Aldehyde Content Research Articles

Combined of plasma-activated water and dielectric barrier discharge atmospheric cold plasma treatment improves the characteristic flavor of Asian sea bass (Lates calcarifer) through facilitating lipid oxidation

To explore the combination effects of plasma-activated water and dielectric barrier discharge (PAW-DBD) cold plasma treatment on the formation of volatile flavor and lipid oxidation in Asian sea bass (ASB), the volatile flavor compounds and lipid profiles were characterized by gas chromatography-ion mobility spectrometry and LC-MS-based lipidomics analyses. In total, 38 volatile flavor compound types were identified, and the PAW-DBD group showed the most kinds of volatile components with a significant (p < 0.05) higher content in aldehydes, ketones, and alcohols. A total of 1500 lipids was detected in lipidomics analysis, phosphatidylcholine was the most followed by triglyceride. The total saturated fatty acids content in PAW-DBD group increased by 105.02 μg/g, while the total content of unsaturated fatty acids decreased by 275.36 μg/g. It can be concluded that the PAW-DBD processing increased both the types and amounts of the volatile flavor in ASB and promoted lipid oxidation by altering lipid profiles.

Evaluation of Loquat Jam Quality at Different Cooking Times Based on Physicochemical Parameters, GC-IMS and Intelligent Senses.

The study compared and analyzed the quality of loquat jam with different cooking times through physicochemical parameters, headspace-gas chromatography-ion migration spectroscopy (HS-GC-IMS) and intelligent senses. The results showed that with the prolongation of the cooking time, the color of loquat jam slowly deepened, the energy significantly increased, the adhesiveness, gumminess, hardness and chewiness enhanced, the free amino acid content increased from 22.40 to 65.18 mg/g. The organic acid content increased from 1.64 to 9.82 mg/g. Forty-seven volatile flavor compounds were identified in five types of loquat jam using HS-GC-IMS, among which the relative content of aldehydes was sharply higher than that of other chemical substances, playing an important role in the flavor formation of loquat jam. LJ0, LJ1 and LJ2 had higher aldehyde content, followed by LJ3 and LJ4 had the lowest aldehyde content. The orthogonal partial least squares-discriminant analysis (OPLS-DA) screened 15 marker compounds that could distinguish five types of loquat jam. The E-nose results showed a significant difference in olfactory sense between loquat jam cooked for 100 and 120 min. The E-tongue results corroborated the results of free amino acids (FAAs) and organic acids, indicating that the gustatory sense of loquat jam changed significantly when the cooking time reached 120 min. The results provided a basis for further research on the relationship between the cooking process and quality characteristics of loquat jam.

Effect of swelling agent treatment on grape fruit quality and the application of electronic nose identification detection.

The swelling agent is a plant growth regulator that alters the composition and content of nutrients and volatile gases in the fruit. To identify whether grape fruit had been treated with swelling agent, the odor information and quality indexes of grape berries treated with different concentrations of swelling agent were examined by using electronic nose technology and traditional methods. The contents of soluble sugars, soluble solids, soluble proteins and vitamin C were significantly increased in N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) treated fruit. The contents of hexanal, (E)-2-hexenal, and nonanal aldehydes decreased significantly. Similarly, the levels of phenyl ethanol, 1-octanol, ethanol, and ethyl acetate alcohols and esters also decreased noticeably. Additionally, the levels of damascenone, linalool, and geraniol ketones and terpenoids decreased. However, the contents of benzaldehyde, D-limonene, acetic acid and hexanoic acid increased. In addition, the electrical signals generated by the electronic nose (e-nose) were analyzed by linear discriminant analysis (LDA), support vector machine (SVM) and random forest (RF). The average recognition rate of SVM was 94.4%. The results showed that electronic nose technology can be used to detect whether grapes have been treated with swelling agent, and it is an economical and efficient detection method.

Effects of different pickling methods on physicochemical properties and flavor profiles of Tongling white ginger: Dry-salting, brine-pickling, and inoculation-pickling.

