Applying a sandwich-like strategy for dual 'light up' capture and eradication of Staphylococcus aureus using magnetically functionalized materials.

In this study, we proposed an innovative application of porcine immunoglobulin G (IgG)-functionalized Fe3O4 (IgG-Fe3O4) specifically designed to target and capture Staphylococcus aureus (S. aureus). In addition, aminophenylboronic acid-modified tetraphenylethylene nanoparticles (APBA-TPE NPs) were utilized, establishing a sandwich-type dual recognition system via interactions with the bacteria's extracellular glycolipids. This approach enables highly sensitive and precise detection of bacterial presence, with a limit of detection (LOD) reaching down to 5.0 CFU/mL. Specifically, the prepared APBA-TPE NPs achieved 99.99% bacterial inactivation within 60 min at a concentration of 200 µg/mL. The results showed that APBA-TPE NPs possess a remarkable capacity for reactive oxygen species (ROS) production, which could attack the bacterial cell membrane, leading to bacterial lysis and content leakage, and ultimately to bacterial death. Furthermore, the material still showed good recoveries ranging from 88.5% to 93.5% in actual water samples, as well as a favorable sterilizing effect of killing all microorganisms for 60 min. This research provides new strategies and insights into the construction of methods for the specific capture, detection, and inactivation of S. aureus.

Film-forming properties and mechanisms of soy protein: Insights from ß-conglycinin and glycinin.

Extensive research has been conducted on soy protein films; however, limited information is available regarding the influence of the major components, ß-conglycinin (7S) and glycinin (11S), on the film-forming properties of soy protein. This study aimed to isolate the 7S and 11S fractions in order to prepare films and investigate the impact of varying 7S/11S ratios on the film-forming solutions (FFS) and film properties. The findings revealed that higher 11S ratios led to increased protein aggregation, consequently elevating the storage modulus (G') of the FFS. Notably, an optimal 7S/11S ratio of 7S1:11S2 (CF3) significantly enhanced the film's water resistance. Specifically, it enhanced the water contact angle by an impressive 17.44 % and reduced the water vapor transmission rate by 27.56 %. These improvements were attributed to intermolecular interactions, involving hydrogen bonds and salt bridges, between the amino acid residues of 7S and 11S. As a result, a more uniform and dense microstructure was achieved. Interestingly, the mechanical and optical properties of the film were maintained by the different protein fractions examined. In summary, this study contributes to the understanding of the film-forming properties of soy protein, particularly the role of 7S and 11S.

Breaking the temperature limitation of zein-rice starch dough by microwave pre-gelatinization: Morphological, structural and rheological properties of the dough.

Zein has gluten-like viscoelasticity, but its use is limited due to high glass transition temperature (Tg). To break the temperature limitation of zein-starch dough, microwave heating was used to pre-gelatinize a partial of the starch with zein, and then the remaining was added and kneaded to form a dough. Pre-gelatinized doughs formed by rice starch (PRS), zein-starch (PUZS), and extruded zein-starch (PEZS) were included in this study. The thermal, morphological, rheological, and secondary structural properties of the dough were investigated. The results showed that zein and starch formed a composite gel network and firmly bound starch granules, which improved the dough properties with a smooth surface and compact internal structure, increased strain tolerance, and decreased stiffness. Unextruded zein was distributed uniformly and had strong interactions with the starch. Extruded zein tended to form large particles and had limited interaction with starch but improved dough extensibility. Microwave pre-gelatinization increased the stability of the secondary structure of zein and maintained the viscoelasticity of dough below zein's Tg, which provided a safe and effective way to break the temperature limitation of zein as a structural protein used in foods.

Effect of electron beam irradiation on granular cold-water swelling chestnut starch: Improvement of cold-water solubility, multiscale structure, and rheological properties.

In this study, granular cold-water swelling (GCWS) starch was prepared from chestnut starch by ethanol-alkali method, after which it was further modified by electron beam irradiation (EBI) technique to investigate the effect of EBI on GCWS chestnut starch. It was shown that the alcohol-alkali treatment disrupted the starch double helix structure and the starch crystalline form had been changed from "C" to "V" type. On this basis, EBI continued to act on the disrupted starch chains and further cleaved the long chains into short chains, which significantly improved the solubility of starch to 90.08 % in cold water at a 24 kGy irradiation dose. Therefore, this study can broaden the application scope of starch and provide new ideas for GCWS starch applications in food and water-soluble pharmaceutical industries.

