Gelling properties of surimi as affected by the particle size of fish bone

- Physicochemical properties of surimi incorporated with fish bone were affected by the particle size of fish bone.
- Nano-scaled bone (NFB) effectively improved gel texture while micro-scaled bone (MFB) did not.
- NFB particle was imbedded into the gel without disrupting the myofibrillar protein's networks.
- NFB significantly increased endogenous TGase activity of surimi due to possibly high calcium ions.
- NFB can be utilized to improve surimi gel texture while providing additional dietary calcium.

The effects of adding fish bone with two different particle sizes (micro and nano) on Alaska pollock surimi gels prepared by two heating procedures were investigated. Heating procedures (with or without setting) resulted in significantly different gel texture values. The addition of nano-scaled fish bone (NFB) (up to 1 g/100 g) effectively increased gel breaking force and penetration distance while micro-scaled fish bone (MFB) did not. Endogenous transglutaminase (TGase) activity of surimi paste increased obviously as the concentration of NFB increased, indicating calcium ions readily released from NFB and assisting gel formation through TGase-induced covalent bonds. With MFB, TGase activity increased slightly, but not significantly. Scanning electron microscopy (SEM) results revealed NFB was capable of being imbedded in the gel matrices without disrupting the myofibrillar gel network. Surimi with MFB formed a discontinuous and porous network with pores near the size of MFB. Lightness (L*) and whiteness (L*-3b*) of NFB gels were higher than those of MFB.