Search

The presence of metal-based catalysts in polymers is one of the obstacles for their applications in food packaging and composting. The current processes for removing these compounds are not efficient; they involve several steps and use a large amount of organic solvents and acids. To tackle these issues, we developed a new green approach in which CO2 laden water was used for the extraction of these compounds from a commercial polymer, poly(propylene carbonate) (PPC). Although PPC has favourable properties for food packaging and many other applications, a high level of a metal-based catalyst remains in its matrix after the polymerization. Prior to the extraction process, the solubility of different metal-based compounds in CO2 laden water was measured. Our results demonstrated that at 160 bar and 40 °C the solubility of zinc adipate (ZnAA), zinc glutarate (ZnGA) and zinc methyl glutarate (ZnMGA) was 0.66 mg ml−1, 1.37 mg ml−1, and 1.54 mg ml−1, respectively. Therefore, we attempted to purify PPC containing 2450 ppm ZnGA residue using this technique. Our results demonstrated that CO2 laden water was able to remove nearly 90% of the catalyst from PPC at 70 bar and 45 °C in static mode extraction. The process developed in this study is superior to the current techniques as it not only reduced zinc residues 70% more than the conventional method in the absence of any organic solvent and acid, but it also enabled us to remove other impurities such as cyclic propylene carbonate (cPC). Therefore, this purification technique played a pivotal role in promoting the physico-chemical properties of PPC. For example, after the purification, the thermal decomposition temperature of PPC was shifted from 124 °C to 214 °C which is paramount for thermal processing such as hot-melt extrusion; its tensile modulus increased from 1 MPa to 1.4 MPa, which is critical for packaging and other applications. These results demonstrated that CO2 laden water is an efficient green solvent for removing metallic compounds from a polymer to the acceptable level recommended by environmental protection agencies for composting. It will also open an avenue for broadening the application of renewable polymers for food packaging to address major environmental issues. [ABSTRACT FROM AUTHOR]

Three one-dimensional mercury(II) complexes, [Hg 2(μ N,N-((Me 2N-Ba) 2Bn)(μ-X) 2X 2] n, where X = Cl ( I), Br ( II), and I ( III), (Me 2N-Ba) 2Bn = N,N′-bis(dimethylaminobenzylidene)butane-1,4-diamine, involving a bidentate Schiff base with a flexible spacer (=N-C-C-C-C-N=) were prepared under mild condition and characterized by elemental analyses (CHN), FT-IR, 1H & 13C-NMR spectroscopy. The crystal structure of II has been determined by X-ray single-crystal diffraction. Each Hg(II) center adopts a distorted [HgNBr 3] tetrahedron environment arising from two crystallographically equivalent (Me 2N-Ba) 2Bn Schiff base ligands. Each of ligands acts as N 2-bis-chelating ligand with the nitrogen atoms of two imine functions in anti-form leading to the dinuclear [Hg 2(μ N,N-(Me 2N-Ba) 2Bn)Br 2] groups. Such dinuclear [Hg 2(μ N,N-((Me 2Nvg-Ba) 2Bn)Br 2] groups are bridged two iodine anions (μ-Br) 2 to form a neutral 1D-chain mercury ( II) coordination polymer. [ABSTRACT FROM AUTHOR]

