Pipette-tip kapok fiber-based solid-phase extraction/in-situ derivatization for the rapid and green analysis of furfural compounds.

Furfural compounds, including 5-hydroxymethylfurfural, furfural, and 5-methylfurfural, are common in foods and pose health risks. This study presents a pipette-tip solid-phase extraction with in-situ derivatization (PT-KF-SPE/ISD) method for rapid analysis of furfural compounds in various food matrices. Utilizing natural kapok fiber as an efficient adsorbent, this method integrates extraction and derivatization into a single step via a simple pull-push operation. Derivatization with 2,4-dinitrophenylhydrazine increases the hydrophobicity and ultraviolet absorption of furfural compounds, enabling sensitive liquid chromatography-ultraviolet detection. The method shows good linearity, sensitivity, and reproducibility, with limits of detection in ranges of 3.9-6.0 ng/mL. Real sample analysis confirms its applicability in detecting furfural compounds in beverages and herbal products, offering a reliable and eco-friendly solution for food safety and quality control. Five greenness assessment metrics demonstrate the method's excellent environmental friendliness. This approach highlights the advantages of combining natural adsorbents with in-situ derivatization for efficient food analysis.

[Oscillation-static cycle cultivation enhances the synthesis of triterpenes and mycelium activity in Ganoderma lucidum].

Ganoderma lucidum is a precious fungus with both edible and medicinal values and has a long history of medical use. Triterpenes as the main active components endow G. lucidum with anti-tumor, antioxidant, and other pharmacological activities. The present study endeavors to establish a proficient liquid-state fermentation technology for the enhanced production of triterpenes. In view of the limitations inherent in conventional submerged fermentation and oscillation-static two-stage cultivation, this study established an oscillation-static cycle cultivation process and optimized the cultivation conditions by building an artificial neural network model based on genetic algorithms. The cultivation conditions for the high-yield production of triterpenes were optimized as follows: 2.8 days of oscillation, 7.3 days of static cultivation, 0.2 day of oscillation, and 0.3 day of static cultivation. Under these conditions, the content of triterpenes reached 20.82 mg/g. The yield of triterpenes reached 129.09 mg/L, showing a remarkable increase of 324.78% compared with that of the Z10J0 method. Moreover, the established method shortened the cultivation cycle by 10.6 days. The mycelia cultivated under this regimen exhibited commendable anti-tumor and antioxidant activities. This study not only presents an economical liquid-state fermentation approach but also streamlines the fermentation flow, reduces fermentation duration, and effectively ameliorates drawbacks associated with conventional cultivation methods. In addition, this study gives valuable insights into the scaled application of liquid-state fermentation in the high-yield production of triterpenes, which showcases broad prospects.

Convenient analysis of sartan adulteration in herbal oral liquids using cotton fiber-supported liquid extraction and with high-performance liquid chromatography-fluorescence detection.

This research introduces a novel approach for detecting sartan antihypertensive drug adulteration in herbal oral liquids using cotton fiber-supported liquid extraction (CF-SLE) combined with high-performance liquid chromatography-fluorescence detection (HPLC-FLD). Optimal extraction parameters were determined through systematic method development, establishing a sample solution with a pH of 3.0, using 200 mg of cotton fiber, ethyl acetate as the extraction solvent, and a solvent volume of 4 mL. These conditions demonstrated robust extraction efficiency and were further validated for precision and accuracy, with intra- and inter-day relative standard deviations consistently below 7.5 % and relative recoveries ranging from 88.5 % to 106.1 %. The method exhibited excellent linearity for sartans, with R² values greater than 0.993 across a concentration range of 10-2000 ng/mL. Detection limits were effectively established in the range of 2.6-3.1 ng/mL, indicating that the method's sensitivity is adequate for the intended screening purposes. This validated method was then applied to real sample analysis, confirming its potential for routine use in detecting illegal additives within complex herbal matrices, thereby ensuring consumer safety and supporting regulatory compliance.

