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Journal ArticleDOI

The self-assembly, aggregation and phase transitions of food protein systems in one, two and three dimensions

04 Mar 2013-Reports on Progress in Physics (IOP Publishing)-Vol. 76, Iss: 4, pp 046601
TL;DR: This review will tackle the current understanding of protein aggregation in the framework of foods, which is possibly one of the broadest contexts, yet is of tremendous daily relevance.
Abstract: The aggregation of proteins is of fundamental relevance in a number of daily phenomena, as important and diverse as blood coagulation, medical diseases, or cooking an egg in the kitchen. Colloidal food systems, in particular, are examples that have great significance for protein aggregation, not only for their importance and implications, which touches on everyday life, but also because they allow the limits of the colloidal science analogy to be tested in a much broader window of conditions, such as pH, ionic strength, concentration and temperature. Thus, studying the aggregation and self-assembly of proteins in foods challenges our understanding of these complex systems from both the molecular and statistical physics perspectives. Last but not least, food offers a unique playground to study the aggregation of proteins in three, two and one dimensions, that is to say, in the bulk, at air/water and oil/water interfaces and in protein fibrillation phenomena. In this review we will tackle this very ambitious task in order to discuss the current understanding of protein aggregation in the framework of foods, which is possibly one of the broadest contexts, yet is of tremendous daily relevance.
Citations
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Journal ArticleDOI
TL;DR: In this article, the formation of transient species (OH?, NO2?, NO radicals) and long-lived chemical products (O3, H2O2,, ) produced by a gas discharge plasma at the gas?liquid interface and directly in the liquid was measured in dependence on the gas atmosphere (20% oxygen mixtures with nitrogen or with argon) and pH of plasma-treated water (controlled by buffers at pH 3.3, 6.9 or 10.1).
Abstract: The formation of transient species (OH?, NO2?, NO radicals) and long-lived chemical products (O3, H2O2, , ) produced by a gas discharge plasma at the gas?liquid interface and directly in the liquid was measured in dependence on the gas atmosphere (20% oxygen mixtures with nitrogen or with argon) and pH of plasma-treated water (controlled by buffers at pH 3.3, 6.9 or 10.1). The aqueous-phase chemistry and specific contributions of these species to the chemical and biocidal effects of air discharge plasma in water were evaluated using phenol as a chemical probe and bacteria Escherichia coli. The nitrated and nitrosylated products of phenol (4-nitrophenol, 2-nitrophenol, 4-nitrocatechol, 4-nitrosophenol) in addition to the hydroxylated products (catechol, hydroquinone, 1,4-benzoquinone, hydroxy-1,4-benzoquinone) evidenced formation of NO2?, NO? and OH? radicals and NO+ ions directly by the air plasma at the gas?liquid interface and through post-discharge processes in plasma-activated water (PAW) mediated by peroxynitrite (ONOOH). Kinetic study of post-discharge evolution of H2O2 and in PAW has demonstrated excellent fit with the pseudo-second-order reaction between H2O2 and . The third-order rate constant k?=?1.1???103?M?2?s?1 for the reaction was determined in PAW at pH 3.3 with the rate of ONOOH formation in the range 10?8?10?9?M?s?1. Peroxynitrite chemistry was shown to significantly participate in the antibacterial properties of PAW. Ozone presence in PAW was proved indirectly by pH-dependent degradation of phenol and detection of cis,cis-muconic acid, but contribution of ozone to the inactivation of bacteria by the air plasma was negligible.

845 citations

Journal ArticleDOI
TL;DR: This review will discuss recent progress made in the field of functional and artificial amyloids and highlight connections between protein/peptide folding, unfolding and aggregation mechanisms, with the resulting amyloid structure and functionality.
Abstract: Self-assembled peptide and protein amyloid nanostructures have traditionally been considered only as pathological aggregates implicated in human neurodegenerative diseases. In more recent times, these nanostructures have found interesting applications as advanced materials in biomedicine, tissue engineering, renewable energy, environmental science, nanotechnology and material science, to name only a few fields. In all these applications, the final function depends on: (i) the specific mechanisms of protein aggregation, (ii) the hierarchical structure of the protein and peptide amyloids from the atomistic to mesoscopic length scales and (iii) the physical properties of the amyloids in the context of their surrounding environment (biological or artificial). In this review, we will discuss recent progress made in the field of functional and artificial amyloids and highlight connections between protein/peptide folding, unfolding and aggregation mechanisms, with the resulting amyloid structure and functionality. We also highlight current advances in the design and synthesis of amyloid-based biological and functional materials and identify new potential fields in which amyloid-based structures promise new breakthroughs.

