Improvement of low-acyl gellan gum on gelation and microstructural properties of protein hydrolysates from male gonad of scallop (Patinopecten yessoensis).

• Low-acyl gellan gum had effect on gelation of scallop male gonad hydrolysates (SMGHs). • Gel strength of SMGHs was increased with increasing of low-acyl gellan gum (GG) dose. • The thermal stability of SMGHs gel was improved by the addition of GG. • The promoting effect of GG on SMGHs gel was related to the water migration. • The SMGHs/GG composite gels showed a regular and homogenous network. This study aimed to examine the gelation and microstructural properties of scallop male gonad hydrolysates (SMGHs) in the presence of low-acyl gellan gum (GG) at different mass ratios. The rheological results showed that both elastic modulus and thermal stability of SMGHs were significantly improved by the addition of GG. Meanwhile, the relaxation time T 23 was significantly reduced in SMGHs/GG by low-field nuclear magnetic resonance, indicating a strong interaction between SMGHs and GG. Fourier transform infrared spectroscopy indicated the blueshift of amide I and II peaks in SMGHs/GG further demonstrated the electrostatic interaction between SMGHs and GG. The network structure of SMGHs/GG binary complexes was more compact and the surface was smoother than that of SMGHs by cryo-scanning electron microscopy. Furthermore, increasing the content of GG in the SMGHs/GG binary complex significantly reinforced the gel strength and promoted the gelation process. [ABSTRACT FROM AUTHOR]