Compact silicon-based Ka-band tunable-phase photonic microwave frequency downconverter.

In this paper, a compact silicon-based photonic microwave frequency downconverter with broadband operation capability and continuous phase shift tunability is proposed and experimentally demonstrated. The photonic converter mainly comprises two micro-ring modulators (MRMs) connected in parallel and a cascaded resonator-based optical bandpass filter (OBPF) whose size is merely 200 × 700 µm2. In the proposed device, a radio frequency (RF) signal and a local oscillator (LO) signal drive the two MRMs for realizing the electro-optic conversion. The OBPF is utilized for selecting the first-order sidebands of both RF and LO signals. By manipulating the phase difference between the RF and LO optical sidebands through thermal-optic effect, the phase of the obtained intermediate frequency (IF) signal from a photodiode can be tuned continuously. Experimental results demonstrate a 137° phase shift while the RF signals of 20 and 40 GHz are downconverted to an IF signal of 0.4 GHz, which indicates the photonic microwave downconverter can be used in the Ka-band phased-array receiver.

Effect of temperature on structural configuration and immunoreactivity of pH-stressed soybean (Glycine max) agglutinin.

Soybean agglutinin (SBA) was purified using ammonium sulfate precipitation and liquid chromatography. Purified SBA was used to produce monoclonal antibodies through hybridoma technology. SBA secondary structure was studied using circular dichroism. pH-stressed (pHs 3.0, 7.2, 8.5, and 9.6) SBA physical properties (particle size, ζ-potential, and aggregation temperature) were investigated. Gel electrophoresis (non-native and native) was used to study heat-induced structural configuration changes in SBA. The effect of pH and temperature on the immunoreactivity of SBA was analyzed using enzyme-linked immunosorbent assay and immunoblots probed with two anti-SBA monoclonal antibodies with either linear or conformational epitopes. The hemagglutinating activity of heated SBA was measured by hemagglutination assay. Our results indicated that SBA had the least thermostability at pH 3.0 and the highest at pH 8.5. Temperature-induced structural configuration change on pH-stressed SBA led to immunoreactivity change. Heat-induced (70 and 80 °C) soluble SBA aggregation was proportionally related to hemagglutinating activity reduction.

Manganese oxide-loaded activated carbon for ammonium removal from wastewater: the roles of adsorption and oxidation.

The urgent need to address the severe issue of nitrogen pollution has prompted the search for a functional and easy recycling material. In this study, manganese oxides (MnOx) were loaded on activated carbon (AC), resulting in a composite known as AC-MnOx, for efficient ammonium removal from aqueous solutions. The results indicated a remarkable 15.6-fold increase in ammonium removal efficiency and a fivefold enhancement in removal capacity for AC-MnOx (3.20 mg/g) compared to AC. Under specific conditions (initial NH4+-N concentration of 15 mg/L, adsorbent dose of 2.5 g, pH of 6.5, and temperature of 35 ℃), the highest achieved ammonium removal efficiency reached 94.6%. Furthermore, the study distinguishes the contributions of catalytic oxidation and adsorption in the removal process. The adsorption process was effectively modeled using pseudo-second-order kinetics and Langmuir isotherm models. Interestingly, the amount of oxidation conversion (Ntur) exhibited a linear relationship with the dosage when the initial ammonium concentration was sufficiently high, while the relationship between initial ammonium concentration and the ratio of Ntur to adsorption capacity (Nsur) followed a negative exponential trend. The removal mechanisms involved electrostatic interaction between ammonium and the negatively charged dehydrogenated hydroxyl groups (- OHsur) or cation tunnel in crystal structures of MnOx, ion exchange adsorption, and the oxidation impact of MnOx. This research provides valuable insights into the application of immobilized MnOx media for ammonium removal. Moreover, filling AC-MnOx into constructed wetlands (CW) proved to be an effective method for reducing ammonium pollution, demonstrating its potential in the field of engineering wastewater treatment.