The role and mechanism of electron beam irradiation in glutaric anhydride esterified proso millet starch: Multi-scale structure and physicochemical properties.

To investigate the effect of electron beam irradiation (EBI) pretreatment on the multiscale structure and physicochemical properties of esterified starch, this study used EBI pretreatment to prepare glutaric anhydride (GA) esterified proso millet starch. GA starch did not show the corresponding distinct thermodynamics peaks. However, it had a high pasting viscosity and transparency (57.46-74.25 %). EBI pretreatment increased the degree of glutaric acid esterification (0.0284-0.0560) and changed its structure and physicochemical properties. EBI pretreatment disrupted its short-range ordering structure, reducing the crystallinity, molecular weight and pasting viscosity of glutaric acid esterified starch. Moreover, it produced more short chains and increased the transparency (84.28-93.11 %) of glutaric acid esterified starch. This study could offer a rationale for using EBI pretreatment technology to maximize the functional properties of GA modified starch and enlarge its implementation in modified starch.

Effect of screw speed, temperature and moisture on physicochemical properties of corn gluten meal extrudate.

BACKGROUND: Corn gluten meal (CGM) is the main by-product of corn starch with rich protein and dietary fiber. The extrusion of CGM with a twin-screw extruder aimed to expand the novel utilization of this plant-protein resource. The impacts of screw speed, extrusion temperature, and material moisture on physicochemical properties of the extrudates were assessed. RESULTS: The microstructure depicted a favorable fiber-like structure formed under screw speed 120-150 rpm, extrusion temperature 140-150 °C, and material moisture 40-45%. Expansion ratio, rehydration ratio, water solubility index, hardness, and chewiness increased until screw speed reached 120 rpm. With accelerating extrusion temperature, these indicators showed an overall increasing trend. As for material moisture, expansion ratio, hardness, and chewiness showed a decreasing trend. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that disulfide bonds were necessary for protein crosslinking during extrusion. CONCLUSION: It can be concluded that CGM is extrudable, whose textural and physicochemical properties vary as functions of the extruding parameters, providing diversity for its potential applications. © 2023 Society of Chemical Industry.

Comparative investigation of the effects of electron beam and X-ray irradiation on potato starch: Structure and functional properties.

Electron beam (particle radiation) and X-ray (electromagnetic radiation) without radioisotope in the application of material modification have received increasing attention in the last decade. To clarify the effect of electron beam and X-ray on the morphology, crystalline structure and functional properties of starch, potato starch was irradiated using electron beam and X-ray at 2, 5, 10, 20 and 30 kGy, respectively. Electron beam and X-ray treatment increased the amylose content of starch. The surface morphology of starch did not change at lower doses (< 5 kGy), but starch granules were aggregated with the increase of doses. All treatments decreased crystallinity, viscosity and swelling power but increased solubility and stability properties. The effects of electron beam and X-ray on the starch had a similar trend. Unlike X-ray, electron beam destructed the crystallinity of starch to a lesser extent, thereby increasing thermal stability and freeze-thaw stability. Furthermore, X-ray irradiation at higher doses (> 10 kGy) resulted in outstanding anti-retrogradation properties of starch compared with electron beam treatment. Thus, particle and electromagnetic irradiation displayed an excellent ability to modify starch with respective specific characteristics, which expands the potential application of these irradiations in the starch industry.

Comprehensive evaluation of the effect of five sterilization methods on the quality of black carrot juice based on PCA, TOPSIS and GRA models.

The effect of thermal pasteurization (TP), high temperature long time (HTLT), ultra-high temperature instantaneous (UHT), high hydrostatic pressure (HHP) and thermosonication (TS) sterilization on the physicochemical, sensory and functional properties of black carrot juice (BCJ) were studied. And for the first time, the comprehensive quality of sterilized BCJ was quantified by mathematical modeling. UHT was the least suitable sterilization method for BCJ resulting from the most severe deterioration in functional properties. TS had adverse effects on sensory and physicochemical properties, but significantly increased the total flavonoids and anthocyanins contents (p < 0.05) and showed the strongest antioxidant activity, making it a nutritional high-value processing method. TP and HHP balanced the improvement of sensory properties and the retention of functional properties, which were the most suitable sterilization methods for BCJ. This study determined the optimal sterilization methods of BCJ, and provided a scientific solution for the screening of high quality processing methods.

