A new model to accurately measure the radon exhalation rate from soil using AlphaGUARD.

Radon exhalation rate from soil is a critical factor in evaluating environmental radon levels. However, AlphaGUARD PQ2000PRO may have some sensitivity towards thoron, which can have a significant impact on radon measurement. The traditional radon exhalation models generally ignore the presence of thoron, leading to an overestimation of the radon exhalation rate from soil. To handle this issue, a new model was proposed based on an analysis of several previous studies on radon exhalation theories. To prove the feasibility of the model, the radon exhalation rate measurements were performed by two different types of detectors-AlphaGUARD PQ2000PRO and RAD7. The radon exhalation rate obtained by using the new model is in good agreement with that obtained by using the theoretical model of radon exhalation of RAD7 within one standard error. This new model can be applied to accurately measure radon exhalation rate from soil by the PIC detector (PQ2000PRO).

Design of intermittent continuous measurement of radon concentration in water.

The U.S. Environmental Protection Agency established the maximum contaminant level limit for radon concentration in drinking water as 11.1 Bq L-1. A new device based on the bubbling method with a 290 mL sample bottle was designed for intermittent continuous measurement of water radon concentration. A STM32 is used to control the switch of the water pump and the valves. The Water-Radon-Measurement software written in C# is to connect RAD7 and calculate the water radon concentration automatically.

Fish gelatin films incorporated with cinnamaldehyde and its sulfobutyl ether-ß-cyclodextrin inclusion complex and their application in fish preservation.

For food preservation, the packaging film needs to have higher antibacterial activity in initial phase and keep longer activity. In this study, cinnamaldehyde (CA) and its sulfobutyl ether-ß-cyclodextrin inclusion complex (CA/S) were used to fabricate fish gelatin antibacterial composite films. The addition enhanced the elongation at break and light barrier property of the films. Film forming solution incorporated with CA and CA/S presented the most excellent inhibition ratio against Pseudomonas aeruginosa, which was 98.43 ± 1.11% in initial period and still 82.97 ± 4.55% at 72 h. Further, the packaging solution of gelatin combined CA and CA/S effectively inhibited the growth of microorganisms during preservation of grass carp slices. Especially, the total volatile salt-based nitrogen (TVB-N) did not exceed 10 mg/100 g at the end of storage, indicating that the active coating could obviously extend the shelf life of fish muscle. This work provided a promising food packaging system with antimicrobial and environmentally friendly.

COMPARISON OF RADON EXHALATION RATE MEASUREMENTS ON REFERENCE DEVICE IN OPEN AND CLOSED LOOP BY ALPHAGUARD IN FLOW-THROUGH MODE.

Radon-222 (Rn-222) exhalation rate is vital for estimating radiation risk from many kinds of materials. AlphaGUARD measures the radon concentration based on the ionization chamber principle, which is currently recognized as a reference instrument to measure radon. In China, measurements of radon exhalation rate are performed by AlphaGUARD operated in flow-through mode on a reference device to verify measurement accuracy. These measurements are performed in both open and closed loop. AlphaGUARD can fast rapidly the variation of the radon concentration in the chamber, which is tightly pressed against the surface of the medium to accumulate the exhaled radon. When the model is used to obtain the radon exhalation rate, the radon exhalation rates obtained by nonlinear data fitting on the measured radon concentrations are similar to the reference value of the device. The difference of radon exhalation rate values of six measurements is small.

Evaluation and relationship analysis of pea protein on structure and heat-induced gel performance of myofibrillar protein.

BACKGROUND: Surimi products occupy a large market in the food industry, and the gel performance is an important index to evaluate them. Thus, it is of great significance and practical value to find better food ingredients to regulate the structure and gel performance of surimi products. In this study, we used pea protein (PP) to restructure fish myofibrillar proteins (MPs) to achieve regulation of protein gel performance. RESULTS: PP could enhance MP gel performance in terms of compressive strength, water-holding capacity, and some texture parameters. This may be the result of an increasing ß-sheet content and a decreasing trend in the α-helix content, along with enhancements in hydrophobic interactions, nonspecific associations, and ionic bonds in a mixed PP-MP gel. The compressive strength, texture, and water-holding capacity of MP gel were positively correlated with surface hydrophobicity, active sulfhydryl, turbidity, and ß-sheet of the mixed PP-MP system. CONCLUSION: The findings suggest that PP can regulate the gel performance by remodeling the structure of MP. The regulation and correlation analysis between gel performance, structure, and physicochemical properties were explored and established to provide a theoretical basis for improving the quality of surimi products. This study will broaden the application of PP in the field of food processing and provide theoretical guidance for the manufacture of new surimi products. © 2023 Society of Chemical Industry.

