Mechanism study on egg yolk addition improving the gel properties of low-salt chicken breast paste

Abstract This study investigated the improvement of gel properties in low-salt chicken breast mince and its underlying mechanism by adding different proportions of egg yolk (EY). Results showed that adding 1.0% EY significantly improved the textural properties of the low-salt chicken breast mince, the hardness increased from 900 to 1 059 g, and the springiness rose from 0.88 to 0.95. Meanwhile, the cooking loss decreased from 12.3% to 9.02%, and the water-holding capacity (WHC) increased from 60.67% to 82.67%. The relaxation peaks of immobilized water (T22) and free water (T23) both shifted toward lower relaxation time, which resulted in a dense microstructure and enhanced WHC, comparable to the positive control group. Further extraction of myofibrillar protein (MP) revealed that 1.0% EY addition significantly increased particle size and surface hydrophobicity while reducing free sulfhydryl content, the particle size increased from 44.29 to 96.63 μm, the surface hydrophobicity rose from 151.9 to 164.20 μg, and the free sulfhydryl content decreased from 18.99 to 15.14 μmol/g, this was accompanied by a structural shift from α-helix to β-sheet and enhanced fluorescence intensity. Additionally, increased disulfide bond and hydrophobic interactions enhanced cross-linking between EY and MP. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and laser confocal analysis confirmed protein aggregation, forming a compact gel network structure. This study elucidates the improvement of EY on the gel properties of low-salt minced meat and its mechanism of action, providing a theoretical basis for its application in low-salt minced meat products.