Fibrillation of soy protein isolate in the presence of metal ions: Structure and gelation behavior

• Published in: Food chemistry 2024-09, Vol.453, p.139672-139672, Article 139672
• Main Authors: Zhao, Hekai, Xu, Xinru, Yuan, Bingbing, Qi, Baokun, Li, Yang
• Format: Article
• Language: English
• Subjects: Fibrillation; Gelation; Metal ion; Soy protein isolate fibril
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2024.139672

The structure and functional properties of protein fibrils are closely related to environmental factors in fibrillation. Herein, soy protein isolate fibrils (SPIFs, 22 mg/mL) were prepared under acid-heating conditions in the presence of 100 mM metal ions (K+, Na+, Ca2+, Mg2+, and Fe3+). Except for Fe3+, fibrillation and subsequent larger fibril aggregates were promoted, ultimately leading to gel formation. Compared with K+ or Na+, the addition of Ca2+ or Mg2+ resulted in more organized SPIF structures with increased β-sheet contents and higher ThT fluorescence intensities. Furthermore, both of them resulted in longer fibrils with an average contour length of 700–800 nm, which significantly enhanced the storage modulus. However, the presence of Fe3+ accelerated protein hydrolysis and inhibited SPIF formation, resulting in samples consistently exhibited liquid behavior. These findings provide a foundation for understanding the influence of metal ions on regulating the fibrillation and gelling properties of SPIFs. [Display omitted] •Metal ions can modulate the morphology and gel properties of SPIF.•The presence of Ca2+ and Mg2+ facilitated the formation of elongated SPIF structures.•Fe3+ inhibited the formation of SPIF but accelerate the rate of hydrolysis.•The formation of fibrils enhanced the gel properties of SPI.