RESUMEN
Nitrogen-containing organic compounds (NOCs) may potentially contribute to aqueous secondary organic aerosols, yet the different formation of NOCs in aerosol particles and cloud droplets remains unclear. With the in-situ measurements performed at a mountain site (1690 m a.s.l.) in southern China, we investigated the formation of NOCs in the cloud droplets and the cloud-free particles, based on their mixing state information of NOCs-containing particles by single particle mass spectrometry. The relative abundance of NOCs in the cloud-free particles was significantly higher than those in cloud residual (cloud RES) particles. NOCs were highly correlated with carbonyl compounds (including glyoxalate and methylglyoxal) in the cloud-free particles, however, limited correlation was observed for cloud RES particles. Analysis of their mixing state and temporal variations highlights that NOCs was mainly formed from the carbonyl compounds and ammonium in the cloud-free particles, rather than in the cloud RES particles. The results support that the formation of NOCs from carbonyl compounds is facilitated in concentrated solutions in wet aerosols, rather than cloud droplets. In addition, we have identified the transport of biomass burning particles that facilitate the formation of NOCs, and that the observed NOCs is most likely contributed to the light absorption. These findings have implications for the evaluation of NOCs formation and their contribution to light absorption.
Asunto(s)
Aerosoles , Contaminantes Atmosféricos , Monitoreo del Ambiente , Nitrógeno , Compuestos Orgánicos , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Contaminantes Atmosféricos/química , Nitrógeno/química , Nitrógeno/análisis , Compuestos Orgánicos/química , China , Atmósfera/química , Material Particulado/análisis , Material Particulado/químicaRESUMEN
This study demonstrated that NiO and Ni(OH)2 as Ni(II) catalysts exhibited significant activity for organic oxidation in the presence of various oxyanions, such as hypochlorous acid (HOCl), peroxymonosulfate (PMS), and peroxydisulfate (PDS), which markedly contrasted with Co-based counterparts exclusively activating PMS to yield sulfate radicals. The oxidizing capacity of the Ni catalyst/oxyanion varied depending on the oxyanion type. Ni catalyst/PMS (or HOCl) degraded a broad spectrum of organics, whereas PDS enabled selective phenol oxidation. This stemmed from the differential reactivity of two high-valent Ni intermediates, Ni(III) and Ni(IV). A high similarity with Ni(III)OOH in a substrate-specific reactivity indicated the role of Ni(III) as the primary oxidant of Ni-activated PDS. With the minor progress of redox reactions with radical probes and multiple spectroscopic evidence on moderate Ni(III) accumulation, the significant elimination of non-phenolic contaminants by NiOOH/PMS (or HOCl) suggested the involvement of Ni(IV) in the substrate-insensitive treatment capability of Ni catalyst/PMS (or HOCl). Since the electron-transfer oxidation of organics by high-valent Ni species involved Ni(II) regeneration, the loss of the treatment efficiency of Ni/oxyanion was marginal over multiple catalytic cycles.