The structure, antioxidant activity, and stability of fish gelatin/chitooligosaccharide nanoparticles loaded with apple polyphenols.

BACKGROUND: Apple polyphenols (APs) with multiple biological effects have attracted extensive attention due to their broad opportunities for application. However, the use of APs is hampered by their instability in the face of environmental changes. Designing efficient carriers to improve the bioavailability of APs is the key to solving these problems. In this study, gelatin-chitooligosaccharide nanoparticles produced by the Maillard reaction (GCM) were fabricated to encapsulate AP, and the structure, antioxidant activity, and stability of the GMM-AP nanoparticle system were evaluated. RESULTS: The results of endogenous fluorescence spectrum, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction, and simultaneous thermal analysis confirmed structural changes and interactions between GCM and AP. Combination with GCM did not adversely affect the antioxidant properties of AP, and the GCM-AP nanoparticles possessed superior temperature and storage stability. In comparison with fish gelatin-apple polyphenol nanoparticles, the GCM-AP nanoparticles were more stable at a wider pH range, and were more resistant to the electrostatic shielding effect of NaCl. After simulating gastric digestion, the particle size and polydispersity index (PDI) of GCM-AP nanoparticles were almost unchanged. CONCLUSION: The findings suggest that GCM nanoparticles loaded with AP could be used as good carriers with good antioxidant activity and stability. This study therefore provides a theoretical foundation for the development and industrial application of food functional factors. © 2023 Society of Chemical Industry.

Development of fish gelatin-chitooligosaccharide conjugates through the Maillard reaction for the encapsulation of curcumin.

The poor water solubility, bioavailability and stability of bioactive compounds have become the bottleneck restricting their wide application, thus developing a functional carrier to realize the efficient encapsulation and activity improvement of active hydrophobic substances has become a research hotspot. In this work, a functional glycosylated fish gelatin (called FG-COS conjugates) carrier based on fish gelatin (FG) and chitooligosaccharide (COS) via Maillard reaction was developed. The functional carrier exhibited good antioxidant activity and high encapsulation of curcumin (Cur). Enhanced antioxidant effect of Cur loaded in FG-COS conjugates (called FG-COS-Cur nanoparticles) was achieved, showing remarkable UV protection on Cur and enhanced intracellular antioxidant activity of FG-COS-Cur nanoparticles. Remarkably, FG-COS-Cur nanoparticles increased the cell viability of H2O2-induced oxidative damage Caco-2 cells, drastically reduced the levels of reactive oxygen species (ROS) and lactate dehydrogenase (LDH), and significantly increased intracellular antioxidant enzyme activities, which all exhibited a dose-response relationship. These findings suggested that the FG-COS conjugates with intrinsic antioxidant activity could effectively encapsulate Cur and improved bioavailability for hydrophobic active molecules in functional food field.

Synergistic antibacterial activity and mechanism of action of nisin/carvacrol combination against Staphylococcus aureus and their application in the infecting pasteurized milk.

Synergistic antibacterial effect is a promising way to overcome the challenge of microbial contamination in food. In this study, we detected the synergistic interactions of nisin and carvacrol. The MIC of nisin and carvacrol against S. aureus were 60 and 125 µg/mL, respectively. The FICI and FBCI were 0.28125 and 0.09375, which suggested that the nisin/carvacrol combination presented synergistic antibacterial effect against S. aureus. The antibacterial activity of nisin/carvacrol combination was much higher than their individuals and the dose of antibacterials was obviously reduced. The combination could completely kill S. aureus within 8 h, accelerate the destruction of cell membrane, and inhibit formation of biofilm. Under the intervention of nisin, more CAR could enter cell to hunt intracellular targets, leading to an increase in intracellular antibacterial level. Besides, in the storage of pasteurized milk, the combinational treatment successfully inhibited microbial reproduction at 25 °C and 4 °C. Thus, the combination of nisin and carvacrol was a potential synergistic strategy for food preservation.