Tongling white ginger is a Chinese fermented vegetable with unique flavors. However, little is known about its physicochemical properties, flavor characteristics, and sensory evaluation. The study examined the physicochemical (pH, titratable acidity [TA], nitrite, soluble protein, and color) and flavor characteristics (organic acids, free amino acids, and volatiles) of white ginger during fermentation. The results showed that the pH value and soluble protein in the dry-salted, brine-pickled, and inoculation-pickled decreased significantly while the TA value increased significantly, inoculation-pickled can effectively reduce the content of nitrite. After fermentation, inoculation-pickled produced the highest content of organic acids, while dry-salted produced the highest total amount of free amino acids. A total of 70, 68, 70, and 69 volatile compounds were identified in fresh, dry-salted, brine-pickled, and inoculation-pickled white ginger. The total contents of terpenoids of Tongling white ginger by three fermentation methods decreased; the total contents of alcohols and aldehydes were the highest in brine-pickled, and esters and ketones were more abundant in inoculation-pickled. The results showed that inoculation-pickled could shorten the fermentation time of Tongling white ginger, produce a unique flavor, and have the highest sensory score.

Effects of juicing methods on the bioactive compounds and flavor quality of 'Black-seed' pomegranate from three producing areas.

Color, nutrients and flavor are the key characteristics of pomegranate juice, but they are susceptible to processing methods and raw materials. In this study, the effects of aril juicing and whole fruit juicing methods on the composition of 'Black-seed' pomegranate juice from three producing areas were studied, including physicochemical parameters, color attributes, organic acids, sugars, phenolic compounds, and volatile compounds. The whole fruit juicing method resulted in higher juice yields of pomegranate fruit with 69.01-72.59%, hue angle values were 5.95-6.45°, and the juice remained red. The highest level of citric acid (21.21 g L-1 ), total acids (24.78 g L-1 ), and total anthocyanin content (435.59 mg L-1 ) were found in whole fruit juice, and seven tannins were detected. The most abundant volatile compounds were (Z)-3-hexen-1-ol and 1-hexanol in all juice samples, with alcohol content increased and aldehydes content decreased by whole fruit juicing. Principal component analysis revealed that the 24 indexes (variable important in projection >1) clearly distinguished juice samples obtained by two juicing methods, with ellagic acid hexoside, (E)-2-heptenal, (+)-catechin, and octanoic acid having the best discriminatory potential. Overall, the effects of juicing method on 'Black-seed' pomegranate juice were greater than those of raw-material-producing areas. These results confirmed the potential for using the whole 'Black-seed' pomegranate for processing, and also provided a theoretical basis for the healthy product development and utilization of dark-color pomegranate varieties. © 2023 Society of Chemical Industry.

Transcriptomic Insights into the Enhanced Aroma of Guangdong Oolong Dry Tea (Camellia sinensis cv. Yashixiang Dancong) in Winter.

Winter dry tea (WDT) exhibits a more intense and lasting aroma compared to dry tea from other seasons; however, this conclusion is solely based on sensory outcomes and lacks corroborative theoretical evidence. Our study aimed to analyze the aroma compounds in WDT and investigate the causes behind the formation of WDT's aroma by analyzing the volatile organic compounds (VOCs) in WDT, spring dry tea (SDT), winter fresh leaves (WFLs) and spring fresh leaves (SFLs) by gas chromatography-mass spectrometry (GC-MS), complemented by an analysis of gene expression pertinent to WFLs and SFLs by using transcriptomic analysis. The results revealed a significant increase in total VOCs in WDT compared to SDT, with WDT exhibiting distinct woody aromas as indicated by a higher α-muurolene content. In WFL, the contents of aldehydes and ketones were richer than those in SFL. Notably, the study found that UDP-glycosyltransferase genes in WFLs were significantly up-regulated, potentially promoting the synthesis of terpene glycosides. These terpene glycosides can release terpene aroma compounds during processing, contributing significantly to the intense and lasting aroma of WDT. Overall, this research provides valuable insights into the mechanism behind aroma formation in Guangdong oolong tea harvested during winter.