Asunto(s)
Níquel , Oxidación-Reducción , Níquel/química , Catálisis , Aniones , Compuestos Orgánicos/química , Peróxidos/química , Ácido Hipocloroso/químicaRESUMEN
Cadmium (Cd2+) is a highly toxic heavy metal that can accumulate in the human body through contaminated food and water, posing great health risks. In this study, a label-free fluorescent aptasensor based on SYBR Green I (SGI) for the rapid and sensitive detection of Cd2+ in food samples was designed. The aptasensor utilizes a Cd2+-specific aptamer (Cd-(21)) and its complementary strand (CSCd-(21)) to form a double-stranded DNA (dsDNA) structure in the absence of Cd2+. SGI intercalates into the dsDNA, resulting in a strong fluorescence signal. In the presence of Cd2+, the aptamer undergoes a conformational change, preventing the formation of dsDNA and leading to a decrease in fluorescence intensity. Under optimized conditions, the aptasensor exhibited a linear response to Cd2+ concentrations ranging from 0.11 to 157.37 ng mL-1, with a limit of detection (LOD) of 0.07 ng mL-1. The aptasensor demonstrated high specificity and was successfully applied to detect Cd2+ in fruits and vegetables, with satisfactory recovery rates (95-111%). The proposed aptasensor provides a promising tool for the rapid and sensitive detection of Cd2+ in food.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Cadmio , Frutas , Límite de Detección , Verduras , Cadmio/química , Cadmio/análisis , Aptámeros de Nucleótidos/química , Verduras/química , Frutas/química , Técnicas Biosensibles/métodos , Fluorometría/métodos , Colorantes Fluorescentes/química , Contaminación de Alimentos/análisis , Benzotiazoles/química , Espectrometría de Fluorescencia/métodos , Quinolinas/química , Diaminas/química , Compuestos Orgánicos/químicaRESUMEN
The excessive presence of geogenic ammonium (NH4+) in groundwater poses a global environmental concern, commonly linked to the degradation of nitrogen-containing dissolved organic matter (DOM). However, there is a gap in systematic studies on the combination of soluble organic matter (SOM) in sediments and DOM in groundwater, with few indoor incubation experiments to validate their degradation pathways. This study utilized ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry to analyze the molecular characteristics of DOM and SOM in aquifer systems affected by geogenic NH4+. Subsequently, indoor incubation experiments spanning up to 140 d were conducted to verify the degradation pathways. The experimental results revealed a two-phase degradation process for both the DOM and SOM. The initial stage was characterized by the degradation of aliphatic compounds (ALC) with the production of polyphenols (PPE) and highly unsaturated compounds (HUC). The second stage was dominated by the degradation of PPE and HUC, accompanied by the re-consumption of some ALC, while more recalcitrant HUC persisted. Notably, the first stage of SOM degradation exceeded that of DOM degradation, indicating that SOM exhibited greater resistance to aging. This phenomenon may be attributed to a wider range of active enzymes in sediments, the rapid replenishment of SOM by organic matter in sediments, or the accelerated degradation of DOM. The experimental results aligned with the molecular characterization of DOM and SOM in actual aquifer systems. It is hypothesized that NH4+ produced through the direct mineralization of SOM may contribute more to the enrichment of NH4+ in groundwater than that produced through the mineralization of DOM. This study is the first to analyze DOM and SOM together in aquifer systems and validate their degradation pathways through incubation experiments, thereby providing novel insights into the enrichment of geogenic NH4+ in groundwater.
Asunto(s)
Compuestos de Amonio , Agua Subterránea , Contaminantes Químicos del Agua , Agua Subterránea/química , Contaminantes Químicos del Agua/química , Sedimentos Geológicos/química , Compuestos Orgánicos/química , SolubilidadRESUMEN
The chromogenic reaction between 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and ferrate [Fe(VI)] has long been utilized for Fe(VI) content measurement. However, the presence of electron-rich organic compounds has been found to significantly impact Fe(VI) detection using the ABTS method, leading to relative errors ranging from â¼88 to 100%. Reducing substances consumed ABTSâ¢+ and resulted in underestimated Fe(VI) levels. Moreover, the oxidation of electron-rich organics containing hydroxyl groups by Fe(VI) could generate a phenoxyl radical (Phâ¢), promoting the transformation of Fe(VI) â Fe(V) â Fe(IV). The in situ formation of Fe(IV) can then contribute to ABTS oxidation, altering the ABTSâ¢+:Fe(VI) stoichiometry from 1:1 to 2:1. To overcome these challenges, we introduced Mn(II) as an activator and 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic agent for Fe(VI) detection. This Mn(II)/TMB method enables rapid completion of the chromogenic reaction within 2 s, with a low detection limit of approximately 4 nM and a wide detection range (0.01-10 µM). Importantly, the Mn(II)/TMB method exhibits superior resistance to reductive interference and effectively eliminates the impact of phenoxyl-radical-mediated intermediate valence iron transfer processes associated with electron-rich organic compounds. Furthermore, this method is resilient to particle interference and demonstrates practical applicability in authentic waters.
