Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand
Yellow stripe trevally (Selaroides leptolepis) is one of the abundant dark-fleshed fish species caught in Southern Thailand. However, the pelagic fish have high content of dark flesh associated with the high lipid and myoglobin contents contributing to the difficulties in making high-quality surimi. However, setting or heating at an appropriate temperature can improve the property of gel by avoiding the degradation but enhancing cross-linking of proteins. Therefore, the objective of this study was to investigate the gel-forming ability of surimi from yellow stripe trevally prepared under different heating conditions. Surimi gels were prepared under different heating conditions. Textural properties, whiteness, expressible moisture content, trichloroacetic acid (TCA)-soluble peptide content, protein pattern and microstructure of gels were determined. Additionally, the optimal temperature of muscle transglutaminase (TGase) was determined using monodansyl cadaverine incorporation method. Kamaboko gel with prior setting at 40°C (K40) exhibited the highest breaking force, followed by another kamaboko gel having setting temperature of 25°C, directly heated gel and modori gel, respectively (p < 0.05). For deformation, both kamaboko gels showed the lower values than both directly heated gel and modori gel (p < 0.05). The lowest expressible moisture content and whiteness were found in K40 sample (p < 0.05). The optimal temperature of yellow stripe trevally muscle transglutaminase was found to be 40°C. The highest TCA-soluble peptide content with decreased myosin heavy chain was found in modori surimi gel (p < 0.05). K40 sample had finer and more ordered fibrillar structure with smaller voids than other gels. Yellow stripe trevally could be used as the new raw material for surimi which yielded the gel with high deformation. Setting at 40°C is a promising means to improve the properties of surimi gel. Conversely, the incubation of sol at temperature close to 60°C should be avoided to prevent gel weakening.