scholarly journals Poly (α-Dodecyl γ-Glutamate) (PAAG-12) and Polylactic Acid Films Charged with α-Tocopherol and Their Antioxidant Capacity in Food Models

Antioxidants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 284 ◽  
Author(s):  
Juliana Villasante ◽  
Eva Codina ◽  
Gádor Indra Hidalgo ◽  
Antxon Martínez de Ilarduya ◽  
Sebastián Muñoz-Guerra ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Partition Coefficients ◽  
Protective Action ◽  
The Novel ◽  
Industrial Processing ◽  
Oil In Water ◽  
Food Applications ◽  
Thermal Stability Of ◽  
Hplc Analyses ◽  
Primary Oxidation

Poly (α-dodecyl γ-glutamate) (PAAG-12) was successfully synthesized from poly(γ-glutamic acid) (PGGA) according to Nuclear Magnetic Resonance (NMR) analyses. PAAG-12 films were prepared and enriched with 5% α-tocopherol, with the aim of using them as novel antioxidant active packaging for food applications. Thermogravimetric Analysis (TGA) characterization determined that α-tocopherol improved thermal stability of films, which is beneficial for industrial processing. Polylactic Acid (PLA) films prepared with the same amount of α-tocopherol were used to set a comparative frame and both types of films were applied to two different food models to assess their protective action against oxidation. Water, 50% ethanol (EtOH) and 95% EtOH were used as food simulants and HPLC analyses were performed to determine diffusion and partition coefficients in PLA and the novel polymer, the latter exhibiting slower release rates. Primary oxidation was measured with peroxide value, which revealed that PAAG-12 films with α-tocopherol protected oil-in-water (O/W) emulsions up to 29 days, complying with the Codex Alimentarius.

scholarly journals New Trends in Natural Emulsifiers and Emulsion Technology for the Food Industry

2021 ◽  
Author(s):  
Arantzazu Santamaria-Echart ◽  
Isabel P. Fernandes ◽  
Samara C. Silva ◽  
Stephany C. Rezende ◽  
Giovana Colucci ◽  
...  
Keyword(s):  
Circular Economy ◽  
Food Industry ◽  
Solid Particles ◽  
Microbial Fermentation ◽  
Bibliometric Data ◽  
Pickering Emulsions ◽  
Double Emulsions ◽  
Oil In Water ◽  
Food Applications ◽  
New Generation

The food industry depends on using different additives, which increases the search for effective natural or natural-derived solutions, to the detriment of the synthetic counterparts, a priority in a biobased and circular economy scenario. In this context, different natural emulsifiers are being studied to create a new generation of emulsion-based products. Among them, phospholipids, saponins, proteins, polysaccharides, biosurfactants (e.g., compounds derived from microbial fermentation), and organic-based solid particles (Pickering stabilizers) are being used or start to gather interest from the food industry. This chapter includes the basic theoretical fundamentals of emulsions technology, stabilization mechanisms, and stability. The preparation of oil-in-water (O/W) and water-in-oil (W/O) emulsions, the potential of double emulsions, and the re-emerging Pickering emulsions are discussed. Moreover, the most relevant natural-derived emulsifier families (e.g., origin, stabilization mechanism, and applications) focusing food applications are presented. The document is grounded in a bibliographic review mainly centered on the last 10-years, and bibliometric data was rationalized and used to better establish the hot topics in the proposed thematic.

scholarly journals Egg Yolk Oil as a Plasticizer for Polylactic Acid Films

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
María Carpintero ◽  
Ismael Marcet ◽  
Manuel Rendueles ◽  
Mario Díaz
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Light Transmission ◽  
Virgin Olive Oil ◽  
Antioxidant Properties ◽  
Egg Yolk ◽  
Extra Virgin Olive Oil ◽  
Vapour Permeability ◽  
Light Barrier ◽  
Food Applications

Polylactic acid (PLA) is known to be one of the most extensively used biodegradable thermoplastic polyesters, with the potential to replace conventional petroleum-based packaging materials; however, the low flexibility of films prepared using PLA has limited the applications of this biopolymer. In this study, in order to improve the mechanical properties of PLA films and to provide them with antioxidant properties, egg yolk oil was used as a biobased plasticizer. For this purpose, PLA films with increasing concentrations of egg yolk oil were prepared and the effects of this oil on the light transmission, transparency, colour, water vapour permeability, solubility, antioxidant activity and mechanical properties of the films were characterized. In addition, electron microscopy of the structure of the transverse section of the films was also performed. Results showed that the formulations with higher concentrations of egg yolk oil increased the films’ elasticity, and their light barrier and antioxidant properties. Finally, in order to test the films as a packaging material for food applications, extra virgin olive oil and resveratrol, both photosensitive compounds, were packed and exposed to ambient light. Overall, the results show the potential of egg yolk oil as an environmentally friendly plasticizer that can improve the flexibility of PLA films and provide them with additional photoprotective properties.

