau region, with an alpine and dry environment, hydrous sulfate minerals oxidized from pyrite-bearing ore bodies provide important clues regarding the mineralization and environment. The Tuolugou sedimentary-exhalative (SEDEX) Co-Au deposit is located in the East Kunlun metallogenic belt of the northern Qinghai–Tibet Plateau in China. In the mining district, pyrite is the prevalent Co-hosting sulfide mineral, and is partially exposed on the surface to weathering and oxidation. Herein, we document the mineral assemblages in the supergene oxidation zone in the Tuolugou deposit, probe the genesis of supergene assemblage, and explore the implications for exploration. Three zones can be recognized in the oxidation zone of the Tuolugou deposit, including the outer zone (natrojarosite), intermediate zone (rozenite and aplowite), and inner zone (roemerite and melanterite). The mechanism of oxidation under aerobic and anaerobic conditions, as well as zoning with different oxidation degrees, are described in detail. Hydrous sulfates such as natrojarosite can be used as possible indicators of the exploration of albitite-related SEDEX deposit in this region.

Tailoring the performance of composite PEI nanofiltration membranes via incorporating activated cyclodextrins

Cyclodextrins (CDs) with unique cavity structures have been used as materials for nanofiltration membrane fabrications. In the present work, the activated CD (O-CD), oxidated by NaIO4, and polyethyleneimine (PEI) were co-deposited on a hydrolyzed polyacrylonitrile support, post-treated by glycerol protection and heating treatment, to prepare nanofiltration membranes with low molecular weight cut-off (MWCO). As the cavities in CD present and the aldehyde groups introduced after oxidation, the O-CDs were expected to crosslink the PEI layer and provide extra permeating channels. The filtration experiments showed that the incorporation of O-CDs improved the permeances of the O-CD-PEI/HPAN nanofiltration membranes. The performance can be tailored by the control of the loading or the oxidation degree of the O-CD. At optimal conditions, the permeance increment was nearly double (from 9.2 to 21.1 Lm-2·h−1·bar−1). While the selectivity was without significant sacrifice, the rejection of PEG 200 remained around 90%. Meanwhile, the membrane stability was demonstrated by pro-longed filtratiing a PEG 200 aqueous solution. The constant permeance and rejection confirmed the O-CD-PEI/HPAN membranes were stable. The incorporation of activated CD in PEI offers a facile strategy to promote the permeance of PEI-based membranes.

Structure and surface properties of ozone-conjugated octenyl succinic anhydride modified waxy rice starch: Towards high-stable Pickering emulsion

In the present work, a dual-modified waxy rice starch (OOWRS) fabricated with OSA and ozone was successfully used to stabilize the O/W Pickering emulsion. The molecular structure, surface properties, and underlying stabilizing mechanism were systematically investigated. The results showed that oxidation occurring on the surface of OSA-modified waxy rice starch (OSAWRS) resulted in the presence of indentations and cracks. The relative crystallinity of starch was generally decreased with increasing degree of oxidation. Due to the introduction of carbonyl and the variation in surface structure, the hydrophobicity and acidity of OSAWRS were significantly enhanced after the ozone treatment. Remarkably, OOWRS stabilized Pickering emulsion exhibited a feature of typical O/W emulsion, and the 0.5 h and 1 h OOWRS emulsion exhibited a more uniform droplet size as well as a higher surface potential. We also noted that a weak-gel network was formed within the OOWRS emulsion system as the hydrophilic starch chains played a bridging role. Two reasons for the improved stability of the emulsion were the special gel structure and the enhanced electrical repulsion among the droplets. This research provides that ozone-conjugated OSA modification is a promising strategy for improving the emulsion ability of starch-based Pickering emulsions.

Variation in the bandgap by gradual reduction of GOs with different oxidation degrees: A DFT analysis

The bandgap of two-dimensional graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO) materials is modified by the gradual incorporation and removal of functional groups on the surface of the material. In this work, using Density Functional Theory (DFT) with BIOVIA Materials Studio software, the variation of the bandgap of GO and rGO as a function of the O/C ratio has been studied. The direct relationship between the bandgap and the number of epoxide functional groups in the GO is demonstrated. A gradual increase in the bandgap from 0.211 to 3.58 eV was observed by varying the O/C ratio from 0.06 to 0.50. In the range of O/C ratios from 0.17 to 0.28, the bandgap decreased, estimating the lowest value of 0.0211 eV at O/C = 0.22 despite the increased functional groups in the material. This phenomenon is explained by the balance between the number of sp2 conducting states and the loss of linearity of the sheets due to the incorporation of functional groups. On the other hand, the GOs were reduced by gradually removing their functional groups at different O/C ratios, ranging from 0.50 to the total elimination of the epoxide functional groups. This study showed that the bandgap of the now-called rGOs varies according to two parameters: (i) the number of functional groups to be eliminated in a GO (reduction process) and (ii) the number of functional groups present in the GO to be reduced. This theoretical study has calculated the existence of multiple bandgaps in these materials, finding the most significant difference in the O/C ratio=0.33, estimating bandgaps of 0.50 eV and 1.82 eV, for rGO and GO, respectively, thus raising the need to be more specific in their denomination. Finally, the use of a nomenclature based on subscripts a, b, c, and d, describing the number of layers, the type of functional group, the number of functional groups added (in GO), and the number of functional groups removed in rGO, respectively, has been proposed.

