Determination of phenolic profile and antioxidant activity of pistachio hull using high-performance liquid chromatography–diode array detector–electro-spray ionization–mass spectrometry as affected by ultrasound and microwave

The phytochemicals content and radical scavenging activity of pistachio (Pistacia vera L.) hull extract obtained by different solvents (water, ethanol, and butanol) were measured and compared. Water was selected as superior solvent. Ultrasound-assisted aqueous extraction of the hull by power ultrasound (35 kHz) was more efficient in ascending the phytochemicals content than the sonochemical ultrasonication (130 kHz). High-performance liquid chromatography-mass spectrometry showed increased amounts of vanillic acid, p-coumaric acid, naringenin, and catechin in ultrasound-assisted extracts. Post-extraction sonication declined significantly the phenolics amount and antioxidant property of the aqueous extract. Microwave-assisted extraction increased the phenolics and flavonoids content at extract in a power-dependent trend.     

Improving the functionality of biodegradable food packaging materials via porous nanomaterials

Non-biodegradability and disposal problems are the major challenges associated with synthetic plastic packaging. This review article discusses a new generation of biodegradable active and smart packaging based on porous nanomaterials (PNMs), which maintains the quality and freshness of food products while meeting biodegradability requirements. PNMs have recently gained significant attention in the field of food packaging due to their large surface area, peculiar structures, functional flexibility, and thermal stability. We present for the first time the recently published literature on the incorporation of various PNMs into renewable materials to develop advanced, environmentally friendly, and high-quality packaging technology. Various emerging packaging technologies are discussed in this review, along with their advantages and disadvantages. Moreover, it provides general information about PNMs, their characterization, and fabrication methods. It also briefly describes the effects of different PNMs on the functionality of biopolymeric films. Furthermore, we examined how smart packaging loaded with PNMs can improve food shelf life and reduce food waste. The results indicate that PNMs play a critical role in improving the antimicrobial, thermal, physicochemical, and mechanical properties of natural packaging materials. These tailor-made materials can simultaneously extend the shelf life of food while reducing plastic usage and food waste.     

Microstructural evolution of a commercial ultrafine alumina powder densified by different methods

The densification and grain growth of bodies made from a commercial ultrafine alumina powder was investigated. The primary powder was initially subjected to dry (uniaxial cold pressing) and wet shaping (slip casting), followed by conventional (CS)-, two step (TSS)-, and microwave (MS) sintering to explore the effect of each series of treatments on the densification and microstructural evolution of the specimens. It was demonstrated that a uniform microstructure with higher density would be obtained using the wet shaping method. In addition, microwave sintering was found to be more effective into the densification of the specimens and in yielding a finer grain structure. It is believed that the high heating rate and effective particle packing are responsible for the improvements in these properties. On this basis, it was also demonstrated that the fracture toughness of the samples increased significantly through the application of microwave sintering.     

Synthesis of silicon-substituted hydroxyapatite by a hydrothermal method with two different phosphorous sources

Silicon-substituted hydroxyapatite (Si-HA) with up to 1.8 wt% Si content was prepared successfully by a hydrothermal method, using Ca(NO₃)₂, (NH₄)₃PO₄ or (NH₄)₂HPO₄ and Si(OCH₂CH₃)₄ (TEOS) as starting materials. Silicon has been incorporated in hydroxyapatite (HA) lattice by partially replacing phosphate (PO₄³⁻) groups with silicate (SiO₄⁴⁻) groups resulting in Si-HA described as Ca₁₀(PO₄)_6−x(SiO₄)_x(OH)_2−x. X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), inductively coupled plasma AES (ICP-AES) and scanning electron microscopy (SEM) techniques reveal that the substitution of phosphate groups by silicate groups causes some OH⁻ loss to maintain the charge balance and changes the lattice parameters of HA. The crystal shape of Si-HA has not altered compared to silicon-free reference hydroxyapatite but Si-incorporation reduces the size of Si-HA crystallites. Based on in vitro tests, soaking the specimens in simulated body fluid (SBF), and MTT assays by human osteoblast-like cells, Si-substituted hydroxyapatite is more bioactive than pure hydroxyapatite.     