Asunto(s)
Electrones , Oxidación-Reducción , Hierro/química , Compuestos Orgánicos/química , Benzotiazoles/química , Ácidos SulfónicosRESUMEN
The carbonyl functionality of natural organic matter (NOM) is poorly constrained. Here, we treated Suwannee River NOM (SRNOM) with ammonium acetate and sodium cyanoborohydride to convert ketone-containing compounds by reductive amination to their corresponding primary amines. The total dissolved nitrogen content increased by up to 275% after amination. Up to 30% of the molecular formulas of SRNOM contained isomers with ketone functionalities as detected by ultrahigh-resolution mass spectrometry. Most of these isomers contained one or two keto groups. At least 3.5% of the oxygen in SRNOM was bound in ketone moieties. The conversion of reacted compounds increased linearly with O/H values of molecular formulas and was predictable from the elemental composition. The mean conversion rate of reacted compounds nearly followed a log-normal distribution. This distribution and the predictability of the proportion of ketone-containing isomers solely based on the molecular formula indicated a stochastic distribution of ketones across SRNOM compounds. We obtained isotopically labeled amines by using 15N-labeled ammonium acetate, facilitating the identification of reaction products and enabling NMR spectroscopic analysis. 1H,15N HSQC NMR experiments of derivatized samples containing less than 20 µg of nitrogen confirmed the predominant formation of primary amines, as expected from the reaction pathway.
Asunto(s)
Cetonas , Cetonas/química , Compuestos Orgánicos/químicaRESUMEN
Algal proteins are an emerging source of functional foods. Herein, Chlorella pyrenoidosa protein (CPP)/xanthan gum-based hydrogels (HG) and beeswax-gelled oleogels (OG) are adopted to fabricate bigels. The phase inversion of bigels can be regulated by the ratio of OG and HG: As the OG increased, bigels turn from OG-in-HG (OG/HG) to a semicontinuous state and then HG-in-OG (HG/OG). In OG/HG bigels (OG ≤ 50 %), hydrophilic CPP acts as the emulsifier at the interface of OG and HG, while beeswax emulsifies the system in HG/OG bigels (OG = 80 %). A semicontinuous bigel appears during the transition between HG/OG and OG/HG. The increase of OG can enhance the viscoelasticity, hardness, adhesiveness, chewiness, and thermal stability. OG/HG bigels exhibit stronger thixotropic recovery and oil-holding capacity than HG/OG bigels. In the in-vitro digestion and food 3D printing, the high specific surface area and the highest thixotropic recovery caused by the emulsion structure of the OG/HG bigel (OG = 50 %) are conducive to the release of free fatty acids and molding of 3D-printed objects, respectively. This study provides a new approach to structure the gelled water-oil system with CPP and helps to develop edible algal proteins-based multiphase systems in food engineering or pharmacy.
Asunto(s)
Chlorella , Impresión Tridimensional , Ceras , Ceras/química , Chlorella/química , Hidrogeles/química , Digestión , Compuestos Orgánicos/química , Emulsiones/química , Proteínas Algáceas/química , Proteínas Algáceas/metabolismoRESUMEN
Terrestrial dissolved organic matter (DOM) plays critical roles in many biotic and abiotic environmental reactions as well as in water treatment. Its structure is therefore of great interest. We examined dissolved Suwannee River Humic Acid (HA) to probe the potential participation of exceptionally strong, negative charge-assisted hydrogen bonds, (-)CAHB, in DOM cohesion and interaction with small weak acids using high performance size exclusion chromatography (HPSEC), transmission electron microscopy, zeta-pH curves, and pH drift experiments. The results support a previously proposed two-tier state of aggregation, in which tightly-knit primary particles (≤ â¼10 kDa) form larger secondary aggregates (up to micrometer in size). Evidence for (-)CAHB is gained through zeta potential changes and pH drift experiments. The primary particles interact with (-)CAHB-capable solutes (simple carboxylic acids and phosphate) but not (-)CAHB-incapable solutes. We identified disruption of intra-segmental and inter-molecular (-)CAHB leading to swelling and disaggregation, as well as formation of nouveau (-)CAHB with free groups on HA. The effects were solute-concentration dependent and greater at pH 5 than pH 6, consistent with CAHB theory. Phosphate induced the greatest shifts in the HPSEC molecular size distribution curves. The shifts were unaffected by prior stripping of innate polyvalent metals. We conclude that the (-)CAHB contributes to the cohesion of DOM, affecting its size and charge, and provides a means by which weak acid pollutants, nutrients, and natural compounds can interact with DOM. Such interactions have implications for the behavior of DOM in the environment, the fate and transport of anthropogenic pollutants, and the roles DOM play in water treatment technologies.
