Oil distribution and stability modulate textured vegetable protein hydration and juiciness perception in plant-based meat analogues

Abstract

Juiciness remains one of the key challenges in developing plant-based meat analogues (PBMAs). In this study, oil-in-water (O/W) emulsions with varying oil droplet size distributions (∼ 4 to ∼ 114 μm) were incorporated into PBMA systems to enhance oil distribution and retention during cooking. Sensory evaluation, compression loss analysis, microscopy, micro-CT, and mathematical modelling were employed to assess these effects. Our results indicated that overall oil droplet stability played a more critical role than droplet size distribution. PBMAs formulated with lecithin-stabilized emulsions showed significantly lower cooking loss and higher initial juiciness scores compared with those containing an unstabilized water-oil mixture without lecithin (E_water-oil, 77.5 vs. 52.5, p < 0.05). However, further refining the droplet size range from 26 to 4 μm had a limited impact on overall juiciness perception. Modelling of water and oil sorption in textured vegetable protein (TVP) using parallel exponential kinetics (PEK) further supported these findings. A strong positive correlation was observed between bound water absorption and the initial fast sorption phase. This relationship explains the higher cooking loss observed in the TVP-E_water-oil system, where the unstable oil phase with irregular distribution disrupted bound water binding. Consequently, more free water and adsorbed oil accumulated in regions with lower water-binding capacity. In contrast, stabilized emulsions formed a more uniform coating of oil droplets around the TVP, interfering less with bound water hydration during the initial sorption process, which contributed to better water retention and higher juiciness scores. These findings provide valuable insights for optimizing oil distribution in PBMA formulations and offer practical strategies to enhance juiciness perception in PBMAs.