Fish skin collagen improves ostrich myofibrillar protein heat-set gels through hydrophobic interaction-driven network formation

This study developed a fish skin collagen (FSC) and ostrich myofibrillar protein (OMP) composite system to investigate how FSC affects the gel properties of OMP when heated. The analysis focused on structural and gel-related properties, including solubility, particle size, surface hydrophobicity, and water-holding capacity. Results indicated that adding 0–0.75% FSC formed soluble aggregates with OMP through hydrogen bonding and hydrophobic interactions, which reduced OMP's disordered self-aggregation during heating. At 0.75% FSC, the composite gel formed the most compact and continuous three-dimensional network, as evidenced by microstructural imaging and corroborated by the maximum hydrophobic-interaction contribution, the strongest network elasticity, and the highest cooking yield and water-holding capacity. Compared to the control, cooking yield and water-holding capacity rose by 16.71% and 25.96%, respectively, with notable improvements in hardness, elasticity, and chewability. Mechanistic analysis showed that hydrophobic interactions mainly drove gel network formation, while hydrogen bonds enhanced water retention and stability. However, adding 1% FSC led to excessive aggregation, disrupting network continuity and gel properties. Thus, 0.75% FSC was optimal for enhancing OMP gel properties within the 0–1.0% addition range. These findings offer valuable insights and guidance for high-value processing of ostrich meat.