Asunto(s)
Sustancias Húmicas , Enlace de Hidrógeno , Ríos , Ríos/química , Concentración de Iones de Hidrógeno , Cromatografía en Gel , Microscopía Electrónica de Transmisión , Compuestos Orgánicos/químicaRESUMEN
The substitution of margarine with candelilla wax (CW)-based oleogel is currently a prominent focus of research in the bakery industry. However, the use of CW-based oleogel in cookies increased starch digestibility, potentially posing a risk to human health. Thus, the anti-enzymatic mechanism of lipid-amylose complexes was used to evaluate the influence of olive diacylglycerol stearin (ODS) on starch digestibility in CW-based oleogel cookies. The in vitro digestibility analysis demonstrated that the DCW/ODS-35 cookie exhibited a increase of 27.72 % in slowly digestible starch (SDS) and resistant starch (RS) contents, compared to cookie formulated with margarine. The in-vivo glycemic index analysis revealed that the DCW/ODS-35 cookie had a medium glycemic index of 68. XRD pattern suggested that the presence of ODS in oleogels facilitated the formation of lipid-amylose complexes. The DSC analysis revealed that the addition of ODS resulted in the gelatinization enthalpy of DCW-based cookies increased from 389.9 to 3314.9 J/g. The FTIR spectra indicated that the combination of ODS could promote a short-range ordered structure in DCW-based cookies. Overall, these findings demonstrated that the utilization of DCW-based oleogel presented a viable alternative to commercial margarine in the development of CW-based cookies with reduced starch digestibility.
Asunto(s)
Amilosa , Compuestos Orgánicos , Ceras , Ceras/química , Amilosa/química , Amilosa/análisis , Compuestos Orgánicos/química , Almidón/química , Lípidos/química , Digestión , Almidón ResistenteRESUMEN
In recent years, oleogel as a viscoelastic semi-solid to replace trans fatty acids and reduce saturated fatty acids in food has received more and more attention. Herein, an emulsion template method was used to produce soybean oil-based oleogels with seven different ester emulsifiers and soy protein isolate as oleogelators. The chemical and physical characteristics of oleogels produced via various crosslinking factors were comparatively examined. Results revealed that all oleogels generated ß-type needle crystals and exhibited high oil-holding capacity (>80 %), among which glycerol monolaurate G2 and diacetyl tartaric acid ester of mono-diglycerides G6 exhibited the strongest oil-holding capacity (96.6 % and 96.2 %, respectively). Furthermore, all oleogels exhibited strong thixotropic recovery, high thermal stability, as well as high gel strength (G' > G''). Of these, G2 and G6 exhibited the highest thixotropic recovery rates at 74.54 % and 78.19 %, respectively. Additionally, in accelerated oxidation trials, the peroxide value and thiobarbituric acid reactive substances of all oleogels had low oxidation rates, indicating high oxidative stability. These results contribute to a better understanding of oleogels for formulating trans-free and low-saturated foodstuffs with desired physical and functional properties.
Asunto(s)
Emulsionantes , Compuestos Orgánicos , Proteínas de Soja , Compuestos Orgánicos/química , Proteínas de Soja/química , Emulsionantes/química , Aceite de Soja/química , Oxidación-Reducción , Ésteres/química , Emulsiones/químicaRESUMEN
The use of ultrafiltration to isolate high molecular weight dissolved organic matter (HMWDOM) from seawater is a fundamental tool in the environmental organic chemist's toolbox. Yet, important characteristics of HMWDOM relevant to its origin and cycling, such as its molecular weight distribution, remain poorly defined. We used diffusion-ordered NMR spectroscopy coupled with mixed-mode chromatography to separate and characterize two major components of marine HMWDOM: acylpolysaccharides (APS) and high molecular weight humic substances (HS). The molecular weights (MWs) of APS and HS both fell within distinct, narrow envelopes; 2.0-16 kDa for APS and 0.9-6.5 kDa for HS. In water samples from the North Pacific Ocean the average MW of both components decreased with depth through the mesopelagic. However, the minimum MW of APS was >2 kDa, well above the molecular weight cutoff of the ultrafilter, suggesting APS removal processes below 2 kDa are highly efficient. The MW distribution of APS shows only small variations with depth, while the MW distribution of HS narrowed due to removal of HMW components. Despite the narrowing of the MW distribution, the concentration of HS did not decrease with depth between 15 and 915 m. This suggests that HMW HS produced in surface waters was either degraded into lower MW compounds without significant remineralization, or that HMW HS was remineralized but replaced by an additional source of HS in the mesopelagic ocean. Based on these results, we propose potential pathways for the production and removal of these major components of HMWDOM.
