Computational Design of Fat Marbling Formation in Plant-Based Meat: Coupled CFD and Image Analysis of Oil Transport During Co-Extrusion

초록

Featured Application The integrated rheology, thermal transition, imaging, and computational fluid dynamics (CFD) framework developed in this study can be applied to design and scale cooling-die temperature profiles, residence times, and oil injection conditions for co-extrusion of plant-based meat analogs, supporting more consistent control of fat marbling distribution, texture development, and product-to-product consistency in industrial production lines. This study developed and evaluated an integrated experimental-computational framework to quantify coconut-oil transport and marbling stabilization in soy protein concentrate (SPC) during static holding and co-extrusion with a cooling die. Temperature-sweep rheology and Differential Scanning Calorimetry (DSC) identified the main gelation transition at 65-78 degrees C, with oil shifting gelation to higher temperatures and increasing enthalpy, supporting an exit/cooling target of 70-75 degrees C. Static drop tests at 100 degrees C for 60 s were analyzed by depth-resolved imaging and coupled with a single-phase CFD model to inversely calibrate an effective diffusion coefficient for coconut oil in SPC (D-ref = 4.86 x 10(-18) m(2)/s). A viscosity-coupled fractional Stokes-Einstein relationship then gave temperature-dependent effective diffusivities of 1.89 x 10(-18) to 4.86 x 10(-18) m(2)/s over 60-100 degrees C, indicating reduced oil mobility during cooling. Additional static time-temperature comparisons suggested limited redistribution beyond similar to 50 s. Co-extrusion simulations and product imaging further indicated that staged hot-zone residence followed by rapid cooling can help stabilize oil domains into marbling-like structures. The framework can support selection of cooling-die temperatures, residence times, and oil-injection conditions. Future work should extend the framework by linking marbling microstructure with sensory performance, oxidative stability, and sensitivity analysis of key transport parameters.

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