Modulation of oligoguluronate on the microstructure and properties of Ca-dependent soy protein gels.

Naturally-sourced oligoguluronate (GB) has Ca-binding ability and can be employed to modulate Ca-dependent gels. Here soy protein isolate (SPI) gel was used as a model to investigate the influence of GB on the microstructure and properties of Ca-dependent food gels. The results showed that GB significantly decreased the storage modulus (G'), mechanical strength, elasticity, hardness and chewiness of SPI gels. Among all samples, the gel containing 30 mM GB showed the most compact network structure and thus the highest water holding capacity of 77.5 %. It should be noted that Ca-GB dimers were beneficial to the gel formation and can modify the gel properties but have no impact on the gelation kinetics. The findings gained in this study confirmed the great potential of GB in modulating the structure and properties of Ca-dependent gels, thereby obtaining food products with desired characteristics (e.g., soft and brittle tofu).