Effects of multi-frequency ultrasound on physicochemical properties,structural characteristics of gluten protein and the quality of noodle

In this study, the influence of multi-frequency ultrasound irradiation on the functional properties and structural characteristics of gluten, as well as the textural and cooking characteristics of the noodles were investigated. Results showed that the textural and cooking characteristics of noodles that contain less gluten pretreated by multi-frequency ultrasonic were ultrasonic frequency dependent. Moreover, the noodles that contain a smaller amount of sonicated gluten could achieve the textural and cooking quality of commercial noodles. There was no significant difference in the cooking and texture characteristics between commercial noodles and noodles with 12%, 11%, and 10% gluten pretreated by single-frequency (40 kHz), dual-frequency (28/40 kHz), and triple-frequency sonication (28/40/80 kHz), respectively. Furthermore, the cavitation efficiency of triple-frequency ultrasound was greater than that of dual-frequency and single-frequency. As the number of ultrasonic frequencies increased, the solubility, water holding capacity and oil holding capacity of gluten increased significantly (p < 0.05), and the particle size was reduced from 197.93 ± 5.28 nm to 110.15 ± 2.61 nm. Furthermore, compared to the control group (untreated), the UV absorption and fluorescence intensity of the gluten treated by multi-frequency ultrasonication increased. The surface hydrophobicity of gluten increased from 8159.1 ± 195.87 (untreated) to 11621.5 ± 379.72 (28/40/80 kHz). Raman spectroscopy showed that the α-helix content of all sonicated gluten protein samples decreased after sonication, while the β-sheet and β-turn content increased, and tryptophan and tyrosine residues were exposed. Through scanning electron microscope (SEM) analysis, the gluten protein network structure after ultrasonic treatment was loose, and the pore size of the gluten protein network increased from about 10 μm (untreated) to about 26 μm (28/40/80 kHz). This work elucidated the effect of ultrasonic frequency on the performance of gluten, indicating that with increasing frequency combination increases, the ultrasound effect became more pronounced and protein unfolding increased, thereby impacting the functional properties and the quality of the final product. This study provided a theoretical basis for the application of multi-frequency ultrasound technology in the modification of gluten protein and noodle processing.     

高取代度淀粉磷酸酯的理化性质及结构表征

以磷酸二氢钠、磷酸氢二钠的混盐为酯化剂,干法制备高取代度木薯淀粉磷酸酯(CSP-HDS)。研究表明,取代度不同时,产物的表观粘度、糊透明度、凝沉性、冻融稳定性均不相同。与木薯淀粉相比,酯化反应后产物粘度增大,糊透明度、凝沉性及冻融稳定性得到改善。XRD分析表明酯化反应主要发生在淀粉分子的非结晶区,对结晶区破坏不明显;SEM分析显示酯化后大部分淀粉颗粒保持原来形貌,仅少数团粒受到侵蚀。     

Global physicochemical properties as activity discriminants for the mGluR1 subtype of metabotropic glutamate receptors

Metabotropic glutamate receptors (mGluRs) are important as candidate therapeutic targets for many neurological disorders. In the present work, the focus has been on the mGluR1 subtype, where agonists have a proconvulsant profile while antagonists exert anticonvulsant activity. Identification of molecular determinants for the inhibition of mGluR1 provides a new avenue for the discovery and development of novel anticonvulsant drugs. Spatial configuration of key groups alone cannot explain activation selectivity at this specific receptor subtype. In fact, all known agonists and antagonists acting at mGluR1 can accommodate the same critical moieties in a similar geometric arrangement that corresponds to the extended conformation of glutamate. Therefore, other factors must account for the differences in activation. This study presents the results of an analysis of a large suite of steric, topological, electrostatic, and thermodynamic molecular properties calculated for a representative set of potent mGluR1 agonists and antagonists. Global steric parameters and the total nonpolar area provide discrimination between the mGluR1 agonists and antagonists considered in the present work. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 2018–2027, 2001     