Effect of cherry products addition on beer fermentation

Fruits has been used in brewing as a source of sugars, colour and flavour. Cherry (Prunus avium L.) products such as juice and pomace can be used in brewing in order to increase beer biological value. In this study, cherry juice and pomace in concentration of 15 % were added at first and seventh day of beer fermentation. The effect of cherry products addition was investigated by measuring the content of yeast metabolites (ethanol, aldehydes, higher alcohols, esters, and vicinal diketones) in cherry beers and control sample without cherries. The alcohol content in all the cherry beers was higher than the control sample. The cherry juice addition at the beginning of fermentation led to the formation of more secondary metabolites than the control. Cherry juice addition at the seventh day of fermentation resulted in a decrease in higher alcohols and esters concentration, but in an increase in carbonyls concentration compared to the control. Cherry pomace addition led to a significant increase in esters and vicinal diketones concentration. Aldehydes concentration was not affected by cherry pomace addition. Higher alcohols were influenced only by pomace addition at the seventh day of fermentation. Sensory evaluation was also made because yeast metabolites affected beer flavour and aroma.

The influence of raw materials on the biochemical profile of distillates

This study focuses on exploring novel ingredients for the production of safe, high-quality alcoholic beverages and enhancing the processes involved in fermenting beverages. These efforts aim to support local community development initiatives targeting food security, food sovereignty, and small businesses. The article presents the technology for producing distillates from vegetative raw materials, integrating digital technologies for quality control across all manufacturing stages. Distillates were obtained using the “Minispirtzavod Simpl 2018 set “Authentic” equipment, featuring remote control capabilities and a built-in Wi-Fi module. The quality of distillates derived from various vegetable raw materials, including grapes, apples, wheat, and birch sap, was evaluated through organoleptic analysis, assessing appearance, aroma, and taste. Gas chromatography was employed to determine the content of ethyl alcohol, furfural, methyl alcohol, aldehydes, ethers, and fusel alcohol in the distillates. The resulting distillates contained 40.9% to 43.5% vol.% ethanol and exhibited distinct aromatic profiles and flavors based on the vegetative raw material used. This diversity offers opportunities to expand the range of alcoholic products available.

Catalytic pyrolysis and in situ carbonization of walnut shells: poly-generation and enhanced electrochemical performance of carbons.

In this study, walnut shell (WS) was used as feedstock, incorporating lithium carbonate (LC), sodium carbonate (SC), potassium carbonate (PC), and potassium hydroxide (PH) as pyrolysis catalysts and carbonization activators. A one-step method that allows catalytic pyrolysis and carbonization to be carried out consecutively under their respective optimal conditions is employed, enabling the concurrent production of high-quality pyrolysis oil, pyrolysis gas, and carbon materials from biomass conversion. The effects of LC, SC, PC, and PH on the yield and properties of products derived from WS pyrolysis as well as on the properties and performance of the resulting carbon materials were examined. The results indicated that the addition of LC, SC, PC, and PH enhanced the secondary cracking of tar, leading to increased solid and gas yields from WS. Additionally, it increased the production of phenolic compounds in bio-oil and H2 in syngas, concurrently yielding a walnut shell-based carbon material exhibiting excellent electrochemical performance. Specifically, when PC was used as an additive, the phenolic content in the pyrolysis oil increased by 27.64% compared to that without PC, reaching 74.9%, but the content of ketones, acids, aldehydes, and amines decreased. The hydrogen content increased from 2.5% (without the addition of PC) to 12.75%. The resulting carbon (WSC-PC) displayed a specific surface area of 598.6 m2 g-1 and achieved a specific capacitance of 245.18 F g-1 at a current density of 0.5 A g-1. Even after 5000 charge and discharge cycles at a current density of 2 A g-1, the capacitance retention rate remained at 98.16%. This method effectively enhances the quality of the biomass pyrolysis oil, gas, and char, contributing to the efficient and clean utilization of biomass in industrial applications.

Study on simulation effect of physical and chemical characteristics of sausage by sausage model system.

The incorporation of Staphylococcus xylosus in sausage production is hypothesized to affect various physicochemical properties and flavor profiles of sausages. This study aimed to evaluate the simulation of these features in a sausage model and establish its applicability for in vitro studies. Both a control and an experimental model, inclusive of Staphylococcus xylosus, were assessed for changes in physicochemical indexes (pH and water activity, Aw) and the concentration of flavoring components (esters and aldehydes). Thiobarbituric acid reactive substances (TBARS) values were also measured to evaluate lipid oxidation. The introduction of Staphylococcus xylosus resulted in no significant changes in pH and Aw between the sausage and the model. However, there was a considerable increase in the content of volatile flavor compounds, specifically esters and aldehydes, in the experimental groups compared to the control. Additionally, the TBARS values in experimental groups were significantly lower than those in the control group at the end of the testing period. The findings indicate that Staphylococcus xylosus plays a critical role in enhancing the flavor profile of sausages through the increased synthesis of volatile compounds and inhibiting fat oxidation. The sausage model effectively simulated the physicochemical and flavor index responses, demonstrating its potential utility for further in vitro research on sausage fermentation and preservation techniques.