Effects of dissolved organic matter removal and molecular transformation in different water treatment processes on formation of disinfection byproducts

Alterations in molecular composition of dissolved organic matter (DOM) during water treatments can influence the composition and toxicity of disinfection by-products (DBPs) in subsequent chlorination disinfection process. In this study, the impacts of DOM composition after various water treatment techniques (coagulation, adsorption, nanofiltration, biological aerated filter (BAF), and their integrated processes) on the generation mechanisms of DBPs were comprehensively explored by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in combination with GC–MS and LC-MS analysis. The results indicated that coagulation preferentially removed unsaturated (low H/C) and oxidized (high O/C) compounds, whereas adsorption was prone to remove the reduced (low O/C) component that was more reactive with chlorine, leading to lower yields (μg DBP/mg DOC) of trihalomethanes (THMs) and haloacetic acids (HAAs) during subsequent chlorination. The coagulation-adsorption technique exhibited a relatively high removal of both known and unknown DBPs, demonstrating that coagulation and adsorption were complementary for DOM removal at the molecular level. Nanofiltration selectively removed molecules with relatively high O/C, however, those with very low O/C that were more reactive with chlorine could pass through the nanofiltration membrane, resulting in the highest yields of THMs and HAAs. Although BAF was inefficient in removing DBPs precursors, it could convert molecules with low degree of oxidation and unsaturation into highly oxidized and unsaturated ones, thereby significantly enhancing the removal of DBPs precursors in the subsequent coagulation-adsorption process. These findings are instrumental in developing and selecting more effective techniques to minimize the formation of DBPs in water treatment.

Detailed investigation and influence of oxidation degree on synthesis, characterization and antibacterial activity of β- cyclodextrin

Oxidation of β-cyclodextrin (β-CD) using varying molar ratios of sodium periodate (NaIO4) was investigated in detail on synthesis, characterization and antibacterial property. Synthesis and characterization results showed that Oxidized β-cyclodextrins (OX-β-CDs) were obtained and aldehyde (CHO) groups were successfully introduced. Our results demonstrated that aldehyde content and yield increased with increasing NaIO4 molar amount. However, the structure of β-CD was degraded as a result of glycosidic ring opening with increasing stoichiometric ratio of NaIO4/β-CD to 5/1 and 7/1.Aldehyde functional groups in OX-β-CDs were characterized by employing FTIR, 1H NMR, XRD, SEM techniques and confirmed by the detection of CHO peak at 1730 cm-1 in the FTIR and detection of the aldehyde H peak between 9 to 10 ppm in the 1H NMR spectrum. In addition, SEM and XRD of OX-β-CDs showed alterations in the morphological and crystal structure (transforming from crystalline to amorphous) of β-CD as a result of increasing oxidation.Especially, antibacterial activity of OX-β-CDs was investigated against both Gram-negative and Gram-positive bacteria by using the minimal inhibitory concentration (MIC) and the Disk diffusion method. The results showed that OX-β-CDs possessed good antibacterial activity, which can destroy the bacterial cell wall, and may be used as an antibacterial agent.

Facile preparation of carbon dots with multicolor emission for fluorescence detection of ascorbic acid, glutathione and moisture content

The nitrogen-doped carbon dots (N-CDs) with multicolor emission (green, yellow, and red) were fabricated with naphthalenetetracarboxylic dianhydride as carbon precursor, and different alkylamines as passive agents. The structures of the as-prepared carbon dots were confirmed by the Fourier transform infrared (FT-IR) spectrum, X-ray photoelectron spectroscopy (XPS) spectra, transmission electron microscopy (TEM), Raman spectra, and X-ray diffraction (XRD) pattern. The characterized results and UV–vis absorption spectrum demonstrated that the luminescence variations of different CDs were probably attributed to the difference of N-related states, oxygen-containing groups, and oxidation degree in the CDs structure. Moreover, the green emitting CDs (G-CDs) could be utilized as fluorescent probe for ascorbic acid (AA) detection with detection limit (LOD) of 5 μM. The yellow emitting CDs (Y-CDs) could be used to detect glutathione (GSH) in the range of 1–70 μM with LOD of 0.07 μM. The red emitting CDs (R-CDs) could detect the water content in THF, DMF, acetone, and EtOH with LODs of 0.44%, 0.31%, 0.55% and 0.55%, respectively. Remarkably, G-CDs and Y-CDs can distinguish AA and GSH respectively with high selectivity and accuracy. Finally, the fluorescent probes based on G-CDs and Y-CDs were successfully applied for the AA and GSH determination in vitamin C tablet, grapefruit juice, and GSH whitening serum samples with high reliability and feasibility, which provided the guidance for the selection of AA and GSH supplements.