Lactoferrin (LAC) is an iron-binding glycoprotein found in mammalian secretion, such as milk and colostrum, which has several advantageous biological characteristics, such as antioxidant and antimicrobial activity, intestinal iron absorption and regulation, growth factor activity, and immune response. LAC is an active GRAS food ingredient and can be included in the food packaging/film matrix in both free and encapsulated forms to increase the microbial, mechanical, barrier, and thermal properties of biopolymer films. Additionally, LAC-containing films maintain the quality of fresh food and extend the shelf life of food products. This paper primarily focuses on examining how LAC affects the antimicrobial, antioxidant, physical, mechanical, thermal, and optical properties of packaging films. Moreover, the paper explains the attributes of films incorporating LAC within different matrices, exploring the interaction between LAC and polymers. The potential of LAC-enhanced food packaging technologies is highlighted, showcasing their promising applications in sustainable food packaging., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Monosodium glutamate (MSG) is used as a common food additive in some foods. However, based on our search and knowledge, no comprehensive study discussed the effect of MSG on the human gut microbiome. In this study, the effects of MSG on the gut microbiome, liver, and kidney were performed. Data were collected from databases including PubMed, Scopus, Web of Science, and ScienceDirect using the search strategy and keywords. Finally, 14 eligible studies were selected for systematic review. This study provides a new perspective on the effects of MSG on the gut flora, shedding light on the potential relationship between MSG intake and human health., Competing Interests: The authors declare that they do not have any conflict of interest., (© 2024 The Authors. Food Science & Nutrition published by Wiley Periodicals LLC.)

Background: Due to the benefits of blenderized tube feeding (BTF) diets, the interest in using them is increasing. This study aimed to design BTFs for children and investigate their physicochemical and microbial properties, as well as Dietary Inflammatory Index (DII)., Methods: Five BTF diets were formulated mainly with fresh foods; their DII, physical (viscosity), and chemical (moisture, ash, protein, fat, energy, and micronutrients) characteristics were assessed. Also, the Hazard Analysis and Critical Control Points (HACCP) system was implemented for quality assurance of preparation, storage, and delivery of BTFs to patients in hospital. The microbial contamination (total count, Salmonella, Escherichia coli, Bacillus cereus, Listeria monocytogenes, coliforms, Staphylococcus aureus coagulase positive, mold, and yeast) was analyzed., Results: Energy and percentages of protein, fat, and carbohydrate in BTFs were in the range of 103-112 kcal/100 ml, 16%-22%, 28%-34%, and 48%-52%, respectively. The viscosity of the five developed BTFs was between 29 and 64 centipoises, which allows the formulas to flow without syringe pressure. The DII of all BTFs was between -0.73 and -2.24. Due to the implementation of HACCP, monitoring the production line of BTFs, and performance of corrective measures, no microbial contamination was observed by indicator pathogenic microorganisms., Conclusion: A planned BTF diet can be an excellent selection for children using enteral nutrition with tube feeding especially when they are made from fresh and anti-inflammatory foods such as recipes prepared in this study., (© 2022 American Society for Parenteral and Enteral Nutrition.)

Foodborne parasites in raw vegetables could cause parasitic infections in humans. An effective approach to the reduction of pathogenic microorganisms in vegetables involves identifying the main sources of contamination and the ecology of the involved microorganisms. This review aimed to evaluate the prevalence of foodborne parasites in raw vegetables in Iran. According to the reviewed studies, the prevalence rate of Ascaris spp., Giardia spp., Toxocara spp., Fasciola , Trichuris , Cryptosporidium , Dicrocoeliasis , Taenia spp., and Entamoeba histolytica was 6 % (95 % CI: 5-8 %), 6 % (95 % CI: 5-7 %), 6 % (95 % CI: 4-7 %), 2 % (95 % CI: 1-2 %), 1 % (95 % CI: 1-2 %), 10 % (95 % CI: 6-15 %), 2 % (95 % CI: 1-3 %), 5 % (95 % CI: 4-6 %), and 3 % (95 % CI: 2-4 %), respectively. According to the standard deviation map, Ilam province was one of the high-risk areas in terms of food-borne parasites in raw vegetables (3 SD < prevalence < 4 SD). Given the key role of raw vegetables in human parasitic contamination, governments must implement more stringent programs for effective wastewater treatment, preventing domestic and wild animals from entering farms, not using human and animal manure on farms, using ready-to-eat packaged vegetables, food safety training for households, implementation of GMP and HACCP in the factory vegetable packaging are required in this regard, especially in the high-risk areas of Iran, such as Ilam province., Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-021-00714-w., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© Springer Nature Switzerland AG 2021.)

