Influence of structural properties of textured vegetable proteins on in vitro gastric digestion kinetics of plant-based meat analogue patties

Summary

Textured vegetable proteins (TVPs) differ in structural properties that may affect the protein digestion of TVP-based meat analogues. This study explored the influence of structural properties on in vitro gastric protein digestion of TVPs and TVP-based patties. Eight TVPs differing in macroscopic surface area and microstructural properties (porosity, wall density, etc.) were used. As references, TVPs were ground into powders to remove their porous structure. In vitro gastric protein digestion was determined following the INFOGEST protocol. Structural properties were correlated with free amino group concentrations at different digestion times. For intact TVPs, surface area (r = 0.78) and mean pore size (r = 0.74) showed significant positive correlations with free amino group concentrations at 5 min of digestion. These correlations persisted for patties (at 30–120 min for surface area, 5–60 min for mean pore size). For TVP powders, wall density was the main structural feature, which was negatively correlated with free amino group concentrations at 5 min (r = −0.78) and 30 min (r = −0.91) of digestion. Wall density was not correlated with protein digestion for intact TVPs and patties. We conclude that pore-related rather than wall-related TVP properties dominated protein digestion of TVPs and patties. Larger macroscopic surface area and larger mean pore size contributed more to accelerating protein hydrolysis during digestion of TVPs and TVP-based patties than smaller wall density. These results suggest that altering TVP microstructure could potentially be a way to enhance protein digestibility of plant-based meat analogues.