Immunodetection of finfish residues on food contact surfaces.

Finfish is one of the major allergenic foods, whose declaration is required on packages. Undeclared allergenic residues are mainly derived from allergen cross-contact. Swabbing of food contact surfaces helps to detect allergen cross-contamination. This study aimed to establish a competitive enzyme-linked immunosorbent assay (cELISA) to quantify the major finfish allergen, parvalbumin, from swab samples. First, parvalbumin from four finfish species was purified. Its conformation was investigated under reducing, non-reducing and native conditions. Second, one anti-finfish parvalbumin monoclonal antibody (mAb) was characterized. This mAb had a calcium-dependent epitope which was highly conserved in finfish species. Third, one cELISA was established with a working range between 0.59 ppm and 150 ppm. It showed a good recovery of swab samples on food-grade stainless steel and plastic surfaces. Overall, this cELISA could detect a trace amount of finfish parvalbumins on cross-contact surfaces, which is suitable for allergen surveillance in the food industry.

Composition, structural configuration, and antigenicity of Atlantic cod (Gadus morhua) tropomyosin.

Tropomyosin, a myofibrillar muscle protein, has been recognized as a finfish allergen. In this study, tropomyosin from Atlantic cod fillets (Gadus morhua, CTM) was purified using a two-step purification strategy (isoelectric precipitation and anion-exchange chromatography). CTM structural configuration in two sample matrices (impure and pure) were elaborated using different polyacrylamide gel electrophoresis (native, non-reducing, and reducing PAGE). Their corresponding immunoblots were conducted to investigate CTM antigenicity under three conditions. Overall, CTM retained solubility, integrity, and antigenicity after heat treatment. Three CTM monomeric α-type isoforms (33 kDa) were identified using two-dimensional PAGE. Under native condition, the vast majority of CTM existed in the disulfide-reduced dimeric form (66 kDa). Under non-reducing condition, sodium dodecyl sulfate (anionic surfactant) broke CTM dimers, leaving monomers and disulfide-induced tetramers. Under reducing condition, ß-mercaptoethanol (thiol reducing agent) dissociated disulfide-linked CTM tetramers (132 kDa) into monomers (33 kDa). CTM retained antigenicity regardless of structural configuration under different conditions.

Online analysis of chemical composition and size distribution of fresh cigarette smoke emitted from a heated tobacco product.

Online analysis of chemical composition of cigarette smoke of a heated tobacco product (HTP) was performed by using a home-made vacuum ultraviolet (VUV) lamp-based photoionization time-of-flight (TOF) mass spectrometer. A capillary inlet and an aerodynamic lens were utilized to sample the gas- and particulate-phase of the HTP smoke, without dilution and pretreatment, which can be switched from each other within minutes. A thermal desorption unit was installed to vaporize the particulate-phase into gas and its vaporization temperature was determined, based on an equilibrium between the evaporation efficiency and the thermal decomposition of organic compounds. Then these species were softly ionized by VUV photons and their ions were measured by a reflectron TOF mass analyzer. Meanwhile, the puff-by-puff resolved size distributions of the HTP smoke were probed with a commercial scanning mobility particle sizers (SMPS). The mean diameters of particles firstly increase with the puff number, mainly located in the range of 200 - 300 nm, and then approached a steady state. This method was validated to measure the physical-chemical characteristics of the HTP cigarette smoke.•A capillary inlet and an aerodynamic lens were utilized to sample the gas- and particulate-phase of the HTP smoke.•Chemical composition of the HTP smoke was measured by using a compact VUV photoionization mass spectrometer.•The particle size distribution of the HTP smoke without dilution was measured online.

Isolation and Characterization of Chicken Serum Albumin (Hen Egg Alpha-Livetin, Gal d 5).

