Soybean meal protein, a byproduct of soybean processing, has limited functional properties such as emulsifying performance, which restricts its application in foods. Given that high-temperature extrusion tends to cause excessive denaturation and irreversible aggregation, this study aimed to investigate the effects of relatively low extrusion temperatures (85–105 °C) on the structural and functional properties of soybean meal protein. The results showed that extrusion altered the molecular structure and functional characteristics of the protein. With increasing extrusion temperature, the β-sheet content increased while the α-helix content decreased in the secondary structure, and tertiary structural rearrangements occurred, with hydrophobic groups being exposed and subsequently buried. At 95 °C, the protein formed a relatively porous and loose microstructure and exhibited the strongest surface hydrophobicity, water-holding capacity, oil-holding capacity, and emulsifying properties; at 100 °C and above, excessive aggregation occurred, pore structure collapsed, and functional properties declined. Meanwhile, extrusion generally reduced protein solubility. Therefore, 95 °C is identified as the optimal extrusion temperature under the conditions of this study. In addition, this study reveals the correlation between structural reconstruction and functional changes of soybean meal protein, providing a theoretical basis for its high-value utilization and application in the food industry.
Rong Ma, Xi-Qin Pan, Yu-Han Zhuang et al.· Foods· 0 citations
This study investigated the synergistic effects of supercritical carbon dioxide (SCCD) combined with sucrose treatment on the foaming properties and freeze-thaw stability of egg white protein (EWP). The results demonstrated that SCCD-sucrose treatment significantly enhanced the foaming capacity, achieving a maximum of 139.5% (4.6-fold increase over the control) at 9 MPa for 60 min with 10 g/100 mL sucrose, while maintaining the foaming stability (FS) which was compromised by SCCD treatment alone. Furthermore, the treated EWP exhibited markedly improved stability against repeated freeze-thaw cycles. Mechanism analysis revealed that sucrose promoted the formation of larger protein aggregates, as evidenced by increased particle size, and significantly reduced surface tension, enhancing adsorption at the air-water interface. Fourier transform infrared spectroscopy indicated a rise in α-helix relative content, contributing to structural ordering, while rheological measurements showed improved elastic modulus (G′), supporting FS. Scanning electron microscopy further revealed a more cohesive and dense protein network of SCCD-sucrose treated group. These synergistic modifications counteracted the structural loosening induced by SCCD and facilitated the formation of a robust interfacial film. The findings provide an effective and promising physical modification strategy for enhancing the functional performance of frozen-stored egg white liquid in the egg processing industry.
Lixian Ding, Minquan Xia, Xinyue Zhang et al.· Food Science of Animal Produ...· 0 citations