595 citations

Journal ArticleDOI
TL;DR: A recent review as discussed by the authors describes recent advances in the stabilization of emulsions and foams by edible particles of nanoscale and micro-scale dimensions, including common food proteins such as whey protein, soy protein and gelatin.

326 citations

Journal ArticleDOI
TL;DR: A critical assessment of the characteristics of colloidal particles that impact the effectiveness of protein delivery systems, such as particle composition, size, permeability, interfacial properties, and stability are provided.

262 citations


Cites background from "The self-assembly, aggregation and ..."

  • ...Proteins may exist as individual molecules, small clusters, or large aggregates depending on solution conditions, such as pH, ionic strength, and temperature [18,19]....

    [...]

Journal ArticleDOI
TL;DR: The biological fate and the potential toxicity mechanisms of food amyloid fibrils are discussed, and an experimental protocol for their health safety validation is proposed in the concluding part of the review.

238 citations

References
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Book
01 Jan 1985
TL;DR: The forces between atoms and molecules are discussed in detail in this article, including the van der Waals forces between surfaces, and the forces between particles and surfaces, as well as their interactions with other forces.
Abstract: The Forces between Atoms and Molecules. Principles and Concepts. Historical Perspective. Some Thermodynamic Aspects of Intermolecular Forces. Strong Intermolecular Forces: Covalent and Coulomb Interactions. Interactions Involving Polar Molecules. Interactions Involving the Polarization of Molecules. van der Waals Forces. Repulsive Forces, Total Intermolecular Pair Potentials, and Liquid Structure. Special Interactions. Hydrogen-Bonding, Hydrophobic, and Hydrophilic Interactions. The Forces between Particles and Surfaces. Some Unifying Concepts in Intermolecular and Interparticle Forces. Contrasts between Intermolecular, Interparticle, and Intersurface Forces. van der Waals Forces between Surfaces. Electrostatic Forces between Surfaces in Liquids. Solvation, Structural and Hydration Forces. Steric and Fluctuation Forces. Adhesion. Fluid-Like Structures and Self-Assembling Systems. Micelles, Bilayers, and Biological Membranes. Thermodynamic Principles of Self-Assembly. Aggregation of Amphiphilic Molecules into Micelles, Bilayers, Vesicles, and Biological Membranes. The Interactions between Lipid Bilayers and Biological Membranes. References. Index.

18,048 citations

Journal ArticleDOI
19 Jul 2002-Science
TL;DR: It has been more than 10 years since it was first proposed that the neurodegeneration in Alzheimer's disease (AD) may be caused by deposition of amyloid β-peptide in plaques in brain tissue and the rest of the disease process is proposed to result from an imbalance between Aβ production and Aβ clearance.
Abstract: It has been more than 10 years since it was first proposed that the neurodegeneration in Alzheimer9s disease (AD) may be caused by deposition of amyloid β-peptide (Aβ) in plaques in brain tissue. According to the amyloid hypothesis, accumulation of Aβ in the brain is the primary influence driving AD pathogenesis. The rest of the disease process, including formation of neurofibrillary tangles containing tau protein, is proposed to result from an imbalance between Aβ production and Aβ clearance.