Comparison of simultaneous saccharification and fermentation with LPMO-supported hybrid hydrolysis and fermentation.

Enzymatic saccharification is used to convert polysaccharides in lignocellulosic biomass to sugars which are then converted to ethanol or other bio-based fermentation products. The efficacy of commercial cellulase preparations can potentially increase if lytic polysaccharide monooxygenase (LPMO) is included. However, as LPMO requires both a reductant and an oxidant, such as molecular oxygen, a reevaluation of process configurations and conditions is warranted. Saccharification and fermentation of pretreated softwood was investigated in demonstration-scale experiments with 10m3 bioreactors using an LPMO-containing cellulase preparation, a xylose-utilizing yeast, and either simultaneous saccharification and fermentation (SSF) or hybrid hydrolysis and fermentation (HHF) with a 24-hour or 48-hour initial phase and with 0.15 vvm aeration before addition of the yeast. The conditions used for HHF, especially with 48h initial phase, resulted in better glucan conversion, but in poorer ethanol productivity and in poorer initial ethanol yield on consumed sugars than the SSF. In the SSF, hexose sugars such as glucose and mannose were consumed faster than xylose, but, in the end of the fermentation >90% of the xylose had been consumed. Chemical analysis of inhibitory pretreatment by-products indicated that the concentrations of heteroaromatic aldehydes (such as furfural), aromatic aldehydes, and an aromatic ketone decreased as a consequence of the aeration. This was attributed mainly to evaporation caused by the gas flow. The results indicate that further research is needed to fully exploit the advantages of LPMO without compromising fermentation conditions.

Deciphering polymer degradation chemistry via integrating new database construction into suspect screening analysis.

Water-soluble synthetic polymers and their environmental degradation products are overlooked but important industrial pollutants in wastewater. However, the detection of degradation products is limited to bulk solution chemistry and molecular-level analysis remains unreachable. In this work, we assessed the feasibility of current suspect screening and nontarget workflow using liquid chromatography-high resolution mass spectrometry (LC-HRMS) to elucidate molecular level information about polyacrylamide (PAM) and its degraded products by free radicals. Radical chain scission of PAM (10 kDa) using heat-activated persulfate was conducted to simulate hydraulic fracturing conditions in the deep subsurface. We found that the current workflows in the commercial software generated predicted formulae with low accuracy, due to limited capability of peak picking and formula prediction for high mass and charge features. By modeling literature-reported degradation pathways, we constructed a degradation product database of over 463 000 unique formulae, which improved the accuracy of the predicted formula. For the matched features, the ratio of aldehyde/ketone terminating molecule abundance was found to increase over 24 h degradation time, suggesting increasing content of aldehydes by radical-induced oxidative chain scission of PAM. This is contradictory to previously proposed ratios of carbon-centered radical position on polymer backbone initiated by hydroxyl radicals. Using in silico fragmentation of MS1 features, we identified 11 structures with confidence levels 2b and 3 using their MS2 information. This is the first attempt to resolve complex polymer degradation chemistry using HRMS that can advance our ability to detect water-soluble polymer pollutants and their transformation products in environmental samples.

Tunable fluorescent probes for detecting aldehydes in living systems.

Aldehydes, pervasive in various environments, pose health risks at elevated levels due to their collective toxic effects via shared mechanisms. Monitoring total aldehyde content in living systems is crucial due to their cumulative impact. Current methods for detecting cellular aldehydes are limited to UV and visible ranges, restricting their analysis in living systems. This study introduces an innovative reaction-based trigger that leverages the exceptional selectivity of 2-aminothiophenol for aldehydes, leading to the production of dihydrobenzothiazole and activating a fluorescence response. Using this trigger, we developed a series of fluorescent probes for aldehydes by altering the fluorophore allowing for excitation and emission wavelengths across the visible to near-infrared spectral regions without compromising the reactivity of the bioorthogonal moiety. These probes exhibit remarkable aldehyde chemoselectivity, rapid kinetics, and high quantum yields, enabling the detection of diverse aldehyde types, both exogenous and endogenous, within complex biological contexts. Notably, we employed the most red-shifted near-infrared probe from this series to detect aldehydes in living systems, including biliary organoids and mouse organs. These probes provide valuable tools for exploring the multifaceted roles of aldehydes in biological functions and diseases within living systems, laying the groundwork for further investigations.

