Thermal Gel Degradation (Modori) in Sturgeon (Acipenseridae) Surimi Gels

Sturgeon meat has been found to be suitable as surimi raw materials. The present study determined the modori phenomenon in sturgeon surimi gels and identified its relationship with cathepsins. In all heat-treated gels (25 to 90 °C, at 5 °C intervals), the 40 °C-incubated sturgeon surimi gel showed the weakest gel properties and water-holding capacity (P < 0.05), a rough protein gel network under SEM, and the highest protein solubility and trichloroacetic acid-soluble peptides content (P < 0.05). SDS-PAGE indicated that the myosin heavy chain band of sturgeon surimi gels was almost completely degraded at 40 °C. Moreover, the highest cathepsin L activity was observed in 40 °C-treated sturgeon surimi gels (P < 0.05). Our results suggested that the modori phenomenon in sturgeon surimi gels occurred at 40 °C, which was partially attributed to cathepsin L, thereby allowing for the better exploitation and utilization of sturgeon surimi.