Micrometer-Sized Fibrillar Protein Aggregates from Soy Glycinin and Soy Protein Isolate

Abstract

Long, fibrillar semiflexible aggregates were formed from soy glycinin and soy protein isolate (SPI) when heated at 85 degrees C and pH 2. Transmission electron microscopy analysis showed that the contour length of the fibrils was approximately 1 microm, the persistence length 2.3 microm, and the thickness a few nanometers. Fibrils formed from SPI were more branched than the fibrils of soy glycinin. Binding of the fluorescent dye Thioflavin T to the fibrils showed that beta-sheets were present in the fibrils. The presence of the fibrils resulted in an increase in viscosity and shear thinning behavior. Flow-induced birefringence measurements showed that the behavior of the fibrils under flow can be described by scaling relations derived for rodlike macromolecules. The fibril formation could be influenced by the protein concentration and heating time. Most properties of soy glycinin fibrils are comparable to beta-lactoglobulin fibrils.

Effect of heat-induced formation of rice bran protein fibrils on morphological structure and physicochemical properties in solutions and gels

“…7. Generally, the complete gel process consists of 2 stages, including a first stage of protein molecule denaturation, unfolding, and interactions, followed by a second of cooling (28). The mechanical moduli (G' and G'') of total protein (12.0 wt%) gels were measured using a strain sweep.…”

The Critical Aggregation Concentration of β-Lactoglobulin-Based Fibril Formation

“…They can be formed from various food proteins like egg white proteins [1][2][3][4][5] , soy proteins 6 , and whey proteins [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . The fibrils can, for example, be used as structurants and thickeners to give food products a specific texture.…”

Flow-assisted assembly of nanostructured protein microfibers

“…The formation of PNFs was initially observed in association with diseases, such as Alzheimer's and Parkinson's diseases, and type II diabetes, where human organs are impaired by fibrous protein inclusions referred to as amyloid (4). However, several non-disease-related proteins have also been shown to form amyloid-like fibrils, e.g., the bovine whey protein β-lactoglobulin (5), hen-egg lysozyme (6), and soybean proteins (7). The unique fibrous structures of PNFs have the potential for being the building block of protein-based nanomaterials and to be used as scaffolds for applications such as tissue engineering, drug delivery systems, and biosensors (3).…”