Chicken serum albumin, i.e., hen egg alpha-livetin, is a recognized food allergen in chicken meat and hen eggs. Currently, there is no immunoassay available for its detection from food matrices. The characterization of chicken serum albumin-specific antibodies and the extraction of the target protein are essential for immunoassay development. One monoclonal antibody (mAb), 3H4, was used in this study due to its selectivity to a linear epitope on avian serum albumin. To study the extraction of chicken serum albumin, phosphate-buffered saline (PBS) with two additives, i.e., sodium dodecyl sulfate (SDS) and dithiothreitol (DTT), was used for its extraction from chicken blood plasma and hen egg yolk. SDS and DTT improved the chicken serum albumin's recovery and enhanced chicken serum albumin's immunodetection. In addition, chicken serum albumin retained the best solubility and immunoreactivity after heat treatment in a neutral condition. It experienced degradation and aggregation in acidic and alkaline conditions, respectively. Overall, PBS containing 0.1% SDS and 1 mM DTT (pH 7.2) was a better extraction buffer for chicken serum albumin. However, the complexity of the food matrix and elevated temperature could reduce its solubility and immunoreactivity.

Aquatic food animals in the United States: Status quo and challenges.

This review summarizes (1) the U.S. status quo for aquatic food animal production and marketing; (2) major food safety and quality issues/concerns for aquatic food animals in the United States, including fish misbranding, finfish/shellfish allergies, pathogens, toxins and harmful residues, microplastics, and genetically engineered salmon; and (3) various U.S. regulations, guidances, and detection methods for the surveillance of fishery products. Overall, fish misbranding is the biggest challenge in the United States due to the relatively low inspection rate. In addition, due to the regulatory differences among countries, illegal animal drugs and/or pesticide residues might also be identified in imported aquatic food animals. Future regulatory and research directions could focus on further strengthening international cooperation, enhancing aquatic food animal inspection, and developing reliable, sensitive, and highly efficient detection methods.

Non-Specific Binding and Cross-Reaction of ELISA: A Case Study of Porcine Hemoglobin Detection.

Different types of enzyme-linked immunosorbent assays (ELISA) have been widely used to control food safety and quality. To develop an accurate and reproducible ELISA, false immunodetection results caused by non-specific binding (NSB) and cross-reaction must be prevented. During the case study of sandwich ELISA development for the detection of porcine hemoglobin (PHb), several critical factors leading to NSB and cross-reaction were found. First, to reduce the NSB of the target analyte, the selection of microplate and blocker was discussed. Second, cross-reactions between enzyme-labeled secondary antibodies and sample proteins were demonstrated. In addition, the function of (3-aminopropyl)triethoxysilane (APTES) was evaluated. Overall, this study highlights the essence of both antibody and assay validation to minimize any false-positive/negative immunodetection results.

A simultaneous extraction/derivatization strategy coupled with liquid chromatography-tandem mass spectrometry for the determination of free catecholamines in biological fluids.

The current study presents a convenient, rapid and effective simultaneous extraction/derivatization (SEDP) strategy for effective pretreatment of catecholamines (CAs). Commercial zirconium oxide (ZrO2) nanoparticles were employed for the selective capturing of cis-diol containing CAs to remove the biological interferences and phenyl isothiocyanate (PITC) was used for derivatization to improve the ionization and to improve the chromatographic separation. The extraction and derivatization procedures were integrated into one step to simplify the sample pretreatment. Excessive derivatization reagents were removed as well, reducing the degree of contaminations in mass spectrometry. The factors affecting the SEDP process were optimized and the results showed that the detection sensitivity and chromatographic separation of CAs greatly improved compared with underivatized CAs, during LC-MS/MS analysis. Combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), quantifying the concentration of norepinephrine (NE), epinephrine (E) and dopamine (DA) in biological fluids was validated in ranges of 1-200.0 ng/mL with a satisfactory correlation coefficient (R2 > 0.997). The obtained recoveries were in the range of 91.0-109.5% with RSDs less than 9.4%. Finally, significant changes in CAs levels in urine samples of healthy people and pheochromocytoma patients were detected. The developed method offers comparative advantages in terms of sensitivity, specificity and selectivity.

