Concentration-Regulated Fibrillation of Soy Protein: Structure and In Vitro Digestion

Abstract

The impact of protein types, heating temperatures, and times on protein fibrillation has been widely studied. However, there is little understanding of the influence of protein concentration (PC) on the protein fibril assembly. In this work, the structure and in vitro digestibility of soy protein amyloid fibrils (SAFs) were investigated at pH 2.0 and different PCs. Significant increases in fibril conversion rate and parallel β-sheets proportion were observed in SAFs upon increasing the PC from 2 to 8% (w/ v). The AFM images showed that curly fibrils were prone to form at 2−6% PCs, while rigid, straight fibrils developed at higher PCs (≥8%). As evidenced in XRD results, increasing PC led to a more stable structure of SAFs with enhanced thermal stability and lower digestibility. Moreover, positive correlations among PC, β-sheet content, persistence length, enthalpy, and total hydrolysis were established. These findings would provide valuable insights into concentration-regulated protein fibrillation.

Effect of dry‐ and moist‐heat treatment processes on the structure, solubility, and in vitro digestion of macadamia protein isolate

“…The crystal structure was influenced by the alteration in hydrogen bond content, yielding differing peak intensities. The peak at angles of approximately 9.1 • in the 2θ region was identified as the cross-β-sheet structure of amyloid fibrils in soy structure as well (Zheng et al, 2023). The prominence of the two peaks increased, possibly due to enhanced chain crosslinking, rendering the structure more orderly and stable (M. Hu et al, 2023).…”

Degree of Hydrolysis Regulated by Enzyme Mediation of Wheat Gluten Fibrillation: Structural Characterization and Analysis of the Mechanism of Action

“…WGP fibrillation was assessed by measuring ThT fluorescence intensity [29] based on previous studies showing that the enhancement of ThT fluorescence intensity indicates cross-β structure generation [18,24]. According to Figure 2, the ThT fluorescence intensity of DH4-8 WGPs increased to varying degrees from the beginning of the incubation at 0 h to the end of the incubation at 48 h. The WGPs of DH6 had the highest ThT fluorescence intensity after 36 h of incubation and was significantly higher than the other four DHs of the WGPs.…”

“…The large number of β-sheet structures contained in WG also provides a quantitative basis for the formation of cross-β structures [12,13]. There are many proteins that can form AFs, such as egg white lysozyme [14], β-Lactoglobulin [15,16], insulin [17], soy protein [18], rice protein [19], oat protein [20], etc. The key to the formation of AFs is unfolding, followed by self-assembly [1].…”