不同提取方法所得褐藻糖胶的理化性质比较

通过各种理化性质的测定,对不同提取方法所得褐藻糖胶进行了分析,乙醇沉淀法的测定结果为:总糖含量(76.00±9.00)%、硫酸根含量(11.33±0.47)%、岩藻糖含量(35.60±4.20)%、重均/数均分子量(3.42×104)/(1.21×104);高分子电解质沉淀法的测定结果为:总糖含量(70.00±11.00)%、硫酸根含量(10.80±0.58)%、岩藻糖含量(35.15±2.85)%、重均/数均分子量(1.15×105)/(5.88×104)。高分子电解质沉淀法所得褐藻糖胶粗品和纯化后褐藻糖胶,其高分子电解质残留量分别为(0.12±0.038)%和(0.022±0.002)%。结果表明,乙醇沉淀法所得产品质量优于高分子电解质沉淀法,但是高分子电解质沉淀法具有工艺简单、成本低,更适于工业化生产等优点。     

A Concise Review on the Physicochemical Properties of Biopolymer Blends Prepared in Ionic Liquids

An enhancement of environmental concern lately has improved the awareness of researchers in employing eco-friendly solvents for processing biopolymers. Recently, ionic liquids have been utilized to prepare biopolymer blends as they are non-volatile and recyclable. Biopolymers such as cellulose, chitin, chitosan, keratin, lignin, silk, starch, and zein are widely used for the preparation of biopolymer blends via dissolution in ionic liquids, followed by coagulation procedure. In this concise review, three types of ionic liquids based on imidazolium cations combined with different counter anions that are frequently utilized to prepare biopolymer blends are described. Moreover, three types of biopolymer blends that are prepared in ionic liquids were classified, specifically polysaccharide/polysaccharide blends, polysaccharide/polypeptide blends, and polysaccharide/bioplastic blends. The physicochemical properties of biopolymer blends prepared in different imidazolium-based ionic liquids are also concisely reviewed. This paper may assist the researchers in the polymer blend area and generate fresh ideas for future research.     

Understanding the Growth of Interfacial Reaction Product Layers between Dissimilar Materials

When one starts to analyze the evolution of the interfacial reaction product layers between dissimilar materials it is often found out that as the number of interacting species grows, the complexity of the analysis increases extremely rapidly. It may even appear that the task is just too difficult to be completed. In this article we present the thermodynamic-kinetic method, which can be used to rationalize the evolution of interfacial reaction layers and bring back the physics to the analyses. The method is conceptually very simple. It combines energetics—what can happen—with kinetics—how fast things take place. Yet the method is flexible enough that it can utilize quantitative and qualitative data starting from the atomistic simulations up to the experiments carried out with bulk materials. Several examples about how to utilize this method in material scientific problems are given.     

cis‐Dioxomolybdenum(VI) complexes with unsymmetric linear tetradentate ligands: syntheses,structures and bromoperoxidase activities

Reactions of [MoO₂(acetylacetonate)₂], 2‐((2‐(2‐hydroxyethylamino)ethylamino)methyl)‐4‐R‐phenols (H₂Lⁿ, n = 1–5 for R = H, Me, OMe, Cl and Br, respectively) and KOH in 1:1:2 mole ratio in methanol afford a series of complexes having the general formula cis‐[MoO₂(Lⁿ)] ( 1 , 2 , 3 , 4 , 5 ) in 81–86% yields. The complexes have been characterized using elemental analysis, spectroscopy (infrared, UV–visible, and ¹H NMR, ¹³C NMR and ¹³C‐DEPT NMR) and electrochemical measurements. The molecular structures of 1 , 2 , 3 , 4 have been determined using single‐crystal X‐ray crystallography. In each of 1 , 2 , 3 , 4 , the ONNO‐donor 6,5,5‐membered fused chelate rings forming (Lⁿ)²⁻ and the two mutually cis oxo groups assemble a distorted octahedral N₂O₄ coordination sphere around the metal centre. In the crystal lattice, each of 1 , 2 , 3 , 4 forms a one‐dimensional infinite chain structure via intermolecular N  H⋅⋅⋅O hydrogen bonding interactions. In cyclic voltammograms, the diamagnetic complexes display an irreversible metal‐centred reduction in the potential range −0.73 to −0.88 V (vs Ag/AgCl). The physicochemical data are consistent with a very similar gross molecular structure for all of 1 , 2 , 3 , 4 , 5 . All the complexes exhibit decent bromoperoxidase activities and are also able to effectively catalyse benzoin and methyl(phenyl)sulfide oxidation reactions. Copyright © 2015 John Wiley & Sons, Ltd.     