Polymerization of Triazolinediones with trans-3,3-Dichloro-1-phenyl-1-propene

The reaction of 4-phenyl-1,2,4-triazoline-3,5-dione (PhTD) ( 2 ) with trans-3,3-dichloro-1-phenyl-1-propene ( 4 ) was investigated at room and reflux temperatures in methylene chloride solution. Although the reaction is slow, it gives quantitative yield. This reaction leads to the formation of two 2:1 adducts via double Diels–Alder and Diels–Alder-Ene reactions in a ratio of about 1: 7. The major product was isolated by means of fractional crystallization as a pure compound and was characterized by infra-red (IR), ¹H nuclear magnetic resonance (NMR), ¹³C NMR, mass spectra and elemental analysis. The structure of the minor product was determined by IR and ¹H NMR. These compounds were used as models for the polymerization reactions. The reaction of bistriazolinediones (1,6-bis-(3,5-dioxo-1,2,4-triazoline-4-yl)hexane and bis-(p-3,5-dioxo-1,2,4-triazoline-4-ylphenyl)methane) with ( 4 ) was carried out in dimethylformamide (DMF). The reactions gave novel polymers via repetitive double Diels–Alder and Diels–Alder-Ene polyaddition reactions, with the major component being a Diels–Alder-Ene structure. These polymers have intrinsic viscosities in a range from 0·08 to 0·18dlg^-1 in DMF. The physical properties and structural characterization of these polymers have been studied and are reported. © of SCI.     

Synthesis and characterization of a novel silicone containing vinylic macromonomer and its uses in the preparation of poly (silicone‐co‐styrene‐co‐butylacrylate) with montmorillonite nanocomposite emulsion

A new silicone containing macromonomer, 4‐(methacrylamido) phenoxy polymethylhydrosiloxane (4‐MPMHS) with a vinyl group, was successfully synthesized. Then poly (silicone‐co‐styrene‐co‐butylacrylate) with montmorillonite, P (Si‐co‐St‐co‐BA) with MMT nanocomposite emulsion was prepared by in situ intercalative emulsion polymerization of styrene (St), butyl acrylate (BA), and 4‐MPMHS, in the presence of organic modified montmorillonite (OMMT) with different OMMT contents (0, 0.5, 1.0, 1.5, and 2 wt %). Potassium persulphate (KPS) was used as an initiator and sodium lauryl sulfoacetate (SLSA) and nonyl phenol ethylene oxide—40 U (NP‐40) were used as anionic and nonionic emulsifiers, respectively. The resulting macromonomer was characterized by elemental analysis, Fourier transformer infrared (FT‐IR), proton (¹H NMR), and carbon (¹³C NMR) nuclear magnetic resonance spectroscopes. The OMMT was characterized by FT‐IR and X‐ray diffraction (XRD). The nanocomposite emulsions were characterized by using Fourier Transform infrared spectroscopy (FT‐IR), laser light scattering, and surface tension method. Thermal properties of the copolymers were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and then the effects of OMMT percent on the water absorption ratio and drying speed were examined. Results showed that OMMT could improve the properties of emulsion. In other words, the properties of nanocomposite emulsions were better when compared with those of the silicone‐acrylate emulsion. The property of nanocomposite emulsion containing 1 wt % OMMT was the best one, and the following advantages were obtained: smaller particle size, faster drying speed, smaller surface tension, and improved water resistance by the incorporation of OMMT. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improving the dynamic performance of continuous-flow mixing of pseudoplastic fluids possessing yield stress using Maxblend impeller

The strategic approach of this article is to characterize the continuous-flow mixing of pseudoplastic fluids possessing yield stress in a stirred reactor with the Maxblend impeller. Dynamic experiments were carried out through the frequency-modulated random binary input of a brine solution to determine the extent of non-ideal flows. Mixing quality was determined on the basis of the extent of channeling and fully mixed volume. The effects of important parameters such as impeller speed (25–500 rpm), absence of baffles, fluid rheology (0.5–1.5%), fluid flow rate (3.20–14.17 L min⁻¹), and the locations of inlet/outlet on the dynamic performance of the continuous-flow mixing vessel were explored. The performance of the Maxblend impeller was then compared to the performances of various types of impellers such as close-clearance (an anchor), axial-flow (a Lightnin A320), and radial-flow (a Scaba 6SRGT) impellers. It was found when the channeling approached zero and the fully mixed volume approached the total fluid volume in the vessel, the power drawn by the A320 impeller and the Scaba impeller were about 2.9 and 4.3 times greater than that of the Maxblend impeller. Thus, the Maxblend impeller was able to drastically improve the performance of continuous-flow mixing with huge power savings. The mixing quality was further improved by optimizing the impeller speed, decreasing the fluid flow rate, decreasing the fluid concentration, and using bottom inlet- top outlet configuration. The flow non-ideality of the mixing system increased in the absence of the baffles. Thus, better mixing quality and more energy savings can be achieved by employing the findings of this study.