Retarding sunflower oil oxidation during the deep-fat frying of potato chips using micro-encapsulated Convolvulus arvensis Linn leaf phenolic extract

In this research, the extraction of polyphenols from Convolvulus arvensis (CA) leaves was optimized using ethanol (80%) at plant/solvent ratios and extraction times which varied between 1/10 to 1/30 (w/v) and 20 to 120 min, respectively. The extract with the highest polyphenol content was obtained at a ratio of 1/30 and 90 min. At 120 ppm, the preceding extract in either lyophilized (LyCAE) or encapsulated (EnCAE) form was evaluated as an antioxidant during the frying process using sunflower oil in comparison to TBHQ. Frying oil quality indices including refractive index, smoke point, acid value, anisidine value, polar and polymer compounds were monitored throughout frying times. FTIR spectroscopy was used to investigate the changes in trans-fatty acids, hydroperoxides and aldehyde contents. The results showed that the phenolic extract, especially in EnCAE form, exhibited superior antioxidant activity over TBHQ, which consequently led to the utilization of this phenolic extract as an antioxidant in frying oils.

The Preparation and Performance of Bamboo Waste Bio-Oil Phenolic Resin Adhesives for Bamboo Scrimber

Bamboo is a fast-growing plant with properties such as low cost, abundant resources, and good carbon sequestration effect. However, the swift growth of bamboo resources generates an immense quantity of processing waste, which is necessary to effectively utilize bamboo processing waste. The leftovers from bamboo processing can be reutilized by fast pyrolysis to prepare renewable bio-oil. In this study, bamboo bio-oil was partially substituted for phenol to synthesize phenolic resin with different substitution rates under the action of an alkaline catalyst, and then to serve as the adhesive to produce bamboo scrimber. Bamboo bundles were impregnated with synthetic bio-oil phenolic resin to create bamboo scrimber, which was subsequently hot-pressed. The research shows that modified phenolic resins with a bio-oil substitution rate of under 30% have good physical and chemical properties, while the free aldehyde content of phenolic resin with 40% bio-oil substitution exceeds the limit value (0.3%) specified in the Chinese National Standard. The thermal stability of phenolic resins was also increased after bio-oil modification, indicated by the movement of the TG curve to higher temperature ranges. It was found that the bamboo scrimber prepared with 20% BPF resin adhesive had the best comprehensive properties of a good mechanical strength, hydrophobicity, and mildew resistance, particularly with an elastic modulus of 9269 MPa and a static bending strength of 143 MPa. The microscopic morphology showed that the BPF resin was well impregnated into the interior of the bamboo bundle and had a compact bonding structure within the bamboo scrimber. The anti-mold performance experiment found that the bio-oil-modified resin increased the anti-mold level of the bamboo scrimber from slightly corrosion-resistant to strong corrosion-resistant. The conclusions obtained from this study have a good reference value for achieving the comprehensive utilization of bamboo, helping to promote the use of all components, reduce the production cost of bamboo scrimber, and improve its mildew resistance performance. This provides new ideas for the development of low-cost mildew resistant bamboo scrimber novel materials.