Pheophorbide-a as a Light-Triggered Liposomal Switch: For the Controlled Release of Alpinia galanga (A. galanga) Essential Oil and Its Stability, Antioxidant, and Antibacterial Activity Assessment.

In this study, Alpinia galanga essential oil liposomes (EO-Lip) were prepared with soybean lecithin and cholesterol as wall materials. A light-responsive liposome (EO-PLip) was designed for the controlled release of A. galanga oil based on the light-responsive properties of Pheophorbide-a. The dependence of Pheophorbide-a on illumination time was proved by UV spectroscopy. Characterization techniques such as UV spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy demonstrated that the essential oils were successfully encapsulated in liposomes. Moreover, the particle size of EO-PLip was 166.30 nm, the polydispersity index was 0.22, the zeta potential was -49.50 mV, and the encapsulation efficiency was 30.83%. Both EO-Lip and EO-Plip have high sustained-release effects on essential oil and showed light-responsive release characteristics under infrared stimulation. The prepared liposomes had good storage stability at 4 °C for 28 d. EO-PLip showed excellent transient antioxidant and bacteriostatic properties based on the ability to respond to light and slow release. This EO-PLip provided a platform for essential oils and might be used as a potent and controllable solution.

Effects of different cooking treatments on the sensory qualities and pigmented phytochemicals of carrots.

Effects of different cooking treatments including steaming (S), boiling (B), stir-frying (SF) and frying (F) on the sensory qualities and pigmented phytochemicals of "Guanghong" carrot were studied based on intelligent sensory technology and targeted metabolomics, with fresh carrot slices (R) as control. Results showed cooking treatments reduced the brightness, redness, yellowness, and color saturation, and h° was the core index reflecting consumers' preference for the color characteristics of cooked carrots. The overall acceptability of cooked carrots was higher than R, and S gave carrots the best taste. (E/Z)-phytoene, α-carotene and ß-carotene were the most dominant carotenoids monomers. None of the four cooking methods resulted in a loss of total monomer carotenoids content (TMCC) in carrots. B and SF increased the contents of xanthophyll and carotene, respectively, while the carotenoid esters's content remained stable during cooking. SF significantly increased TMCC and the contents of γ-carotene, α-carotene and (E/Z)-phytoene (p < 0.05). Pel-3-O-glu was the most important anthocyanins monomer in "Guanghong" carrot.

Electron beam irradiation application for improving the multiscale structure and enhancing physicochemical and digestive properties of acetylated naked barley.

The study used electron beam (EB) irradiation pretreatment to prepare acetylated (AC) naked barley starch. EB pretreatment enhanced the degree of substitution in acetylation from 0.027 to 0.109 %. The starch granules treated with EB and AC had a rough surface but maintained integrity. EB depolymerized the starch structure, providing opportunities for molecular rearrangement, thereby increasing the efficiency in the subsequent acetylation process. Therefore, EB pretreatment decreased AC starch amylose content (27.82 to 21.61 %), amylopectin molecular weight, relative crystallinity (31.04 to 26.23 %), short-range order, and increased amylose molecular weight comparing EB or AC-treated alone. These structural changes improve the properties of starch; thus, EB pretreatment reduced the thermal transition temperature, gelatinization enthalpy, pasting parameters, rapidly-digestible starch content (67.09-51.74 %), solubility, and improved content of slowly-digestible starch (23.82-36.65 %) and resistant starch (9.09-11.62 %). EB pretreatment can enhance efficiency and improve the structure and performance of acetylated modified starch.

Physicochemical properties and protein structure of extruded corn gluten meal: Implication of temperature.

Corn gluten meal is a by-product of corn starch production. To extend its application in the food industry, the extrusion of corn gluten meal was conducted, and the effects of temperature (80, 100, 120, and 140 °C) on physicochemical properties and protein structure of the extrudates were investigated. Corn gluten meal was texturized when the extrusion temperature reached 120 °C, and puffed when it reached 140 °C. With an increment of temperature from 120 to 140 °C, the bulk density, particle size, and zeta-potential of extrudates decreased (from 662.0 to 642.5 mg/cm3, 301.0 to 191.3 nm, and 4.82 to 1.52 mV). SDS-PAGE showed that disulfide bonds and other covalent bonds participated in protein cross-linking during extrusion. Thus, a model of temperature factor on protein reaction for texturization was proposed: With increase of extrusion temperature, the protein peptides got more unfolding; more covalent reactions occurred under higher temperature, which could be important for texturization.