Solanesol, the precursor for the synthesis of coenzyme Q10, is currently recovered from tobacco leaves by conventional extraction techniques that require multiple purification steps and a large amount of organic solvents. We recently identified tomato leaves as an alternative source of solanesol and hypothesized that a high-pressure CO 2 extraction could be used as a clean extraction process. The effect of CO 2 pressure and temperature on the extraction of solanesol was determined to achieve high yield and purity. It was found that solanesol could be extracted efficiently by subcritical CO 2 at 25 °C from tomato leaves. The extract contained 40% solanesol and other active compounds such as vitamin K1. A higher level of purity of 93% was achieved using a secondary purification step. Different conventional methods for solanesol extraction was compared to determine the most efficient technique for production of solanesol from tomato leaf. The highest yield of solanesol was achieved at nearly 1% dry weight with using subcritical CO 2 , which was superior to conventional methods.

We investigated the mechanism of luciferase immobilization on a solid surface through therphtalaldehyde in order to understand the role of this linker on stability and activity of luciferase. Metal organic frameworks (MOFs) are capable supports for the stabilization of some proteins and biomolecules, therefore, in this context for the first time, we report a light emmiting enzyme immobillization on one of these supports and then outline chemical developments in this process. To this end, Fe-MIL-88(NH2) was used to immobilize native luciferase and therphtalaldehyde linker was attached to the framework as an activated group. Interestingly, high loading capacity was observed in both bonding mechanisms. Furthermore, thermal stability and kinetic properties were improved very much but, thermodynamic/kinetic results and bonding efficiency is much better in the modified-MOF than native MOF. It was found that Schiff base mechanism between aldehyde as an active functional group in MOF and amine groups of enzyme led to the formation of imine bond. The surface chemical structure and morphologies of Fe-MIL-88(NH2) were characterized by FTIR, X-ray diffraction, Brunauer-Emmett-Teller (BET), FE-SEM, and TEM. In conclusion, using Fe-MIL-88(NH2) as a support to immobilize luciferase established simple immobilization process of luciferase with and without linker and it improved the remaining activity significantly., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Antimicrobial photodynamic therapy (aPDT) has emerged as one of the promising non-invasive adjuvant treatments of endodontic infections. The key part of this technique is application of an optimized nontoxic photosensitizer (PS), like indocyanine green (ICG) which when activated by light can destroy bacterial contaminants. Notwithstanding all featured properties of ICG, this PS mainly suffers from the lack of stability and concentration-dependent aggregation. A variety of nanomaterials (NMs) has been widely exploited to improve the stability and efficiency of ICG. The objective of this study was to evaluate and compare the efficiency of three high capacious metal organic frameworks (MOFs) to produce MOF-ICG as novel PSs improving ICG loading, stability and antimicrobial activity. This is first report on ICG-loaded MOFs for aPDT against endodontic infections., Materials and Methods: Three different nano-MOFs were synthesized (denoted as Fe-101, Al-101 and Fe-88), and employed for ICG loading (MOF-ICG). The stability of immobilized ICG, antimicrobial and anti-biofilm properties of MOF-ICG against Enterococcus faecalis (E. faecalis) as one of the main factors of endodontic infections as well as expression ratio of the esp gene in E. faecalis were evaluated., Results: Fe-101 and Al-101 showed acceptable ICG loading (ICG loading capacity of 16.93 ± 0.32 and 18.17 ± 0.31, respectively) as well as considerable enhanced aqueous stability (percent of degradation were only 14% and 17%, respectively) in comparison to free ICG (percent of degradation was 95%) after 10 