Synthesis, characterization, and biological activity of selenium nanoparticles conjugated with polysaccharides.

Nanoparticles with unique properties have potential applications in food, medicine, pharmacology, and agriculture industries. Accordingly, many significant researches have been conducted to develop novel nanoparticles using chemical and biological techniques. This review focuses on the synthesis of selenium nanoparticles (SeNPs) using polysaccharides as templates. Various instrumental techniques being used to confirm the formation of polysaccharide-SeNPs conjugates and characterize the properties of nanoparticles are also introduced. Finally, the biological activities of the synthesized SeNPs and the influence of structural factors of polysaccharides on the property of synthetic nanocomposites are highlighted. In general, the polysaccharides functionalized SeNPs can be easily obtained using sodium selenite as precursor and ascorbic acid as reductant. The final products having different particle size, morphology, and selenium content exhibit abundant physiological activities. Structural factors of polysacchairdes involving molecular weights, substitution of functional groups, and chain conformation play determinant roles on the properties of nanocomposites, resulting in different biological performances. The review on the achievements and current status of polysaccharides conjugated SeNPs provides insights into this exciting research topic for further studies in the future.

Acid-free preparation and characterization of kelp (Laminaria japonica) nanocelluloses and their application in Pickering emulsions.

Cellulose nanofibers (CNFs) from kelp were prepared by cellulase treatment with lengths greater than 3 µm. CNFs were further oxidized by TEMPO-oxidized system, and the lengths of the oxidized CNFs (TEMPO-CNFs) were 0.6-1 µm. AFM and TEM images showed that intertwined CNFs fibers were divided into individual nanofibrils. The crystallinity of TEMPO-CNFs increased to 66.5 %. TGA analysis indicated that TEMPO-CNFs were more sensitive to temperature than cellulose and CNFs. FT-IR spectra revealed no changes in the basic cellulose structures of CNFs and TEMPO-CNFs. In the sunflower oil/water (20/80, v/v) model emulsions, the oil droplet sizes were less than 20 µm in CNFs emulsions, which became smaller in TEMPO-CNFs emulsions. Delamination was found in CNFs emulsions after three days of storage. Addition of NaCl increased the volumes of TEMPO-CNFs emulsions but enlarged the oil droplets sizes. TEMPO-CNFs emulsions had the largest volume with smallest and most homogeneous oil droplets at pH 3. TEMPO-CNFs emulsions showed good stability after storage for 30 days. Further, TEMPO-CNFs could also emulsify 50 % (v/v) of sunflower oil. All these results indicated that TEMPO-CNFs can be used in preparing Pickering emulsions.

Development and physicochemical characterization of chitosan hydrochloride/sulfobutyl ether-ß-cyclodextrin nanoparticles for cinnamaldehyde entrapment.

In this work, the cinnamaldehyde (CA) loaded nanoparticles were synthesized by directly cross-linking chitosan hydrochloride (CSH) and sulfobutyl ether-ß-cyclodextrin (SBE-ß-CD). The CA/SBE-ß-CD inclusion complex was firstly prepared, and its highest encapsulation efficiency (EE) was 86.34%. Field Emission Scanning Electron Microscope results indicated that the inclusion complex showed massive aggregates with a coarse and fluffy texture and irregular surface. Then, the inclusion complex interacted with CSH to form nanoparticles. The EE of CA in nanoparticles was improved. Atomic force microscopy showed the nanoparticles had regular and spherical morphology. Fourier transform infrared spectroscopy analysis demonstrated that CA was mainly encapsulated in the inner place of CSH/SBE-ß-CD nanoparticles (CSNs). The enhanced thermal stability of the nanoparticles was found in differential scanning calorimeter. X-ray diffraction implied that CA-CSNs existed in the amorphous state. CA-CSNs had excellent slow release property. Further, the bacteriostatic effect of CA-CSNs was much better than that of CA and CSNs. All the results indicated that CSNs can be used as a promising carrier to encapsulate CA. PRACTICAL APPLICATIONS: CA is an effective antimicrobial and generally recognized as Safe-GRAS. CA also exhibits many other bioactivities and has been commonly used for digestive, cardiovascular and immune system diseases. However, CA is easy to be oxidized and volatilized during storage for poor water solubility. The nanoencapsulations display the capacities of enhancing solubility of bioactive compounds, protecting them from degradation, and prolonging their residence. In this manuscript, CA loaded nanoparticles were investigated. The results suggested that the nanoencapsulation could benefit for improving water solubility and stability of CA. This strategy could be helpful for its application and development in food preservation.

