Effect of structural characteristics on functional properties of textured vegetable proteins

Meat analogues are predominantly composed of a pre-structured form of protein called textured vegetable protein (TVP) that is designed to mimic the fibrous structure of animal muscle meat. Limited information is available regarding the link between structural characteristics of TVPs and their functional properties. This study investigated the relationships between the structural characteristics of commercial TVPs and (a) their rehydration behaviour, as well as (b) the mechanical properties and serum release (cooking loss and expressible liquid) of patties prepared from these TVPs. The micro-and macrostructural features of thirteen commercial TVPs were quantified using X-ray microtomography. Apparent density (205-1042 kg m-3), porosity (27.1-80.9%), pore size (251-4790 mu m), wall thickness (108-657 mu m), and wall density (597-1515 kg m-3) varied largely across sam-ples. In the early stages of water absorption, thicker walls promoted the absorption of larger volumes of water. In contrast, the maximum water absorption capacity as well as water holding capacity were higher for TVPs with thinner walls and higher porosity, highlighting the impact of structural features of TVPs on water absorption during rehydration. Significant positive correlations between cooking loss and expressible liquid indicated that patties with higher serum release during cooking also tended to release more during compression. TVPs with thicker walls resulted in stiffer patty batters, and TVPs with smaller pores resulted in stiffer grilled patties. We conclude that the structural characteristics of TVPs influence their rehydration behaviour and various functional properties of patties made with them.