Asunto(s)
Sustancias Húmicas , Peso Molecular , Agua de Mar/química , Espectroscopía de Resonancia Magnética , Compuestos Orgánicos/químicaRESUMEN
This research addresses the presence of substances of very high concern (SVHCs) confronting the drinking water sector. Responding adequately to the potential hazards by SVHCs, knowledge of emission pathways, toxicity, presence in drinking water sources, and removability during water production is crucial. As this information cannot be received for each compound individually, we employed a detailed clustering approach based on chemical properties and structures of SVHCs from lists with over 1,000 compounds. Through this process, 915 substances were divided into 51 clusters. We tested this clustering in risk assessment. To assess the risks, we developed toxicity prediction models utilizing random forests and multiple linear regression. These models were applied to make toxicity predictions for the list of compounds. This study shows that clustering is a viable approach to reducing sample size. In addition, the toxicity models provide insights into the potential human health risks. This research contributes to more informed decision-making and improved risk assessment in the drinking water sector, aiding in the protection of human health and the environment. This principle is generally applicable. If in a group a suitable representative is found, data from experiments with this compound can be used to gauge the behaviour of chemicals in this group.
Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , Medición de Riesgo/métodos , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Análisis por Conglomerados , Agua Potable/química , Agua Potable/análisis , Humanos , Compuestos Orgánicos/química , Tamaño de la MuestraRESUMEN
The natural dual nanofibril system consisting of the rigid semicrystalline nanofibrils disintegrated from citrus fiber (CF) and soft semiflexible nanofibrils self-assembled from glycyrrhizic acid (GA) has been recently shown to be effective structural building blocks for fabrication of emulsion gels. In this work, the effect of the CF nanofibrils prepared by different mechanical disintegration approaches (i.e., high-pressure microfluidization and hydrodynamic cavitation) on the interfibrillar CF-GA interactions and the subsequent formation and properties of emulsion gels were investigated, with the aim of evaluating the potential of the dual nanofibril-stabilized emulsion gels as templates for synthesizing all-natural edible oleogels. The obtained results demonstrate that compared to the cavitation, the high-pressure microfluidization is more capable of generating CF nanofibrils with a higher degree of nanofibrillation and individualization, thus forming a denser CF-GA gel network with higher viscoelasticity and structural stability due to the stronger multiple intrafibrillar and interfibrillar interactions. The emulsion gels stabilized by the dual nanofibril system are demonstrated to be an efficient template to fabricate solid-like oleogels, and the structural properties of the oleogels can be well tuned by the mechanical disintegration of CF and the GA nanofibril concentration. The prepared oleogels possess high oil loading capacity, dense network microstructure, superior rheological and large deformation compression performances, and satisfactory thermal stability, which is attributed to the compact and ordered CF-GA dual nanofibrillar network via multiple hydrogen-bonding interactions in the continuous phase as well as at the droplet surface. This study highlights the unique use of all-natural dual nanofibrils to develop oil structured soft materials for sustainable applications.