Hydroxyapatite-embedded monolithic column for selective on-line solid-phase extraction of adenosine triphosphate and its phosphorylated metabolites.

A novel hydroxyapatite-embedded monolithic column has been facilely prepared in a stainless-steel column with inner diameter of 2.1 mm by the strong adhesion of urea-formaldehyde (UF) resin and exploited as a sorbent for selective on-line solid-phase extraction (on-line SPE) of adenosine triphosphate and its phosphorylated metabolites. The composition for this preparation, including the amount of hydroxyapatite nanopowders and the porogen were investigated to obtain a suitable monolith with large surface area and satisfactory permeability. Owing to anion exchange interaction of hydroxyapatite and hydrophilic interaction of UF monolithic matrix, the prepared monolith showed good extraction efficiency and selectivity towards these phosphorylated analytes. Several parameters for on-line SPE, including ACN percentage in the sampling solution, collection time span, salt concentration of the eluent, sampling and elution flow rate, were optimized with respect to the extraction efficiencies of the target compounds. Under the optimized conditions, the LODs of the analytes were in the range of 0.01-0.04 µg/g, the recoveries in the spiked samples ranged from 78.3%-92.5% with RSDs <4.7%. Due to the excellent extraction ability towards phosphorylated compounds in practical samples, a simple on-line SPE-HPLC method using hydroxyapatite-embedded monolith as sorbent has been proposed for monitoring freshness of grass carp.

Biomimetic cartilage scaffold with orientated porous structure of two factors for cartilage repair of knee osteoarthritis.

A dual-layer biomimetic cartilage scaffold was prepared by mimicking the structural design, chemical cues and mechanical characteristics of mature articular cartilage. The surface layer was made from collagen (COL), chitosan (CS) and hyaluronic acid sodium (HAS). The transitional layer with microtubule array structure was prepared with COL, CS and silk fibroin (SF). The PLAG microspheres containing kartogenin (KGN) and the polylysine-heparin sodium nanoparticles containing TGF-ß1 (TPHNs) were constructed for the surface, transitional layer, respectively. The SEM result showed that the dual-layer composite scaffold had a double structure similar to natural cartilage. The vitro biocompatibility experiment showed that the biomimetic cartilage scaffold with orientated porous structure was more conducive to the proliferation and adhesion of BMSCs. A rabbit KOA cartilage defect model was established and biomimetic cartilage scaffolds were implanted in the defect area. Compared with the surface layer and transitional layer scaffolds group, the results of dual-layer biomimetic cartilage scaffold group showed that the defects had been completely filled, the boundary between new cartilage and surrounding tissue was difficult to identify, and the morphology of cells in repair tissue was almost in accordance with the normal cartilage after 16 weeks. All those results indicated that the biomimetic cartilage scaffold could effectively repair the defect of KOA, which is related to the fact that the scaffold could guide the morphology, orientation, and proliferation and differentiation of BMSCs. This work could potentially lead to the development of multilayer scaffolds mimicking the zonal organization of articular cartilage.

Isolation and Comparative Study on the Characterization of Guanidine Hydrochloride Soluble Collagen and Pepsin Soluble Collagen from the Body of Surf Clam Shell (Coelomactra antiquata).

