Effects of Hydrogel-to-Oleogel Ratio and Potato Protein Isolate Concentration on the 3D Printing and Post-Heating Properties of Food-Grade Bigels.

This study investigated the effects of the hydrogel-to-oleogel ratio and potato protein isolate (PPI) concentration on the printing and post-heating properties of food-grade bigels. Bigels with hydrogel-to-oleogel ratios of 10:0, 7:3, 5:5, 3:7, and 0:10 were evaluated for physical stability, rheological behavior, structural recovery, and 3D printing performance. Among the biphasic formulations, H7O3 exhibited the highest liquid-binding capacity (99.43%) and structural recovery ratio (88.7%) and produced lateral dimensions closest to those of the CAD model. H7O3 was therefore selected for PPI incorporation at 0-10 wt%. PPI incorporation improved the initial dimensional fidelity of the printed constructs and reduced rheological softening during heating. After heating at 120°C for 10 min, the 0% PPI construct collapsed, whereas all PPI-containing constructs retained identifiable three-dimensional shapes. Post-heating lateral deformation decreased with increasing PPI concentration, and the 10% PPI formulation exhibited width and length retention values closest to 100%. In addition, the 7 and 10% PPI formulations showed significantly lower cooking loss than the 3 and 5% formulations. These findings demonstrate that the hydrogel-to-oleogel ratio established the printing characteristics of the bigels, whereas PPI concentration modulated their initial dimensional fidelity and post-heating stability. The developed bigels have potential as 3D-printable structured lipid systems for fat-replacement applications.