days. ICG-free MOFs could surprisingly suppress the viability of E. faecalis after laser irradiation up to 18.1%, 28.8%, and 38.3% for Al-101, Fe-88 and Fe-101, respectively. ICG loaded MOFs mediated aPDT could significantly reduce the count of E. faecalis to 60.72%, 45.12%, and 62.67%, respectively (p < 0.05). The Fe-88-ICG-PDT, Fe-101-ICG-PDT and Al-101-ICG-PDT considerably dropped the biofilm formation of E. faecalis by 37.54%, 47.01% and 53.68% (p < 0.05). The expression of esp gene was also remarkably declined to 4.4-, 6.0- and 6.2-fold after aPDT in the presence of Fe-88-ICG, Al-101-ICG and Fe-101-ICG, respectively (P < 0.05)., Conclusion: Owing to the significant features of the Fe-101 including acceptable ICG loading and stability, as well as reasonable antimicrobial effect after ICG loading in comparison to free ICG, it could be considered as a promising nano-PSs in aPDT to remove E. faecalis., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Newly, magnetic nanoparticles have extensively been used as alternative catalyst supports, in the view of their high surface area which results in high catalyst loading capacity, high dispersion, low toxicity, environmental preservation, distinguished stability, and suitable catalyst reusing. In the present study, the magnetite nanoparticles, NiFe 2 O 4 @Ag and NiFe 2 O 4 @Mo, were synthesized and characterized. The antimicrobial activities and catalytic properties of synthesized nanoparticles were tested afterwards. For synthetizing the nanoparticle NiFe 2 O 4 @Ag, silver ions were loaded onto the surface of the modified NiFe 2 O 4 and reduced to silver crystal by adding NaBH 4 . The antibacterial effects of NiFe 2 O 4 @Ag were examined against two species of soil and plant related bacteria named Bacillus subtilis (gram positive) and Pseudomonas syringae (gram negative), respectively. The antifungal activity of this nanoparticle was evaluated against two species of plant pathogenic fungi called Alternaria solani and Fusarium oxysporum. Biological results indicated that the synthesized material has shown an excellent antibacterial and antifungal activity against all examined bacteria and fungi so that, their growth were completely inhibited 24h after treatment with NiFe 2 O 4 @Ag. For the synthesis of a heterogeneous catalyst NiFe 2 O 4 @Mo, complex Mo(CO) 6 was loaded onto the surface of the modified NiFe 2 O 4 nanoparticle. This catalyst was found as an efficient catalyst for epoxidation of cis-cyclooctene and a wide variety of alkenes, including aromatic and aliphatic terminal ones using tert-butyl hydroperoxide as oxidant. This new heterogenized catalyst could easily be recovered by using a magnetic separator and reused four consecutive and loss only 13% of its catalytic activity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The rheological properties of wet powder masses used in the preparation of pharmaceutical pellets by extrusion/spheronization were evaluated utilizing capillary and rotational rheometers. A ram extruder was used as a capillary rheometer to construct flow and viscosity curves for each wet mass under different extrusion rates and die geometry. As a result, shear thinning behavior was observed for all wet masses. Among the considered rheological models Power Law and Herschel-Bulkley models fitted well with the experimental results. For the majority of the wet masses, water separation and migration occurred during extrusion which led to uneven water content in the extrudate. The effect of extrusion condition including extrusion speed, die geometry and water content on the occurrence of water separation was investigated and the surface quality of the extrudates was compared. In addition, dynamic rheometry tests were done by a parallel plate rheometer to investigate the viscoelastic properties of the wet masses. The frequency sweep tests showed that as water content of the wet masses decreases storage (G') and loss modulus (G″) increase. The storage modulus values were much higher than those of the loss modulus showing dominated elastic rather than viscous behavior for the wet masses at low deformation rates.