Heat-induced aggregation of subunits/polypeptides of soybean protein: Structural and physicochemical properties.

To reveal the nature of thermal aggregation of soybean protein at subunit level, structure and physicochemical properties of αα'- and ß-subunits isolated from ß-conglycinin, acidic polypeptide, and basic polypeptide from glycinin, as well as ß-conglycinin and glycinin, were characterized before and after heat treatment. The transmission electron microscopy (TEM) images showed that ß-conglycinin, αα'-subunits and acidic polypeptide formed regular thermal aggregates, which exhibited high solubility, high ζ-potential value, and small particle size. While glycinin, ß-subunit, and basic polypeptide aggregated to insoluble clusters with large particle size distribution. The results of size exclusion chromatography and non-reducing electrophoresis showed that the disulfide bond was the important force in stabilizing the protein conformation of thermal aggregates in ß-conglycinin, glycinin, and their isolated subunits/polypeptides but ß-subunit. The results of surface hydrophobicity and intrinsic fluorescence spectra showed that the thermal aggregations of ß-subunit and basic polypeptide were mainly driven by hydrophobic interactions.

Impacts of extrusion temperature and α-subunit content on structure of zein extrudate and viscoelasticity of the plasticized network.

To elucidate the effects of temperature and α-subunit content on the physicochemical characteristics and structure of zein, three zeins (commercial zein, α-subunit-rich zein, and total zein) with high to low α-subunit content were extruded at 80, 100, 120, and 140 °C, respectively. The mechanical properties, peptide distribution, particular size, morphological changes in self-assembly, and intermolecular forces of the extrudates were determined; the extrudates were plasticized by acetic acid, and the rheological properties of the resulted viscoelastic network were measured. With the temperature increase, the solubility of zein extrudates decreased, and the peptide weight of α-subunit-rich zein and total zein increased. Excessive extrusion temperature negatively affected zein's ability to form viscoelastic plasticized networks. Zein with high purity of α-subunit tended to form a fibrous structure. In contrast, the existence of more non-α-subunits (ß-, γ-, and δ-zein) formed a compact one and strengthened the plasticized zein network. Therefore, α-subunit content and extrusion temperature could regulate the structures of zein extrudate or the viscoelasticity of plasticized networks to expand flexible utilization of zein in the food industry.

Application of zein in gluten-free foods: A comprehensive review.

The gluten-free food market is growing worldwide. Zein is a promising gluten substitute in the gluten-free system due to its similar viscoelastic properties to gluten. However, a few existing reviews are limited to the zein characteristics and the application of zein in gluten-free bread and noodles while lacking a comparison of basis information between zein and gluten and the application in other foods, like meat analogue. We compared the structure of zein and gluten at the molecular level to employ zein better in gluten-free food production. The application status of zein in gluten-free systems, the influencing factors of zein functionality, and the potential of zein in meat analogues were summarized comprehensively. The weak elasticity and insufficient gas retention ability are significant challenges for zein dough to produce desired bread. Additives and modifications, such as organic acids and thermal treatment, improve zein functionality by increasing the molecular flexibility or elasticity of the zein network. Future research still needs to focus on increasing zein-starch dough's elasticity and gas retention ability and decreasing zein's high glass transition temperature. Applying zein in meat analogues also requires more attention due to its ability to form fibrous texture.

Antibacterial aerogels with nano­silver reduced in situ by carboxymethyl cellulose for fresh meat preservation.

Bacterial cellulose (BC) was used as a reinforcing agent, citric acid (CA) as a cross-linking agent, and CMC@AgNPs as antibacterial nanomaterials, in which CMC@AgNPs were reduced from AgNO3 in situ by carboxymethyl cellulose (CMC) as a reducing agent and stabilizer to fight microbial corruption. Its potential application in packaging fresh meat has been investigated. Results showed that the antibacterial CMC@AgNPs/BC/CA aerogels with excellent structural integrity and outstanding water absorption were developed by adding 0.3% BC and 0.25% CA. The CMC@AgNPs/BC/CA aerogel significantly reduced the color change and the total viable bacterial counts (TVC) in fresh meat after 7 days of refrigerated storage. The results indicated that CMC@AgNPs/BC/CA aerogels can effectively extend the shelf life of fresh meat, and can be used for meat packaging as a biologically active absorption pad.

The role of the extension region on the structural and physicochemical characteristics of the α-subunit of ß-conglycinin: implications of pH value and ionic strength.

