Evaluation of rennet-induced gelation under different conditions as a potential method for 3D food printing of dairy-based high-protein formulations

The rennet-induced gelation of milk proteins was evaluated as a potential method for the formation of 3D printed food structures. The effects of pH, [Ca2+], and temperature on the rennet gelation properties of milk protein dispersion with 15% (w/w) protein content were assessed using low amplitude strain oscillation rheometry. A cycled-temperature ramp (heating-holding-cooling) during rheological measurements was suitable to evaluate gel firmness development, as an imitation of the temperature profile in the 3D printing process. A factorial design considering two levels of pH (6.0 and 6.4), [Ca2+] (1.5 and 5.7 mM), and temperature (31 and 40 °C), showed that the pH, temperature, and its interaction were the main factors enhancing gel formation and the strength of the resultant gel. At pH 6.0 and temperature ramped to 40 °C followed by cooling to 15 °C, a very high gel strength (~8–9 kPa) was obtained. These results showed that rennet-induced gelation could be manipulated for developing printable dairy formulations. [Display omitted] •High solubility of MPI was achieved using skim milk under high and low shear mixing.•Mimicking 3D printing temperature profile allowed early detection of rennet gelation.•pH and temperature were more significant than [Ca2+] for milk rennet gelation.