Effect of Processing on Fish Protein Antigenicity and Allergenicity.

Fish allergy is a life-long food allergy whose prevalence is affected by many demographic factors. Currently, there is no cure for fish allergy, which can only be managed by strict avoidance of fish in the diet. According to the WHO/IUIS Allergen Nomenclature Sub-Committee, 12 fish proteins are recognized as allergens. Different processing (thermal and non-thermal) techniques are applied to fish and fishery products to reduce microorganisms, extend shelf life, and alter organoleptic/nutritional properties. In this concise review, the development of a consistent terminology for studying food protein immunogenicity, antigenicity, and allergenicity is proposed. It also summarizes that food processing may lead to a decrease, no change, or even increase in fish antigenicity and allergenicity due to the change of protein solubility, protein denaturation, and the modification of linear or conformational epitopes. Recent studies investigated the effect of processing on fish antigenicity/allergenicity and were mainly conducted on commonly consumed fish species and major fish allergens using in vitro methods. Future research areas such as novel fish species/allergens and ex vivo/in vivo evaluation methods would convey a comprehensive view of the relationship between processing and fish allergy.

In vitro toxicological evaluation of a tobacco heating product THP COO and 3R4F research reference cigarette on human lung cancer cells.

Cigarette smoking increases health risks, such as respiratory diseases and heart diseases. Despite the decline in smoking rates in some countries, millions of adults still choose to smoke cigarettes. The use of next-generation nicotine delivery devices, such as tobacco heating products (THPs), may become a potentially safer alternative to smoking. Here, we report on the development of an electrically heated THP, coded as THP COO, with three different flavored tobacco sticks. The purpose of the study was to measure the levels of a list of harmful and potentially harmful constituents (HPHCs) in the total particulate matter (TPM) generated and to conduct a set of toxicological assessments of THP COO as compared with 3R4F reference cigarette. For all 55 HPHCs identified, the levels generated by the THP tobacco sticks were significantly lower in comparison to those in 3R4F TPM. The rate of reduction of HPHCs was between 68.6% and 99.9% under Health Canada Intense (HCI) smoking regimen. Human lung cancer cells (NCI-H292) exposed to 3R4F TPM showed dose-dependent responses for most of the 15 in vitro toxicity endpoints, whereas those exposed to comparable doses of THP COO TPMs did not. Therefore, exclusive use of the THP COO products may reduce the exposure of those tested HPHCs and thus potentially reduce health risk of smoking.

Face masks matter: Eurasian tree sparrows show reduced fear responses to people wearing face masks during the COVID-19 pandemic.

Continuous exposure to human activity has led to considerable behavioural changes in some wildlife populations. Animals are more likely to survive in a changing environment by adjusting their behaviour to repeatedly occurring but harmless stimulations. During the COVID-19 pandemic, starting in late 2019, face masks were recommended to the public to prevent the spread of pathogens. In this context, we compared the flight initiation distance (FID) of the Eurasian tree sparrow (Passer montanus), a commonly seen bird across China, in Yibin and Dazhou, Sichuan, in response to people with or without face masks. After continuous exposure to people wearing face masks for nearly six months, sparrows evidently became adapted to people wearing face masks, and correspondingly showed shorter FIDs in response to people wearing masks. To our knowledge, this is the first study showing that birds show reduced fear responses to people wearing face masks during the COVID-19 pandemic. Our results suggest a novel aspect of short-term adaptation of wildlife to human behaviour, and that the learning ability of sparrows allows them to adjust their behaviours to adapt to such subtle changes in the environment.

Monoclonal antibody-based sandwich enzyme-linked immunosorbent assay for porcine hemoglobin quantification.

