The effect of cross‐linking degree on physicochemical properties of surimi gel as affected by MTGase

• Published in: Journal of the science of food and agriculture 2021-12, Vol.101 (15), p.6228-6238
• Main Authors: An, Yueqi, Xiong, Shanbai, Liu, Ru, You, Juan, Yin, Tao, Hu, Yang
• Format: Article
• Language: English
• Subjects: Brittleness; Combined water; Diameters; Embrittlement; Fractal geometry; Gels; Hydrophobicity; Links; Microenvironments; Microorganisms; network structure; Physicochemical properties; Proteins; Raman spectrum; Surimi; surimi gel; Texture; TGase‐induced cross‐linking degree
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.11274

BACKGROUND The transglutaminase‐induced cross‐linking reaction can enhance the textural properties of surimi gels. However, when the cross‐linking degree exceeds a certain range, surimi gels become brittle, giving the gel a special mouthfeel. Little information is to be found regarding the brittleness of surimi gel and its formation mechanism. The present study aimed to investigate the effects of cross‐links on physicochemical properties of surimi gel and to analyze the reason for the textural variation of surimi gels regulated by cross‐links. RESULTS When the cross‐linking degree was lower than about 30%, the surimi gel could not be fractured and the surimi gel was mushy. When the cross‐linking degree was around 40–55%, surimi gels without microbial transglutaminase (MTGase) presented an elastic texture, while surimi gels with MTGase displayed a tough texture. When the cross‐linking degrees were 64.1% and 76.5%, surimi gels became brittle. Water holding capacity decreased with the increase in cross‐linking degree and the cross‐links released some combined water to free water. With the increase in cross‐links, the pore equivalent diameter and the fractal dimension first decreased and then increased. When the cross‐linking degree exceeded approximately 50%, hydrophobic interaction increased, consistent with the exposure of hydrophobic residues and the decrease in the water gap between proteins. CONCLUSION The changes in gel texture were related to micro‐network structure, water status and microenvironment of proteins. It was demonstrated that the texture of slowly heated surimi‐based products could be regulated by controlling the TGase‐induced cross‐links. © 2021 Society of Chemical Industry.