Humic-like Substances (HULIS) in Ship Engine Emissions: Molecular Composition Effected by Fuel Type, Engine Mode, and Wet Scrubber Usage.

Humic-like substances (HULIS), known for their substantial impact on the atmosphere, are identified in marine diesel engine emissions obtained from five different fuels at two engine loads simulating real world scenarios as well as the application of wet sulfur scrubbers. The HULIS chemical composition is characterized by electrospray ionization (ESI) ultrahigh resolution mass spectrometry and shown to contain partially oxidized alkylated polycyclic aromatic compounds as well as partially oxidized aliphatic compounds, both including abundant nitrogen- and sulfur-containing species, and clearly different to HULIS emitted from biomass burning. Fuel properties such as sulfur content and aromaticity as well as the fuel combustion efficiency and engine mode are reflected in the observed HULIS composition. When the marine diesel engine is operated below the optimum engine settings, e.g., during maneuvering in harbors, HULIS-C emission factors are increased (262-893 mg kg-1), and a higher number of HULIS with a shift toward lower degree of oxidation and higher aromaticity is detected. Additionally, more aromatic and aliphatic CHOS compounds in HULIS were detected, especially for high-sulfur fuel combustion. The application of wet sulfur scrubbers decreased the HULIS-C emission factors by 4-49% but also led to the formation of new HULIS compounds. Overall, our results suggest the consideration of marine diesel engines as a relevant regional source of HULIS emissions.

Determining the Role of Oxygen in Obtaining Long-Term Stable Superhydrophilic Surfaces on Metals Treated with a Femtosecond Laser.

Laser processing is a simple way to obtain hydrophobic or even superhydrophobic properties of metal surfaces. However, preparation of superhydrophilic surfaces by this method, the properties of which do not change under the influence of various factors, remains a difficult task. In this work, we show that with increasing laser power, the degree of oxidation of the treated metal surface also increases. As a result, highly oxidized samples showed highly stable superhydrophilic properties. A Janus membrane fabricated from a stainless steel mesh with asymmetric hydrophilic-hydrophobic wettability demonstrated stable water diode properties. In addition, it was found that during the examination of sample surfaces by Raman spectroscopy, organic compounds adsorbed on the hydrophobic surface were decomposed by the laser of the spectrometer, which imposes limitations on the laser power when using this method in characterizing hydrophobic surfaces of metals fabricated by laser processing.

Sous vide cooking improved the physicochemical parameters of hot-boned bovine semimembranosus muscles

The physicochemical parameters of hot-boned bovine semimembranosus muscles after sous vide cooking were investigated. Hot-boned or wet-aged steaks were collected, and cooked by different cooking methods, including sous vide (57 °C, 11 h, SV), grilling (at 200 °C to the central temperature of 72 °C, GR) or boiling (100 °C, 2 h, BO). The meat color, tenderness, water-holding capacity, degree of oxidation, myoglobin denaturation and sensory quality traits were determined, as well as the changes in the microstructure. Compared to other cooking methods, SV reduced the degree of oxidation and muscle shortening, and significantly improved the water holding capacity (WHC), tenderness, connective tissue content and overall acceptability for both hot-boned and wet-aged steaks. The oxidation and muscle shortening were reduced in hot-boned SV steaks (P < 0.05), and the water-holding capacity and sensory scores for juiciness, connective tissue content and overall acceptability were increased (P < 0.05) compared to the wet-aged steaks. The combination of hot-boning and SV cooking resulted in an acceptable tenderness, better overall sensory acceptability and higher WHC than other combinations of muscle states and cooking methods. Therefore, it is a good choice to cook hot-boned semimembranosus muscles using SV to improve the eating quality, which can eliminate the need for aging, benefiting the beef industry.

Lichen as Bioindicators: Assessing their Response to Heavy Metal Pollution in Their Native Ecosystem

Lichens play crucial roles in the ecosystems, contributing to soil formation and nutrient cycling, and being used in biomonitoring efforts to assess the sustainability of ecosystems including air quality. Previous studies on heavy metal accumulation in lichens have mostly relied on manipulated environments, such as transplanted lichens, leaving us with a dearth of research on how lichens physiologically respond to heavy metal exposure in their natural habitats. To fill this knowledge gap, we investigated lichens from two of South Korea’s geographically distant regions, Gangwon Province and Jeju Island, and examined whether difference in ambient heavy metal concentrations could be detected through physiological variables, including chlorophyll damage, lipid oxidation, and protein content. The physiological variables of lichens in response to heavy metals differed according to the collection area: Arsenic exerted a significant impact on chlorophyll degradation and protein content. The degree of fatty acid oxidation in lichens was associated with increased Cu concentrations. Our research highlights the value of lichens as a bioindicator, as we found that even small variations in ambient heavy metal concentrations can be detected in natural lichens. Furthermore, our study sheds light on which physiology variables that can be used as indicators of specific heavy metals, underscoring the potential of lichens for future ecology studies.