Modulating water mobility in comminuted meat protein gels using model hydrophilic filler particles

Abstract

Glass microspheres (3–6 μm and 30–50 μm diameter) and diamond particulates (1–3 μm, 3–7 μm, and 30–50 μm diameter) were employed as model hydrophilic fillers in comminuted poultry meat protein gels to evaluate the contribution of surface characteristics. The irregular surface morphology and more mild hydrophilic nature of the diamonds contrasted with the high sphericity and strong hydrophilicity of the glass microspheres. For comminuted meat protein gels prepared with both low and high protein content (9.5% and 10.2%), substantial liquid expulsion was observed in the absence of filler. The 3–6 μm glass fillers enhanced the large deformation and recovery properties of the low protein gels, while both protein levels displayed a significant reduction in thermally-induced liquid expulsion. The diamond particles had no significant impact on liquid retention or gel strength at either protein level; however, the smaller particulates decreased the recoverable energy of the high protein composite gels. Light microscopy and T2 relaxometry support the hypothesis that the 3–6 μm glass microspheres reduce water mobility by supporting water-filled capillary channels within the gel network. In contrast, the diamond particles are unable to immobilize the aqueous phase by this mechanism due to their weaker hydrophilic nature and irregular surface morphology.