Physicochemical characterization of paramagnetic ionic liquids 1‐vinyl‐3‐alkylimidazolium tetrahalogenidoferrate(III) [VRIM][FeClmBr4 − m]

Using microwave‐assisted synthesis method, a series of paramagnetic ionic liquids comprising 1‐vinyl‐3‐alkylimidazolium VRIM⁺ cation and tetrahalogenidoferrate (III) FeCl_mBr_{4 ? m}^? anion were designed and synthesized. The structure was analyzed using ¹H NMR and Raman spectroscopy. Ultraviolet–visible absorption spectra, thermal stability, magnetic susceptibility, viscosity, ionic conductivity, and solubility were characterized. Results show that elongation of the alkyl chain leads to replacement of bromides with a small amount of chlorides in the anion, shifting of UV maximum absorption peaks to shorter wavelengths, reduction of ionic conductivity, and solubility in polar solvents, as well as increase in fluidity, magnetic susceptibility, and solubility in nonpolar solvents. Copyright © 2014 John Wiley & Sons, Ltd.     

Physicochemical and Rheological Properties of Novel Magnesium Salt-Polyacrylamide Composite Polymers

Two series of novel inorganic-organic composite polymers have been prepared through physical blending of magnesium chloride and magnesium hydroxide respectively with polyacrylamide aqueous solution. The physicochemical properties of the magnesium salt-polyacrylamide composite polymers were tuned by varying the ratio between the magnesium salt (e.g., magnesium chloride and magnesium hydroxide) and polyacrylamide. Characterizations of magnesium salt-polyacrylamide composite polymers were carried out via FTIR and TEM. Parameters such as solution conductivity and viscosity were also taken into account to characterize the physicochemical properties of the composite polymer aqueous solutions. Magnesium chloride-polyacrylamide (MCPAM) composite polymer aqueous solutions have a higher conductivity compared to magnesium hydroxide-polyacrylamide (MHPAM) composite polymer aqueous solutions. The viscosities of the MHPAM composite polymer aqueous solutions were found higher than MCPAM composite polymer aqueous solutions. The rheological properties of the composite polymer aqueous solutions were investigated using steady-state flow and oscillatory frequency sweep within the linear viscoelastic region. Shear-thinning effect was observed for both composite polymer systems when the shear rate increases. In oscillatory frequency sweep tests, both composite polymer systems show that the viscoelastic behaviors depend strongly on the magnesium salt concentrations. Viscous behavior was found to be dominant for both composite polymer systems.     

The Effect of Oil Components and Homogenization Conditions on the Physicochemical Properties of Zedoary Turmeric Oil Submicron Emulsions

Zedoary turmeric oil submicron emulsions were studied. The effects of the oil phase as a mixture (ternary) on the emulsion droplet size were investigated by means of the simplex lattice design. By optimizing the homogenization process and using only 1.2% soya lecithin, emulsions with 20% oil phase consisting of zedoary turmeric oil–MCT–soybean oil ratio of 0.5:0.25:0.25 with particle sizes in the range of 132–148 nm and moderate viscosity (3.6–4.0 mPa · s) could be prepared. These emulsions showed good stability over 6 months. This study showed the dominating influence of composition of the oil phase as well as the importance of the homogenizing conditions on processing and stability of the zedoary turmeric oil submicron emulsions.