Effect of sweep frequency ultrasound and fixed frequency ultrasound thawing on gelling properties of myofibrillar protein from quick-frozen small yellow croaker and its possible mechanisms

Abstract The effects of sweep frequency ultrasound thawing (SFUT) and fixed frequency ultrasound thawing (FFUT) on the water holding capacity (WHC), strength, color, rheological properties as well as moisture migration and distribution of myofibrillar protein (MP) gel from small yellow croaker (Larimichthys polyactis) were evaluated. The results showed that the MP gel from the SFUT sample had a smaller chromatic aberration (ΔE) (12.39), higher WHC (65.05%) and strength (101.03 g) than the MP gel from FFUT and flow water thawing (FWT) samples. Compared with FFUT and FWT groups, the MP gel from the SFUT sample had higher elasticity and smaller apparent viscosity. Meanwhile, the MP gel from the SFUT sample had higher immobilized water content and lowered free water content close to the fresh sample (FS). Overall, the MP gel from the SFUT sample had better gelling properties than the MP gel from the FFUT and FWT groups.