Study on the dynamic changes of nutrient components and flavor compounds during the fermentation process of high-quality highland barley wine

The purpose of this study was to comprehensively understand the formation mechanism of nutrient components and flavor compounds during the fermentation process of high-quality highland barley wine (HHBW). The dynamic changes of physicochemical properties, non-volatile compounds and volatile flavor compounds in HHBW at different fermentation times were investigated. The results indicated that the nutrient components and physiologically active substances in HHBW, such as proteins, β-glucan, total phenols and total flavonoids were higher than those in commercial highland barley wine (HBW). In addition, the analysis results of HS-SPME-GC-MS revealed significant differences in flavor compounds at each fermentation stage, with alcohol being the main flavor compound. The contents of aldehydes and ketones decreased rapidly with the progress of fermentation. Lactic acid was the most important organic acid in HHBW. Correlation analysis revealed a negative association between citric acid and most alcohols and esters, while tartaric acid and succinic acid exhibited positive correlations with alcohols. Bitter amino acids, such as valine, isoleucine, leucine, arginine and lysine, were positively correlated with most of the ester flavor compounds. The study can provide a reference for a deep understanding of the mechanism of the formation of the characteristic flavor of HHBW.

Effects of hydrolyzed animal protein application on nitrogen translocation, phenolic and volatile profile of Ocimum basilicum L. under salinity conditions

The application of biostimulants based on hydrolysed animal protein to leaves (foliar) or nutrient solution was studied on hydroponically grown Genovese 'Marian' basil grown under salinity conditions. The effect on N yield and N fertilizer utilization was tested with the stable isotope 15N, which indicated the part of the plant that accumulated the highest amount of N. The use of the biostimulant in the nutrient solution produced the best results regarding N fertilizer utilization and N yield, being about 13 % higher than the foliar application and 24 % higher than the salt control (SC) treatment. In general, basil leaves contained the most N from the fertilizer. The total analysed phenolic content (TAPC) was 270.1 % higher in the nutrient solution-applied biostimulant (NSB) than in the control (C) treatment and 211.9 % higher than in the SC treatment. Foliar application of the biostimulant (FB) showed lower efficacy than NSB regarding phenolic contents. The most abundant individual phenolics in basil were dihydroxyphenyllactic acid dimer, caffeic acid hexoside derivatives, and rosmarinic acid. NSB increased the total sesquiterpene content by 25.2 % and the total alcohol content by 31.8 % compared to SC treatment. In addition, NSB increased the total aldehydes content by 27.0 % compared to SC treatment. The total volatile content was less variable than the individual volatiles. The results of our study show how different application methods of the biostimulant affect nitrogen conversion and utilization in different plant parts of basil and how they influence the internal quality of basil.

Composition analysis and health risk assessment of the hazardous compounds in cooking fumes emitted from heated soybean oils with different refining levels

The cooking fumes generated from thermal cooking oils contains various of hazardous components and shows deleterious health effects. The edible oil refining is designed to improve the oil quality and safety. While, there remains unknown about the connections between the characteristics and health risks of the cooking fumes and oils with different refining levels. In this study, the hazardous compounds, including aldehydes, ketones, polycyclic aromatic hydrocarbons (PAHs), and particulate matter (PM) in the fumes emitted from heated soybean oils with different refining levels were characterized, and their health risks were assessed. Results demonstrated that the concentration range of aldehydes and ketones (from 328.06 ± 24.64 to 796.52 ± 29.67 μg/m3), PAHs (from 4.39 ± 0.19 to 7.86 ± 0.51 μg/m3), and PM (from 0.36 ± 0.14 to 5.08 ± 0.15 mg/m3) varied among soybean oil with different refining levels, respectively. The neutralized oil showed the highest concentration of aldehydes and ketones, whereas the refined oil showed the lowest. The highest concentration levels of PAHs and PM were observed in fumes emitted from crude oil. A highly significant (p < 0.001) positive correlation between the acid value of cooking oil and the concentrations of PM was found, suggesting that removing free fatty acids is critical for mitigating PM concentration in cooking fumes. Additionally, the incremental lifetime cancer risk (ILCR) values of PAHs and aldehydes were 5.60 × 10−4 to 8.66 × 10−5 and 5.60 × 10−4 to 8.66 × 10−5, respectively, which were substantially higher than the acceptable levels (1.0 × 10−6) established by US EPA. The present study quantifies the impact of edible oil refining on hazardous compound emissions and provides a theoretical basis for controlling the health risks of cooking fumes via precise edible oil processing.