The aim of this study was to characterize the collagens from the body of surf clam shell (Coelomactra antiquata). Guanidine hydrochloride and pepsin were used to extract collagens. Guanidine hydrochloride soluble collagen (GSC) and pepsin soluble collagen (PSC) were separately isolated from the body of surf clam shell. Results showed that the moisture, protein, carbohydrate, and ash contents of the body of surf clam shell were 82.46%, 11.56%, 3.05%, and 2.38%, respectively, but the fat content was only 0.55%. The yields were 0.59% for GSC and 3.78% for PSC. Both GSC and PSC were composed of α1 and α2 chains and a ß chain, however, GSC and PSC showed distinct differences from each other and the type I collagen from grass carp muscle on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). GSC and PSC contained glycine as the major amino acid and had imino acid of 150 and 155 residues/1000 residues, respectively. Fourier transform infrared spectroscopy (FTIR) spectra of GSC and PSC revealed the presence of a triple helix. The GSC appeared to have a dense sheet-like film linked by random-coiled filaments and PSC had fine globular filaments under scanning electron microscopy (SEM). The maximum transition temperature (Tmax) of GSC and PSC was 33.05 °C and 31.33 °C, respectively. These results provide valuable scientific information for the texture study and development of surf clam shell or other bivalve mollusks.

Preservative effects of fish gelatin coating enriched with CUR/ßCD emulsion on grass carp (Ctenopharyngodon idellus) fillets during storage at 4 °C.

This study investigated the effects of a novel edible coating combining fish gelatin with curcumin/ß-cyclodextrin (CUR/ßCD) emulsion on the quality of grass carp fillets (GCFs) during storage at 4 °C. For all samples, the quality parameters, including weight loss, pH, total volatile basic nitrogen (TVB-N), peroxide value (PV), thiobarbituric acid (TBA) value, SDS-PAGE, free amino acids (FAA), microbiological (total viable counts (TVC), Pseudomonas counts, yeasts and molds, and H2S-producing bacteria), color and sensorial characteristics, were tested periodically. The coatings containing CUR/ßCD emulsions exhibited better preservative effects than gelatin/ßCD coating. Therefore, fish gelatin coating enriched with CUR/ßCD emulsion can be used as an effective way to maintain the quality of GCF and extend its shelf life during storage at 4 °C.

Identification of an adaptor protein that facilitates Nrf2-Keap1 complex formation and modulates antioxidant response.

Nrf2 plays a key role in the protection of the body against environmental stress via inducible expression of detoxification and antioxidant enzymes. Keap1 functions as a sensor for oxidative and electrophilic stresses and promotes Nrf2 degradation via its E3 ligase activity. Modulation of the Nrf2-Keap1 pathway has been extensively explored as a strategy to combat against drug toxicity and stress-induced diseases. Here we report a new player that modulates the Nrf2-Keap1 pathway. PAQR3, a membrane protein specifically localized in the Golgi apparatus, negatively regulates the expression of an array of Nrf2 target genes and alters cellular level of reactive oxygen species. PAQR3 tethers Nrf2 and Keap1, but not small MAF proteins to the Golgi apparatus. PAQR3 interacts with both Nrf2 and Keap1 and facilitates the interaction of Nrf2 with Keap1. PAQR3 promotes ubiquitination and degradation of Nrf2. Disruption of PAQR3 interaction with Nrf2 and Keap1 by a synthetic peptide reduces Nrf2 ubiquitination and elevates expression of Nrf2 target genes. At the animal level, deletion of PAQR3 increases Nrf2 protein level and the expression of Nrf2 target genes. In conclusion, our study pinpoints that PAQR3 functions as an adaptor protein to promote Nrf2-Keap1 complex formation, thereby modulating the Nrf2-Keap2 pathway and playing an important role in controlling antioxidant response of the cell.

Heparan Sulfate Biosynthesis Enzyme, Ext1, Contributes to Outflow Tract Development of Mouse Heart via Modulation of FGF Signaling.