12,652 citations

Book
01 Jan 1992
TL;DR: In this article, a scaling solution for the Bethe lattice is proposed for cluster numbers and a scaling assumption for cluster number scaling assumptions for cluster radius and fractal dimension is proposed.
Abstract: Preface to the Second Edition Preface to the First Edition Introduction: Forest Fires, Fractal Oil Fields, and Diffusion What is percolation? Forest fires Oil fields and fractals Diffusion in disordered media Coming attractions Further reading Cluster Numbers The truth about percolation Exact solution in one dimension Small clusters and animals in d dimensions Exact solution for the Bethe lattice Towards a scaling solution for cluster numbers Scaling assumptions for cluster numbers Numerical tests Cluster numbers away from Pc Further reading Cluster Structure Is the cluster perimeter a real perimeter? Cluster radius and fractal dimension Another view on scaling The infinite cluster at the threshold Further reading Finite-size Scaling and the Renormalization Group Finite-size scaling Small cell renormalization Scaling revisited Large cell and Monte Carlo renormalization Connection to geometry Further reading Conductivity and Related Properties Conductivity of random resistor networks Internal structure of the infinite cluster Multitude of fractal dimensions on the incipient infinite cluster Multifractals Fractal models Renormalization group for internal cluster structure Continuum percolation, Swiss-cheese models and broad distributions Elastic networks Further reading Walks, Dynamics and Quantum Effects Ants in the labyrinth Probability distributions Fractons and superlocalization Hulls and external accessible perimeters Diffusion fronts Invasion percolation Further reading Application to Thermal Phase Transitions Statistical physics and the Ising model Dilute magnets at low temperatures History of droplet descriptions for fluids Droplet definition for the Ising model in zero field The trouble with Kertesz Applications Dilute magnets at finite temperatures Spin glasses Further reading Summary Numerical Techniques

7,349 citations

Journal ArticleDOI
Lars Onsager1
TL;DR: In this article, it was shown that colloids in general are apt to exhibit considerable deviations from Raoult's law and that crystalline phases retaining a fair proportion of solvent may separate from concentrated solutions.
Abstract: Introdzution. The shapes of colloidal particles are often reasonably compact, so that no diameter greatly exceeds the cube root of the volume of the particle. On the other hand, we know many coiloids whose particles are greatly extended into sheets (bentonite), rods (tobacco virus), or flexible chains (myosin, various Iinear polymers). In some instances, a t least, solutions of such highly anisometric particles are known to exhibit remarkably great deviations from Raoult’s law, even to the extent that an anisotropic phase may separate from a solution in which the particles themselves occupy but one or two per cent of the total volume (tobacco virus, bentonite). We shall show in what follows how such results may arise from electrostatic repulsion between highly anisometric particles. Most colloids in aqueous solution owe their stability more or less to electric charges, so that each particle will repel others before they come into actual contact, and effectively claim for itself a greater volume than what it actuaily occupies. Thus, we can understand that colloids in general are apt to exhibit considerable deviations from Raoult’s law and that crystalline phases retaining a fair proportion of solvent may separate from concentrated solutions. However, if we tentatively increase the known size of the particles by the known range of the electric forces and multiply the resulting volume by four in order to compute the effective van der Waal’s co-volume, we have not nearly enough to explain why a solution of 2 per cent tobacco virus in 0.005 normal NaCZ forms two phases.

4,260 citations

Journal ArticleDOI
TL;DR: It is hypothesized that impaired synaptic plasticity and associated memory dysfunction during early stage Alzheimer's disease and severe cellular degeneration and dementia during end stage could be caused by the biphasic impact of Abeta-derived diffusible ligands acting upon particular neural signal transduction pathways.
Abstract: Aβ1–42 is a self-associating peptide whose neurotoxic derivatives are thought to play a role in Alzheimer’s pathogenesis. Neurotoxicity of amyloid β protein (Aβ) has been attributed to its fibrillar forms, but experiments presented here characterize neurotoxins that assemble when fibril formation is inhibited. These neurotoxins comprise small diffusible Aβ oligomers (referred to as ADDLs, for Aβ-derived diffusible ligands), which were found to kill mature neurons in organotypic central nervous system cultures at nanomolar concentrations. At cell surfaces, ADDLs bound to trypsin-sensitive sites and surface-derived tryptic peptides blocked binding and afforded neuroprotection. Germ-line knockout of Fyn, a protein tyrosine kinase linked to apoptosis and elevated in Alzheimer’s disease, also was neuroprotective. Remarkably, neurological dysfunction evoked by ADDLs occurred well in advance of cellular degeneration. Without lag, and despite retention of evoked action potentials, ADDLs inhibited hippocampal long-term potentiation, indicating an immediate impact on signal transduction. We hypothesize that impaired synaptic plasticity and associated memory dysfunction during early stage Alzheimer’s disease and severe cellular degeneration and dementia during end stage could be caused by the biphasic impact of Aβ-derived diffusible ligands acting upon particular neural signal transduction pathways.

3,608 citations