Electromediated Oxidation of Hydrolysed Bacterial Cellulose

The state-of-the-art method to isolate cellulose nanofibres employs a 2,2,6,6-Tetramethylpiperidinyloxyl (TEMPO)/NaBr/NaClO system, where the primary alcohols on the surface of cellulose microfibrils are oxidised. However, the large consumption of hypochlorite in this system makes it problematic for industrial implementation. Previously, electrochemical oxidation with a TEMPO catalyst has been reported for the preparation of cellulose nanofibres. Here, we present a study on the electromediated oxidation of bacterial cellulose (BC), the purest form of cellulose. BC has been used in a hydrolysed form, enabling the electromediated preparation of cellulose nanocrystals (CNCs), which is generally deemed even more costly than the preparation of cellulose nanofibres.In this work, the electromediated oxidation and cyclic voltammetry were performed in an electrochemical cell, which featured three electrodes: A Hg|Hg2SO4|K2SO4 reference electrode, a titanium net counter electrode, and a carbon foam working electrode, offering a high surface area. A static potential of 0.5 V was applied during the chronoamperometry and explored oxidation times were 3, 5, 9, 12 and 24 h.Using a TEMPO catalyst, the electromediated oxidation was applied to hydrolysed and non-hydrolysed BC fibres in a pH 10 buffer. The C6 primary hydroxyls of BC were successfully converted to sodium carboxylate groups. By the application of the TEMPO electro-mediated oxidation to hydrolysed BC for 9 h, high carboxylate and aldehyde concentrations of 1.4 and 0.3 mmol/g, respectively, were formed in the oxidized fibre. The carboxylate and aldehyde content was determined by a conductometric titration method. Surface morphologies after oxidation were investigated, showing alteration of the microfibril morphology for BC and the production of cellulose nanocrystals for hydrolysed BC. Hence, we present an effective and environmentally friendly route, which is particularly suitable for the preparation of cellulose nanocrystals.

Oxidative and nitrosative stress — the leading mechanisms of chronic pancreatitis and chronic obstructive pulmonary disease interaction and inducers of their progression

Background. The frequency of chronic pancreatitis (CP) comorbidity with chronic obstructive pulmonary disease (COPD) has significantly increased recently. It may be accompanied by changes in oxidant-antioxidant homeostasis and activates a cascade of reactions of mutual burdening of these pathologies. The purpose of the current research was to evaluate the intensity of lipid peroxidation, oxidative modification of proteins and the state of individual factors of the antioxidant defense system in the development and course of CP, depending on the comorbid COPD. Materials and methods. Three hundred and seventeen patients were examined, including 62 patients with CP alone (group 1), 132 CP patients with comorbid COPD (group 2), 123 patients with COPD alone (group 3). The content in blood of isolated double bonds in compounds, conjugated dienes, ketodienes and conjugated trienes, malonic aldehyde, nitrites/nitrates, reduced glutathione, the activity of catalase, glutathione-S-transferase, glutathione peroxidase were evaluated in all patients. Results. In CP patients with comorbid COPD, the maximum oxidative stress intensity among the compared groups was registered. There was a reliable increase in the content of malonic aldehyde — by 2.0 times (p &lt; 0.05), isolated double bonds — by 2.2 times (p &lt; 0.05), conjugated dienes — by 1.9 times (p &lt; 0.05), ketodienes and conjugated trienes — by 1.9 times (p &lt; 0.05), nitrites/nitrates — by 2.6 times (p &lt; 0.05). A reliable decrease in reduced glutathione content of erythrocytes was detec­ted: in group 1 — by 1.5 times, in group 2 — by 1.9 times (p &lt; 0.05), in group 3 — by 1.2 times (p &lt; 0.05). The compensatory increase in the activity of glutathione-S-transferase, glutathione peroxidase and blood catalase was revealed: in group 1 — by 1.3, 1.2 and 1.5 times (p &lt; 0.05); in group 2 — by 1.5, 1.3 and 1.8 times (p &lt; 0.05), in group 3 — by 1.2, 1.2 and 1.4 times, respectively (p &lt; 0.05). Conclusions. The comorbid course of CP and COPD is accompanied by the maximum intensity of oxidative and nitrosative stress compared to the isolated course of the disease. An increase was detected in intermediate and final metabolites of peroxide oxidation in the blood, oxidative modification of proteins, nitrites/nitrates in the blood against the background of a deep imbalance of antioxidant defense factors, an increase in ceruloplasmin content in the blood, which requires the administration of antioxidant agents to correct detected disorders and prevent the progression of both comorbid diseases.