BACKGROUND: To clarify the role of the extension region on the structure-functional relationship of the α-subunit of ß-conglycinin, α-subunit and its segment of the core region (αc-subunit) were expressed via an Escherichia coli system. Their physicochemical properties were compared under acid, neutral or alkaline conditions (pH 4.0, 7.0, and 8.0) and high or low ionic strength (µ = 0.05 and 0.5), respectively. RESULTS: The results showed that the extension region contributed to increasing thermal stability, especially at low ionic strength under acidic and neutral conditions. The extension region stabilized the α-subunit with high solubility, low turbidity, and small particle size under neutral and alkaline conditions, whereas these impacts were suppressed at a high ionic strength and acidic conditions. Surface hydrophobicity of the α-subunit decreased under acidic and alkaline conditions without being interfered with by ionic strength. CONCLUSION: It can be concluded that the extension region played different roles under different pH and ionic strength conditions. These factors should be specified carefully and speculated individually to explore the more detailed and profound nature of ß-conglycinin at the submolecular level. The results could benefit a better understanding of the relationship between domain structure and functions of soybean protein. © 2022 Society of Chemical Industry.

Effect of potato flour on quality and staling properties of wheat-potato flour bread.

To elucidate the impact of potato flour (PF) on quality changes and staling characteristics of the composite bread from wheat-potato flour (WPF), the physicochemical (specific volume, colority, sensory value, texture, and viscosity) properties, and staling (X-ray diffraction and water migration) properties of bread were investigated. The quality of composite bread was comparable to wheat bread when addition level of PF at 20%, but decreased when the addition level increased to 30% or more, and became unacceptable at 50%. A chewy mouthfeel and an elastic and none-crumbly texture were observed on composite bread, which had higher hardness than wheat bread, and could keep on both longer linear distance and higher linear force during compression test. It indicated that such new parameters other than hardness should be introduced to coordinate with the texture quality of composite bread. During storage, the higher addition level of PF significantly decreased crystallinity of composite bread and slowed water migration rate from the crumb to crust, suggesting that PF had antistaling effect on composite bread, which was further emphasized by the fact that the setback value of the WPF decreased with the increase of PF addition.

Anti-inflammatory alkaloids from the root bark of Hernandia nymphaeifolia.

Four undescribed alkaloids, 7-ethoxy-6-methoxy-2-methylisoquinolin-1(2H)-one, 7,8-dihydroxy-6-methoxy-2-methylisoquinolin-1(2H)-one, N-formylhernagine, and 5,6-dihydroxy-N-methylphthalimide, were obtained from the root bark of Hernanadia nymphaeifolia, along with fourteen known compounds. The structures of these compounds were determined through spectroscopic and MS analyses. 7,8-Dihydroxy-6-methoxy-2-methylisoquinolin-1(2H)-one, N-formylhernagine, 5,6-dihydroxy-N-methylphthalimide, oxohernagine, hernandonine, and N-trans-feruloylmethoxytyramine inhibited the superoxide anion (O2-) production (IC50 values ≤ 6.23 µg/mL) by neutrophils stimulated with formyl-L-methionyl-L-leuckyl-L-phenyl-alanine/cytochalasin B (fMLP/CB). Furthermore, 7,8-dihydroxy-6-methoxy-2-methylisoquinolin-1(2H)-one, N-formylhernagine, 5,6-dihydroxy-N-methylphthalimide, oxohernagine, and N-trans-feruloylmethoxytyramine inhibited fMLP/CB-induced elastase release with IC50 values ≤ 7.41 µg/mL. In addition, 7,8-dihydroxy-6-methoxy-2-methylisoquinolin-1(2H)-one, N-formylhernagine, oxohernagine, and N-trans-feruloylmethoxytyramine showed potent inhibition with IC50 values ≤ 28.55 µM, against lipopolysaccharide (LPS)-induced nitric oxide (NO) generation.

Kohn-Sham Theory of the Fractional Quantum Hall Effect.

We formulate the Kohn-Sham (KS) equations for the fractional quantum Hall effect by mapping the original electron problem into an auxiliary problem of composite fermions that experience a density dependent effective magnetic field. Self-consistent solutions of the KS equations demonstrate that our formulation captures not only configurations with nonuniform densities but also topological properties such as fractional charge and fractional braid statistics for the quasiparticles excitations. This method should enable a realistic modeling of the edge structure, the effect of disorder, spin physics, screening, and of fractional quantum Hall effect in mesoscopic devices.