Glycosaminoglycans are important regulators of multiple signaling pathways. As a major constituent of the heart extracellular matrix, glycosaminoglycans are implicated in cardiac morphogenesis through interactions with different signaling morphogens. Ext1 is a glycosyltransferase responsible for heparan sulfate synthesis. Here, we evaluate the function of Ext1 in heart development by analyzing Ext1 hypomorphic mutant and conditional knockout mice. Outflow tract alignment is sensitive to the dosage of Ext1. Deletion of Ext1 in the mesoderm induces a cardiac phenotype similar to that of a mutant with conditional deletion of UDP-glucose dehydrogenase, a key enzyme responsible for synthesis of all glycosaminoglycans. The outflow tract defect in conditional Ext1 knockout(Ext1f/f:Mesp1Cre) mice is attributable to the reduced contribution of second heart field and neural crest cells. Ext1 deletion leads to downregulation of FGF signaling in the pharyngeal mesoderm. Exogenous FGF8 ameliorates the defects in the outflow tract and pharyngeal explants. In addition, Ext1 expression in second heart field and neural crest cells is required for outflow tract remodeling. Our results collectively indicate that Ext1 is crucial for outflow tract formation in distinct progenitor cells, and heparan sulfate modulates FGF signaling during early heart development.

Stability and absorption of anthocyanins from blueberries subjected to a simulated digestion process.

Numerous studies have shown that anthocyanins usually have better in vitro bioactivity than in vivo bioactivity. This may be due to physiochemical degradation during gastrointestinal digestion and their poor bioavailability in in vivo studies. Therefore, this study aims to investigate the effects of anthocyanin structure on their stability under simulated gastrointestinal digestion and to assess their absorption in the intestines using Caco-2 human intestinal cell monolayers. The results show that gastric digestion does not significant affect blueberry anthocyanins in terms of composition and antioxidative activity. However, approximately 42% of the total anthocyanin and 29% of the antioxidative activity were lost during intestinal digestion. Structural analysis indicated that fewer free hydroxyl groups and more methoxy groups in the B-ring improve anthocyanin stability. The absorption trials demonstrated that more hydrophobic anthocyanins have better absorption efficiency than more hydrophilic anthocyanins. Furthermore, the glycoside structure also determines the absorption efficiency of anthocyanins.

Purification and characterization of a gelatinolytic matrix metalloproteinase from the skeletal muscle of grass carp (Ctenopharyngodon idellus).

A gelatinolytic matrix metalloproteinase (gMMP) from grass carp skeletal muscle was purified by 30-70% ammonium sulphate fractionation and a combination of chromatographic steps including ion exchange on DEAE-Sephacel, gel filtration on Sephacryl S-200, and affinity on gelatin-sepharose. The molecular weight of the proteinase as estimated by SDS-PAGE was 70 kDa under non-reducing conditions. The enzyme revealed high activity from 30 to 50 °C, and the gelatin hydrolysing activity was investigated at a slightly alkaline pH range using gelatin as substrate. Metalloproteinase inhibitor EDTA completely suppressed the gelatinolytic activity, while other proteinase inhibitors did not show any inhibitory effect. Divalent metal ion Ca(2+) was essential for the gelatinolytic activity. Further, peptide mass fingerprinting obtained four fragments with 45 amino acid residues, which were highly identical to MMP-2 from fish species. The gMMP could effectively hydrolyse type I collagen even at 4 °C, suggesting its involvement in the texture softening of fish muscle during the post-mortem stage.

In vitro antiproliferative effect of a water-soluble Laminaria japonica polysaccharide on human melanoma cell line A375.

A water-soluble polysaccharide WPS-2-1, purified from Laminaria japonica, has been found to have antitumor activity. In this study, WPS-2-1 exhibited high anti-proliferative activity on A375 cells in a dosedependent manner. Further investigation indicated that WPS-2-1 induced A375 cells apoptosis. Moreover, WPS-2-1-induced apoptosis was associated with the alteration in expressions of Bcl-2 family proteins. Mitochonadrial apoptotic pathway was involved in WPS-2-1-induced apoptosis, which included the loss of mitochondrial membrane and activation of caspase-3/9. The results in this study suggested that WPS-2-1 could effectively inhibit proliferation of A375 cells in vitro and induce apoptosis via mitochondrial apoptotic pathway. It might serve as a potential antitumor agent.