The aggregation of proteins is central to many aspects of daily life, including food processing, blood coagulation, eye cataract formation disease and prion-related neurodegenerative infections [1][2][3][4][5] . However, the physical mechanisms responsible for amyloidosis-the irreversible fibril formation of various proteins that is linked to disorders such as Alzheimer's, Creutzfeldt-Jakob and Huntington's diseases-have not yet been fully elucidated [6][7][8][9] . Here, we show that different stages of amyloid aggregation can be examined by performing a statistical polymer physics analysis of single-molecule atomic force microscopy images of heat-denatured b-lactoglobulin fibrils. The atomic force microscopy analysis, supported by theoretical arguments, reveals that the fibrils have a multistranded helical shape with twisted ribbon-like structures. Our results also indicate a possible general model for amyloid fibril assembly and illustrate the potential of this approach for investigating fibrillar systems.Protein self-assembly is a wide-ranging phenomenon and is of great importance in several areas of science. The reversible formation of fibrils from globular proteins is a phenomenon occurring naturally, in vivo, for proteins such as actin and tubulin 10,11 . Other well-known examples of protein fibrillation include the irreversible amyloid fibril formation of various proteins implicated in neurological disorders such as Alzheimer's, Creutzfeldt-Jakob or Huntington's diseases. Typically, these fibrils have long, unbranched, and often twisted structures that are a few nanometres in diameter 1,8 . However, many peptides and proteins, including many globular food proteins that are used as gelling agents, foaming agents or emulsifiers, can also form amyloid-like structures in vitro. Such structures can possess desirable mechanical properties and can be used to create useful textures and structures 12,13 .An example of a fibril formation of globular proteins is provided by the fine-stranded heat-set gels formed by heating solutions of various globular food proteins such as ovalbumin, bovine serum albumin 12 and b-lactoglobulin 13 . b-Lactoglobulin has been particularly well studied, because it represents both a relevant model system and a major whey protein of interest to the food industry [14][15][16][17][18][19][20][21][22] .Despite the fact that the individual parameters controlling the aggregation of globular proteins into amyloid fibrils have been well identified, the driving force for such an aggregation process still remains obscure. Studies devoted to the characterization of fibril structures based on light, neutrons and X-ray scattering methods, being bulk techniques, have only provided an average ensemble picture of the fibrils 23 . Single-molecule techniques such as atomic force microscopy (AFM) and transmission electron microscopy (TEM) have recently emerged to probe amyloid fibrils at the molecular level [24][25][26][27] . Nevertheless, so far, a fully comprehensive picture of the aggregation behaviour...

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.

Foods make up some of the most complex examples of soft condensed matter (SCM) with which we interact daily. Their complexity arises from several factors: the intricacy of components, the different aggregation states in which foods are encountered, and the multitude of relevant characteristic time and length scales. Because foodstuffs are governed by the rules of SCM physics but with all the complications related to real systems, the experimental and theoretical approaches of SCM physics have deepened our comprehension of their nature and behaviour, but many questions remain. In this review we discuss the current understanding of food science, by considering established SCM methods as well as emerging techniques and theoretical approaches. With their complexity, heterogeneity and multitude of states, foods provide SCM physics with a challenge of remarkable importance.

We review and analyze current water purification technologies in the context of sustainability, and we introduce the Ranking Efficiency Product (REP) index, to evaluate their efficiency and implementation in this broader perspective.