Asunto(s)
Citrus , Emulsiones , Geles , Ácido Glicirrínico , Nanofibras , Compuestos Orgánicos , Emulsiones/química , Ácido Glicirrínico/química , Citrus/química , Nanofibras/química , Compuestos Orgánicos/química , Geles/química , Reología , ViscosidadRESUMEN
The depth-dependent dynamics of dissolved organic matter (DOM) structure and humification in an artificial lake limits the understanding of lake eutrophication and carbon cycling. Using fluorescence regional integration (FRI) and parallel factor analysis (PARAFAC) models to analyze the 3D fluorescence spectroscopy dataset, we revealed the depth-dependent structure and vertical distribution of DOM in the estuarine and center regions of Lake Hongfeng. The percentage fluorescence response (Pi,n) showed humic acid is an important part of DOM in Lake Hongfeng. Fluorescence results show that the fulvic-like and protein-like materials in HF1-DOM located at the estuarine position showed greater variation in the middle stage, probably due to human influence and sediment suspension. Fluorescence index (PI+II+IV,n/PIII+V,n and FIC4/FIC3) can be used to indicate the degree of humification of DOM in artificial lakes. Results of each index show that the estuary is more affected by human activities, and the humification degree is significantly lower than that of the center of the lake. The evaluation index system of the humification degree of artificial lake established in this study can effectively predict the eutrophication state of the typical area of artificial lake and deeply understand the possible important influence of human activities on the carbon cycle of lake.
Asunto(s)
Sustancias Húmicas , Lagos , Lagos/química , Sustancias Húmicas/análisis , Espectrometría de Fluorescencia , Compuestos Orgánicos/análisis , Compuestos Orgánicos/química , Monitoreo del Ambiente/métodos , EutrofizaciónRESUMEN
Three new types of composite oleogel formulations were designed. Specifically, oleogels were prepared using 90% grapeseed oil as the oil phase and carnauba wax (CW)/beeswax/rice bran wax-bovine bone protein (BBP) as gelators. All samples were solid and had an oil-binding capacity of >90%. BBP addition considerably improved the waxy texture of the oleogel and had an important effect on the crystalline network. X-ray diffractometry indicated that BBP increased the ß'-crystal content. All samples showed sol-gel thermodynamic behavior under temperature scanning. Fourier-transform infrared spectroscopy and molecular docking confirmed the formation of noncovalent interactions dominated by van der Waals forces during the development of the oleogel. The optimal components of the three oleogels exhibited an excellent effect of slowing down the release of free fatty acids. This study could serve as a reference for the development and application of wax-protein as a new binary gelator in the food industry.
Asunto(s)
Simulación del Acoplamiento Molecular , Compuestos Orgánicos , Ceras , Animales , Bovinos , Ceras/química , Compuestos Orgánicos/química , Aceites de Plantas/química , Huesos/químicaRESUMEN
To improve nutritional health, a low-salt (0.5 %) silver carp (Hypophthalmichthys molitrix) surimi gel with α-tocopherol, soybean oil, and glyceryl monostearate oleogel was fabricated and evaluated for textural qualities, lipid oxidation, and in-vitro digestion analysis. Based on the texture profile analysis, gel strength, water holding capacity (WHC), rheological, protein secondary structure, and microstructural examination, 5 % oleogel addition to low-salt surimi exhibited similar physicochemical properties to regular-salt surimi gels. By crosslinking myosin and filling protein network voids, the oleogel increased surimi gel density. Increasing oleogel content improved the physicochemical qualities of heat-induced surimi, causing protein aggregation during digestion and reducing digestibility. The presence of oleogel altered protein secondary structure, reducing α-helix content and increasing ß-sheet and other structures, enhancing WHC and gel strength of low salt surimi. Adding oleogel improved the antioxidant activity of digestive solutions. This study will help understand myosin-oleogel interaction and the development of sustainable and nutritious surimi-based foods.
Asunto(s)
Carpas , Digestión , Productos Pesqueros , Geles , Aceite de Soja , alfa-Tocoferol , Animales , alfa-Tocoferol/química , Aceite de Soja/química , Productos Pesqueros/análisis , Geles/química , Compuestos Orgánicos/química , Monoglicéridos/química , Monoglicéridos/farmacología , Proteínas de Peces/química , Reología , GlicéridosRESUMEN
The effectiveness of ozonation, one of the techniques known for destroying organic contaminants from wastewater, depends on the composition of the wastewater matrix. The required ozone (O3) dose is determined based on the target compounds during ozonation. Hydroxyl radicals are quantified using a probe compound. The para-chlorobenzoic acid (pCBA) is typically used as a probe compound to measure hydroxyl radicals. However, real-time measurement is impossible, as the analysis process consumes time and resources. This study aimed to evaluate the spectroscopic characteristics of various organic substances in wastewater ozonation through fluorescence excitation-emission matrix and parallel factor analysis. The study also demonstrated that real-time analyzable tryptophan-like fluorescence (TLF) can be used as a hydroxyl radical index. Importantly, the correlation between para-chlorobenzoic acid and TLF was derived, and the results showed a high correlation (R2 = 0.91), confirming the reliability of our findings. Seven trace organic compounds, classified based on their reactivity with O3 and hydroxyl radicals, were selected as target compounds and treated with O3. The TLF index was used as a model factor for the removal rate of the target compounds. The experimental and model values matched when the O3 dose was below 1.0 g O3/g DOC (RMSE: 0.0445-0.0895).