In this study melt rheological behavior of lactose-filled polyethylene glycol (PEG) composites as a low melting polymeric carrier for controlled release drugs was investigated using a capillary rheometer. The effect of lactose concentration and process variables such as temperature and ram speed on the flow behavior of PEG has been studied. The composites were found to be shear thinning in behavior when extruded, and the results were well described by power-law model in each case. Stronger shear thinning behavior was observed by raising the filler concentration and decreasing the temperature, while the flow index has been decreased. In all compositions a significant increase in shear viscosity was found by an increase in the filler content. In fact, shear viscosity increased linearly by weight fraction of filler, but there was a dramatic increase after the filler content raised above 20 wt% of lactose which might be the result of the strong interaction among filler particles. Furthermore, decreasing the process temperature resulted in an increase in shear viscosity, and the temperature dependence of shear viscosity decreased as the shear rate increased. The extensional viscosity of composites was calculated in each case. The results showed that the ratio of the extensional viscosity to shear viscosity was in the range of 500-1200.

In the title compound, [CuI(C(12)H(9)BrN(2))(C(18)H(15)P)], the Cu(I) ion is bonded to one I atom, one triphenyl-phosphane P atom and two N atoms of the diimine ligand in a distorted tetra-hedral geometry. The Schiff base acts as a chelating ligand and coordinates to the Cu(I) atom via two N atoms. In the diimine ligand, the dihedral angle between the pyridine and bromo-phenyl rings is 19.2 (2)°. In the crystal, mol-ecules are connected by π-π stacking inter-actions between inversion-related pyridine rings [centroid-centroid distance = 3.404 (3) Å].

In this paper, we report a simple and sensitive on-line solid phase extraction system for the preconcentration and determination of Cu(II) by flame atomic absorption spectrometry (FAAS). This method is based upon the on-line retention of copper at pH 5.0 on a minicolumn packed with chloromethylated polystyrene modified by 1-phenyl-1,2-propanedione-2-oxime thiosemicarbazone (PPDOT) as a new solid-phase extraction (SPE) sorbent. The retained Cu(II) ions were eluted with 1.0M HNO(3), and transported directly to FAAS for determination. Several chemical and flow variables were studied and optimized for a quantitative preconcentration and determination of copper(II). At the optimized conditions, for preconcentration of 10.0 mL of a sample solution, a linear calibration graph was obtained over the concentration range of 3.00-120.0 μg L(-1) for Cu(II). The limit of detection (3σ), limit of quantification (10σ), and enrichment factor are 0.56 μg L(-1), 2.0 μg L(-1) and 41, respectively. The relative standard deviation (n = 6) at 20 μg L(-1) of Cu(II) is 2.0%. This method could be applied for determination of trace amounts of Cu(II) in water, soil, and food samples with satisfactory results., (Copyright © 2011 Elsevier B.V. All rights reserved.)

We measured kinetic parameters in vitro and directly analyzed aminoacylation and formylation levels in vivo to study recognition of Escherichia coli initiator tRNA mutants by E. coli Met-tRNA synthetase and Met-tRNA transformylase. We show that, in addition to the anticodon sequence, mutations in the "discriminator" base A73 also affect aminoacylation. An A73----U change has a small effect, but a change to G73 or C73 significantly lowers Vmax/Kappm for in vitro aminoacylation and leads to appreciable accumulation of uncharged tRNA in vivo. Significantly, coupling of the G73 mutation with G72, a neighboring-base mutation, results in a tRNA essentially uncharged in vivo. Coupling of C73 and U73 mutations with G72 does not have such an effect. Elements crucial for Met-tRNA transformylase recognition of tRNAs are located at the end of the acceptor stem. These elements include a weak base pair or a mismatch between nucleotides (nt) 1 and 72 and base pairs 2.71 and 3.70. The natures of nt 1 and 72 are less important than the fact that they do not form a strong Watson-Crick base pair. Interestingly, the negative effect of a C.G base pair between nt 1 and 72 is suppressed by mutation of the neighboring nucleotide A73 to either C73 or U73. The presence of C73 or U73 could destabilize the C1.G72 base pair at the end of an RNA helix. Thus, in some tRNAs, the discriminator base could affect stability of the base pair between nt 1 and 72 and thereby the structure of tRNA at the end of the acceptor stem.