scholarly journals Study of the Synergistic Effect of Nanoporous Nickel Phosphates on Novel Intumescent Flame Retardant Polypropylene Composites

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shibin Nie ◽  
Chi Zhang ◽  
Chao Peng ◽  
De-yi Wang ◽  
Daowei Ding ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Intumescent Flame Retardant ◽  
The Novel ◽  
Polypropylene Composites ◽  
Pp Composites ◽  
Flame Retardant Properties ◽  
Microencapsulated Ammonium Polyphosphate ◽  
Thermal Stability Of ◽  
Nickel Phosphates ◽  
Limited Oxygen

A char forming agent (CFA) and silica-gel microencapsulated ammonium polyphosphate (Si-MCAPP) were selected to form novel intumescent flame retardant system to prepare flame retardant polypropylene (PP) composites, and then the influences of nanoporous nickel phosphates (NiP) on the thermal and flame retardant properties of flame retardant PP composites were studied by the real time FTIR (RTFTIR) spectra, limited oxygen index (LOI) test, and the scanning electron microscopy. RTFTIR shows the addition of NiP can improve the thermal stability of flame retardant PP composites. LOI test shows LOI value is increased with the increase of the content of NiP, and the optimized concentration of NiP is 1.0%. Furthermore, smoke toxicity of the novel flame retardant PP composites was studied by mice experiment. The upper limit of the no death smoke concentration of the composite is 12.37 mg/L.

Effect of Chemistry Modification, Hot Forging and Partitioning on Low Alloy Grade Tool Steel

2018 ◽  
Vol 786 ◽  
pp. 75-83
Author(s):  
Ahmed Ismail Zaky Farahat ◽  
Mohamed Kamal El Fawkhry ◽  
Ayman M. Fathy ◽  
Taha M. Mattar
Keyword(s):  
Thermal Stability ◽  
Tool Steel ◽  
Retained Austenite ◽  
Treatment Process ◽  
Hot Forging ◽  
Optical Microscope ◽  
Isothermal Treatment ◽  
The Novel ◽  
Slow Cooling ◽  
Thermal Stability Of

Development of S6 tool steel has been discussed in this research by conducting a bit modification in the chemical composition using aluminum instead of molybdenum, and micro addition of boron to enhance the marteniste structure. Then, the hardenability and thermal stability have been detected in regarding to S6 tool steel. A novel isothermal treatment process has been suggested to enrich the retained austenite, and thereby, it has been tracked by using XRD, optical microscope, and SEM in conjugation with EDS. The effect of retained on the mechanical properties has been determined. The results ensure that aluminum has inhibited the graphite formation through the slow cooling regime. No change of hardenability or thermal stability of S6 tool steel triggered from adding of aluminum and microaddition of boron. In addition, the novel isothermal process leads to enrichment of retained austenite that has significantly affected on the combination of ductility with strength of the newly designed steel.

Preparation and properties of propargyl ether-terminated poly(imide siloxane)s and their composites

2020 ◽  
pp. 095400832095452
Author(s):  
Qing Ye ◽  
Qiaolong Yuan ◽  
Farong Huang
Keyword(s):  
Flexural Strength ◽  
Thermomechanical Analysis ◽  
Proton Nuclear Magnetic Resonance ◽  
Aromatic Diamine ◽  
The Novel ◽  
H Nmr ◽  
Chemical Structures ◽  
Propargyl Ether ◽  
Poly Imide ◽  
Thermal Stability Of

