Thermally triggered self-assembly of κ-casein amyloid nanofibrils and their nanomechanical properties

Lee, Ju-Bong; Lee, Ji Hye; Paik, Seung R.; Yeom, Bongjun; Char, Kookheon

doi:10.1016/j.polymer.2019.121626

Cited by 13 publications

(5 citation statements)

References 93 publications

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“…Fibril formation has been demonstrated for native and reduced forms of κ-CN (Farrell et al, 2003;Thorn et al, 2005Thorn et al, , 2008Lee et al, 2019), α S2 -CN (Thorn et al, 2008), and, to some degree, β-CN, although not under physiological conditions (Pan and Zhong, 2015). Fibril formation could not be induced for α S1 -CN (Thorn et al, 2008).…”

Section: Casein Fibrilsmentioning

confidence: 98%

Mechanisms of structure formation underlying the creaming reaction in a processed cheese model system as revealed by light and transmission electron microscopy

Vollmer

Kieferle

Youssef

et al. 2021

Journal of Dairy Science

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The "creaming reaction," a general thickening of the molten cheese mass during the manufacture of processed cheese, which is often seen to occur in a stepwise fashion, affects the viscosity and texture of the finished product. Thus, this phenomenon is of critical importance for the processed cheese industry, yet mechanisms underlying the structure formation in this surprisingly complex and dynamic food system are only poorly understood. Using a model system consisting of micellar casein concentrate, vegetable oil, water, and a mixture of melting salts, we followed the characteristic viscosity profile with its primary and secondary increase over time. A rheometer equipped with a custom-made cup geometry was used, which served as a mini-reaction vessel to simulate the conditions during the manufacture of processed cheese. The mixture was subjected to constant heat (90°C) and stirring (7.93 rpm), comparable to processed cheese cooking, for up to 410 min. At specific time points, samples were taken, and the micro-and ultrastructure was investigated with light and transmission electron microscopy. Results from our extensive study uncovered the following key steps: (1) a decrease in fat globule size with concomitant increase in the number of fat globules, which were also more evenly distributed; (2) a progressive separation of the casein matrix into fibrillogenic and nonfibrillogenic fractions; (3) formation of fibrils and their higher-order structuring followed by their partial degradation; and (4) increasing interactions of the fibrils with the fat globule surface leading to a higher degree of emulsification. Of these different observations, results indicate that after the caseins dissociated under the influence of the melting salts, protein-protein interactions were the primary driver of the structure formation and thus contributed to the initial viscosity increase. Fat globules were involved in the structure formation at later time points. Therefore, fat-protein interactions in addition to continued protein-protein interactions were assumed to contribute to the secondary viscosity increase. An updated processed cheese creaming model is presented. The use of the term "texturization" instead of "creaming" is proposed.

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Section: Casein Fibrilsmentioning

confidence: 98%

Mechanisms of structure formation underlying the creaming reaction in a processed cheese model system as revealed by light and transmission electron microscopy

Vollmer

Kieferle

Youssef

et al. 2021

Journal of Dairy Science

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“… 48 Denatured proteins that are prone to form amyloid structures can self-assemble into short, worm-like flexible nanofibril, followed by development into longer, semiflexible nanofibril. The polymorphism is observed in amyloidogenic proteins such as β-conglycinin in soy protein isolates, 85 β-lactoglobulin, 59 , 109 and κ-casein 141 in bovine milk, and ovalbumin from egg white. 124 Young’s modulus is higher for straight fibers compared to curved ones.…”

Section: Properties and Applicationsmentioning

confidence: 99%

From Fundamental Amyloid Protein Self-Assembly to Development of Bioplastics

Li,

Kambanis,

Sorenson

et al. 2023

Biomacromolecules

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Proteins can self-assemble into a range of nanostructures as a result of molecular interactions. Amyloid nanofibrils, as one of them, were first discovered with regard to the relevance of neurodegenerative diseases but now have been exploited as building blocks to generate multiscale materials with designed functions for versatile applications. This review interconnects the mechanism of amyloid fibrillation, the current approaches to synthesizing amyloid protein-based materials, and the application in bioplastic development. We focus on the fundamental structures of self-assembled amyloid fibrils and how external factors can affect protein aggregation to optimize the process. Protein self-assembly is essentially the autonomous congregation of smaller protein units into larger, organized structures. Since the properties of the self-assembly can be manipulated by changing intrinsic factors and external conditions, protein self-assembly serves as an excellent building block for bioplastic development. Building on these principles, general processing methods and pathways from raw protein sources to mature state materials are proposed, providing a guide for the development of large-scale production. Additionally, this review discusses the diverse properties of protein-based amyloid nanofibrils and how they can be utilized as bioplastics. The economic feasibility of the protein bioplastics is also compared to conventional plastics in large-scale production scenarios, supporting their potential as sustainable bioplastics for future applications. P lastics are now found in every sector of our life, such as packaging, personal care products, electronics, and clothing, while the contamination caused by the accumulation of single-use plastic 1−5 and microplastics 6,7 has become a serious threat to the natural environment, wildlife, and humans. Current plastics can be classified based on their source and their biodegradability, as shown in Figure 1. 8 Some plastics are

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“…We observed fibrillar objects in all samples. The morphology of the fibrils was similar to amyloids formed from β-lactoglobulin (Bolisetty et al ., 2011) and α-lactalbumin (Antosova et al ., 2019) but different than for κ-casein amyloids (Lee et al ., 2019). The objects found in samples of milk 1 and 2 were 0.5–2.5 μm long and 5–7 nm high.…”

Section: Resultsmentioning

confidence: 99%

Fibrillar aggregates in powdered milk

Wawer

Andrukajtis

Karczewski

et al. 2023

Journal of Dairy Research

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This research paper addresses the hypothesis that powdered milk may contain amyloid fibrils. Amyloids are fibrillar aggregates of proteins. Up to this time, research on the presence of amyloids in food products are scarce. To check the hypothesis we performed thioflavin T fluorescence assay, X-ray powder diffraction, atomic force microscopy and fluorescence microscopy imaging. Our preliminary results show that commercially available milks contain fibrils that have features characteristic to amyloids. The obtained results can be interpreted in two opposite ways. The presence of amyloids could be considered as a hazard due to the fact that food products may induce amyloid related diseases. On the other hand, the presence of amyloids in traditionally consumed foodstuffs could serve as proof that fibrils of food proteins do not pose a threat for consumers.

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Thermally triggered self-assembly of κ-casein amyloid nanofibrils and their nanomechanical properties

Cited by 13 publications

References 93 publications

Mechanisms of structure formation underlying the creaming reaction in a processed cheese model system as revealed by light and transmission electron microscopy

Mechanisms of structure formation underlying the creaming reaction in a processed cheese model system as revealed by light and transmission electron microscopy

From Fundamental Amyloid Protein Self-Assembly to Development of Bioplastics

Fibrillar aggregates in powdered milk

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