The major objective of this study was to establish a monoclonal antibody (mAb)-based sandwich enzyme-linked immunosorbent assay (ELISA) for the quantification of porcine hemoglobin (PHb) in raw meat products. Before assay development, two mAbs immunoreactive to PHb ß subunit with different epitopes were characterized. The optimized immunoassay was specific to PHb and had a wide PHb working range from 15.6 µg/mL to 3,000 µg/mL and high reproducibility with low coefficient of variations (CV < 20%). Through this assay, the estimated PHb residuals in pork loin and shoulder meats were 0.4 mg/g and 1.1 mg/g, respectively. In addition, this immunoassay could effectively quantify PHb in laboratory-spiked meats (pork loin, pork shoulder, and turkey breast) with acceptable recovery. Overall, this is the first mAb-based sandwich ELISA that is suitable for the government, food industry, and third-party authority to monitor PHb residuals or porcine blood adulteration in raw pork and pork-free meat products.

Effects of nZVI dosing on the improvement in the contaminant removal performance of constructed wetlands under the dye stress.

In this study, different dosages of nanoscale zero-valent iron (nZVI) were used to improve the nitrogen removal efficiency in CWs under different C/N ratios and dye stress conditions. The addition of nZVI enhanced the dye and nitrogen removal efficiencies in constructed wetlands (CWs) through chemical reduction and biological denitrification processes. However, total nitrogen (TN) and dye removal efficiencies firstly increased and then decreased with the increases of the nZVI dosage and influent COD/N (C/N) ratio. Under the influent C/N ratio of 5, the higher TN removal efficiencies (80.2%, 55.1%, and 69.14% under 25 mg/L, 50 mg/L, and 75 mg/L dye concentration, respectively) and higher COD removal efficiencies (48.3%, 74.95%, and 30.76% under 25 mg/L, 50 mg/L, and 75 mg/L dye concentration, respectively) were obtained in CWs by adding the optimal nZVI dosage (0.1 g/L). The dye removal efficiencies in CWs with nZVI at C/N = 1 (75%-91%) and at C/N = 5 (81%-97%) were all significantly higher than that in CWs without nZVI (60%-82%). Moreover, the functional bacteria for nitrogen removal in denitrification and the dye degradation (Zoogloea and Acinetobacter) were enriched in CWs with 0.1 g/L nZVI.

Challenges in SERS-based pesticide detection and plausible solutions.

Surface-enhanced Raman spectroscopy (SERS) can be used for the detection of trace amounts of pesticides in foods to ensure consumer safety. In this perspective, we highlight the trends of SERS-based assays in pesticide detection and the various challenges associated with their selectivity, reproducibility, and nonspecific binding. We also discuss and compare the target analyte capture techniques, such as the use of antibodies, aptamers, and molecularly imprinted polymers (MIPs), coupled with SERS to overcome the drawbacks as mentioned above. In addition, issues related to the nonspecific binding of analytes and its potential solution are discussed.

Magnetic solid-phase extraction of tobacco-specific N-nitrosamines using magnetic graphene composite as sorbent.

Tobacco-specific N-nitrosamines are carcinogenic components in mainstream cigarette smoke. To explore tobacco-specific N-nitrosamine release levels in cigarettes, a magnetic solid-phase extraction procedure using magnetic graphene composite as sorbent for fast enrichment of tobacco-specific N-nitrosamine was developed. Under optimal conditions, a tobacco-specific N-nitrosamine determination method was successfully proposed by combining magnetic solid-phase extraction procedure and high-performance liquid chromatography coupled with tandem mass spectrometry. The method's limit of detection for tobacco-specific N-nitrosamines in mainstream cigarette smoke ranged from 0.018 to 0.057 ng/cigarette. Good linearities were obtained with correlation coefficients above 0.9992. The accuracies of tobacco-specific N-nitrosamines in a spiked mainstream cigarette smoke sample were from 89.3 to 109.4%, with a relative standard deviation of less than 11.2%. The proposed method has the merits of rapidity and high sensitivity. Finally, the method was successfully applied to tobacco-specific N-nitrosamine analysis in real samples.