Modifying yellowfin tuna myofibrillar proteins under ultra-high pressure auxiliary heat treatment: Impact on the conformation, gel properties and digestive characteristics

Abstract

This study investigated the changes in physicochemical and functional properties of yellowfin tuna myofibrillar protein (MP) under various ultra-high pressure (UHP) auxiliary heat methods. The UHP-assisted heat treatment induced a rearrangement of the MP secondary structure, facilitating the formation of MP gel networks and resulting in higher storage modulus (G') values. Microstructure results revealed that MP gel produced with UHP auxiliary heat exhibited a more rigid network. As pressure increased, the regular aggregation of protein molecules enhanced the stability and water-binding capacity within the gel network, particularly under the two-stage UHP auxiliary heat (TUH) condition at 300 MPa. MP gel prepared under this condition exhibited a 1.95-fold increase in gel strength compared to the control group and the lowest creep strain. Furthermore, in vitro simulated digestion results indicated that TUH method significantly improved the digestive properties of MP gel, suggesting potential for the development of easily digestible MP-based gel foods.