Structural, rheological and functional properties of extruded mozzarella cheese influenced by the properties of the renneted casein gels

Renneted casein gels, often named cheese curds, are traditionally pre-heated by immersion in water before stretching, which influences functional properties. This work aims to understand the effect of pre-heating (cooking) on extrusion process curds at 80 and 90 °C a lab twin-screw, co-rotating extruder, consequences for composition, microstructure properties extrudates. The cooking significantly enhanced curd meltability oiling-off, resulting faster extrusion, higher exit temperature lower specific mechanical energy. Microscopic observations different length scales, combining confocal laser scanning microscopy X-ray micro-tomography, showed that caused extensive fat coalescence cracks protein matrix, extrudates with less fibrous structure, elasticity tensile strength. induced increased calcium bridges extrudates, may replace weak water-protein interactions increase relaxation time more mobile fraction (T2.2). energy was influenced cooked than uncooked likely due oiling-off during curd. In agreement microscopic observations, obtained differ from specially regarding content respectively 23.8–24.8% 29.5% (w/w) globule size distribution, influencing fiber formation. general extruded had strength, related well-elongated domains. study provided knowledge about generating new ideas improve processing design customized products.