Asunto(s)
Radical Hidroxilo , Ozono , Triptófano , Aguas Residuales , Contaminantes Químicos del Agua , Ozono/química , Ozono/análisis , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Triptófano/análisis , Triptófano/química , Radical Hidroxilo/química , Radical Hidroxilo/análisis , Fluorescencia , Eliminación de Residuos Líquidos/métodos , Compuestos Orgánicos/análisis , Compuestos Orgánicos/química , Clorobenzoatos/química , Clorobenzoatos/análisis , Espectrometría de Fluorescencia/métodos , Purificación del Agua/métodosRESUMEN
GC-MS/MS combines the superior chromatographic resolution of GC with the specific and sensitive detection of tandem MS. On paper, it is an ideal system for the routine analyses of organic acids, yet very few studies have used and published such methods. This is likely due to several challenges highlighted in this communication. Briefly, the combination of EI ionization with MRM detection provides arguably insufficient specificity when targeting organic acids. Moreover, the narrow peaks generally produced by GC can lead to inaccurate quantification when the mass spectrometer's cycle time is too long. Potential solutions to these problems are discussed.
Asunto(s)
Cromatografía de Gases y Espectrometría de Masas , Espectrometría de Masas en Tándem , Cromatografía de Gases y Espectrometría de Masas/métodos , Espectrometría de Masas en Tándem/métodos , Compuestos Orgánicos/análisis , Compuestos Orgánicos/química , Ácidos/análisis , Ácidos/químicaRESUMEN
Oleogels containing bioactive substances such as citral (CT) are used as functional food ingredients. However, little information is available on the influence of different oleogel network structure caused by CT addition and fatty acid distribution on its digestion behavior. Coconut oil, palm oil, high oleic peanut oil, safflower seed oil, and perilla seed oil were used in this study. The results showed that perilla seed oil-CT-based oleogels had the highest oil-holding capacity (99.03 ± 0.3), whereas CT addition higher than 10 wt% could lead to the morphology collapse of oleogels. Physical and thermodynamic analyses revealed that CT could reduce oleogel hardness and higher unsaturated fatty acid content is more likely to form oleogel with stable and tight crystalline network. Moreover, the dense structure of oleogels hinders the contact between oleogels and lipase, thus weakening triglyceride digestion. These findings provide valuable insights into the design of oleogels loading with CT.
Asunto(s)
Monoterpenos Acíclicos , Digestión , Ácidos Grasos , Compuestos Orgánicos , Aceites de Plantas , Monoterpenos Acíclicos/química , Aceites de Plantas/química , Ácidos Grasos/química , Ácidos Grasos/metabolismo , Compuestos Orgánicos/química , Monoterpenos/química , Modelos Biológicos , Humanos , Aceite de Palma/química , Aceite de Coco/química , Ácido alfa-LinolénicoRESUMEN
The ideal physicochemical properties of bigels are important for food applications. Therefore, a new bigel was prepared based on mixed beef tallow and soybean oil oleogel and deacetylated konjac glucomannan (KGM) hydrogel. The effect of the deacetylation degree of KGM on the physicochemical properties and microstructure of bigels was studied. The bigel containing moderate deacetylation degree of KGM had better rheological properties and hardness (319.84 g) than that with low and high deacetylation degrees of KGM. The interactions among the bigel components were analyzed by Fourier transform infrared spectroscopy and molecular dynamics simulation, indicating that the formation of the bigels was dominated by electrostatic interactions. Overall, the bigels containing moderate deacetylation degree of KGM had better physical properties, which may provide a theoretical foundation to develop bigels with low cholesterol, trans and saturated fats levels to replace traditional solid fats in food industry.