Unlocking the potential of insoluble date fruit (Phoenix dactylifera L.) fibres in extruded soy protein-based meat analogues

This study explored the potential of date fruit fibre (DF) in high-moisture extrusion of soy protein isolate (SPI)-based meat analogues (HMMAs). Five different DF concentrations were used: 0, 5, 10, 20, and 30 % w/w. While the degree of texturisation was not affected, DF markedly influenced the extrudates' textural properties. At <10 % DF, the extrudates were softened, whereas at >10 % DF, the hardness increased, resulting from a more compact protein arrangement during gel formation. Results showed that DF promoted a more organised and tightly bound protein gel network, imparting strain-hardening behaviour. Microstructural analysis revealed that DF acted as a filler by occupying voids and bridging the SPI gel network, thereby enhancing elasticity. Thermal stability decreased at moderate levels (10–20 % DF) and remained similar to that of the control (0 %), at higher inclusion (30 %), consistent with textural and rheological outcomes. DF addition also reduced the extrudate brittleness and contributed to a desirable brown and reddish, meat-like appearance. These findings offer valuable insights into texture modulation and product development for plant-based meat substitutes.