Food-derived protein fibril-based multiscale structured systems: Construction, potential applications, and future prospects

Structured systems constructed from self-assembled proteins have garnered considerable interest because of their biocompatibility, sustainability, design flexibility, and diverse potential applications. Natural proteins derived from animals, plants, and microorganisms can self-assemble into structurally and functionally enhanced supramolecules under specific conditions. By leveraging their interfacial and gel properties, these self-assembled proteins can create multifunctional structured systems at varying micro- and macro-scales, spanning from nano- to micron-level dimensions. This can be achieved through engineering design or polymer composite hybridization, resulting in bioactive materials such as carrier templates, emulsification templates, microcapsules, micro/nano-gels, block gels, aerogels, films, fibers, and so on [1]. Their application across numerous disciplines, including drug/nutritional delivery, disease treatment, meat tissue simulation, biological tissue scaffolds, food packaging, and filtration/purification, has significantly advanced biomedicine, the food and pharmaceutical industries, and materials science.

Protein fibrils (PFs) generated through self-assembly exhibit remarkable flexibility in the pathways of structural foundation, functional buildup, and divergent design, typically implemented in artificial settings using bottom-up strategies. Their superior one-dimensional structure, characterized by a high aspect ratio, anisotropy, ordered assembly, high mechanical stiffness, controllability, desirable stability, and surface activity, rivals that of naturally occurring self-assembled biomaterials like spider silk protein fibers. Therefore, PFs are promising candidates for serving as supramolecular building blocks in structured systems [2]. Additionally, their advantageous interfacial properties facilitate PFs migration to various interfaces, such as oil-water, water-water, and water-air interfaces, enabling arrangement, stacking, and structuring at the two-dimensional level. Inspired by natural organisms, PFs nanostructure units are used to construct more complex three-dimensional structures by manipulating external factors, such as environmental conditions, artificial stimuli, constraints, or orientations, and blocking/fixing them through gel behavior [1]. Although there are currently only a few examples of PFs-based basic structured systems, the proliferation of research and applications is expected to increase significantly due to growing practical demands across various industries and advancements in intelligent technologies.

Food proteins, renowned for their biocompatibility, biodegradability, and nutritional advantages, exhibit versatility in food innovation, functional ingredient development, bioengineering applications, and drug delivery systems. Additionally, the utilization of food proteins aligns with the escalating demand for sustainable materials in the biomedical sector, as they can be sourced from food industry by-products, thereby minimizing waste and fostering a circular economy. Various food proteins, such as milk, egg, and soy proteins, have been shown to convert readily into PFs in vitro under appropriately designed conditions, often involving heating at low pH and decreased salt concentrations [3], [4]. Although amyloid structure were initially linked to human diseases, the ubiquitous presence of functional food-derived PFs in nature, coupled with their favorable biophysical properties, has sparked interest in exploring their potential applications across various fields, and a multitude of promising and successful applications has already been validated [3], [5], [6], [7], [8]. To achieve a comprehensive understanding of food protein-derived PFs and their applications, thus, this work systematically conducted a comprehensive analysis of food protein-derived PFs, progressing from an examination of their structural features to their functional capabilities, transitioning from lower-dimensional to higher-dimensional considerations, and moving from the exploration of underlying mechanisms to the development of practical applications. This review highlights the unique attributes, advantages, and potentials of food protein-derived PFs development across various disciplines, with the ultimate goal of stimulating and enhancing the progression and utilization of PFs-based structured systems.