The novel propargyl ether-terminated oligo(imide siloxane)s (PTISs) based on 2,2’-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), aminopropyl-terminated polydimethylsiloxane (APPS), 4,4’-diaminodiphenylmethane (MDA) and p-aminophenyl propargyl ether (APPE) were synthesized. The chemical structures of PTISs were characterized by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FTIR). The PTISs exhibited excellent solubility in organic solvent and had broad processing window. The T300 carbon fabric was used to reinforce the PTIS matrices and prepare the composites (T300CF/PTISs). The thermal stability of the cured PTISs was analyzed by thermogravimetric analysis (TGA). The dynamic thermal mechanical properties of the composites were measured by dynamic thermomechanical analysis (DMA). The results show that the temperature at 5% weight loss (Td5) and residual yield at 800°C (Yr800°C) of the cured PTISs in N2 increase with incorporation of the aromatic diamine, whereas the Yr800°C of the cured PTISs in air decreases with introduction of the aromatic diamine. The elasticity of the composite increases with incorporation of the aromatic diamine, and the peak temperature of loss factor for the composites are higher than 300°C. The flexural strength, tensile strength and interlaminar layer shear strength (ILSS) of the T300CF/PTIS composite display the values of 439 MPa, 427 MPa and 32 MPa at room temperature, respectively. The retention of the flexural strength and ILSS for the T300CF/PTIS composite are above 80% at 250°C.

Calcium and Calmodulin Regulate Mercury-induced Phospholipase D Activation in Vascular Endothelial Cells

2009 ◽  
Vol 28 (3) ◽  
pp. 190-206 ◽  
Author(s):  
Alon Peltz ◽  
Shariq I. Sherwani ◽  
Sainath R. Kotha ◽  
Jessica N. Mazerik ◽  
Elizabeth S. O’Connor Butler ◽  
...  
Keyword(s):  
Cardiovascular Diseases ◽  
Phospholipase D ◽  
Vascular Endothelial Cells ◽  
Protective Action ◽  
Vascular Endothelial Cell ◽  
Mercury Chloride ◽  
Channel Blockers ◽  
Significant Finding ◽  
Vascular Endothelial ◽  
The Novel

Earlier, we reported that mercury, the environmental risk factor for cardiovascular diseases, activates vascular endothelial cell (EC) phospholipase D (PLD). Here, we report the novel and significant finding that calcium and calmodulin regulated mercury-induced PLD activation in bovine pulmonary artery ECs (BPAECs). Mercury (mercury chloride, 25 μM; thimerosal, 25 μM; methylmercury, 10 μM) significantly activated PLD in BPAECs. Calcium chelating agents and calcium depletion of the medium completely attenuated the mercury-induced PLD activation in ECs. Calmodulin inhibitors significantly attenuated mercury-induced PLD activation in BPAECs. Despite the absence of L-type calcium channels in ECs, nifedipine, nimodipine, and diltiazem significantly attenuated mercury-induced PLD activation and cytotoxicity in BPAECs. This study demonstrated the importance of calcium and calmodulin in the regulation of mercury-induced PLD activation and the protective action of L-type calcium channel blockers against mercury cytotoxicity in vascular ECs, suggesting mechanisms of mercury vasculotoxicity and mercury-induced cardiovascular diseases.

scholarly journals Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Chern Chiet Eng ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Hidayah Ariffin ◽  
Wan Md. Zin Wan Yunus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Analysis ◽  
Basal Spacing ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Thermal Stability Of

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

The Influence of Alkaline Treatment on Mechanical Properties and Morphology of Rice Husk Fibre Reinforced Polylactic Acid

2014 ◽  
Vol 911 ◽  
pp. 13-17 ◽  
Author(s):  
Abdullah Farah Dina ◽  
Sa’ad Siti Zaleha ◽  
Bonnia Noor Najmi ◽  
Ibrahim Nor Azowa
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Brittle Fracture ◽  
Polylactic Acid ◽  
Rice Husk ◽  
Alkaline Treatment ◽  
Distilled Water ◽  
Internal Mixer ◽  
Fesem Micrographs ◽  
Thermal Stability Of

This study focuses on the influence of surface treatment and fibre sizes on mechanical behavior, physical properties and morphology of rice husk fibre (RHF) reinforced polylactic-acid (PLA). Modified RHF was prepared by using 6w.t.% sodium hydroxide (NaOH) and distilled water. PLA composite reinforced with 25w.t.% volume fractions of modified RHF was mixed using the internal mixer and fabricated by the mini injection moulding. Tensile and flexural strength results showed that the PLA composite with 100, 200 and 500μm particles sizes of water treated fibre are much higher than those of alkaline treated. DSC measurement was performed and indicated that the Tg,Tmand ΔHmof PLA reduced after reinforcement with water treated and alkaline treated fibres. TGA results showed that the treatment reduced the thermal stability of the PLA. FESEM micrographs for flexural fractured surfaces of composites showed micro crack and pores due to brittle fracture of the PLA matrix adjacent to the fibre as a result of the brittle nature of the PLA resin.

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