Construction and Textural Properties of Plant-Based Fat Analogues Based on a Soy Protein Isolate/Sodium Alginate Complex Coacervation System

This study focused on the preparation of microcapsules that simulate adipose tissue cells via complex coacervation, followed by the formation of block-like fat analogue products through gelation. The results indicated that microcapsules obtained by encapsulating coconut oil with soy protein isolate (SPI) and sodium alginate (SA) through a complex coacervation process could serve as effective fat substitutes in meat products. When the mass ratio of SPI to SA was 3:1, the core-to-wall mass ratio was 1:1, and the total wall material concentration was 3% (<i>w</i>/<i>v</i>), the oil loading rate of the microcapsules reached 39.17%. The particle size of the oil-loaded microcapsules was mainly distributed between 40-180 μm, which was comparable to the size of fat cells in animal adipose tissue. Microcapsules (50%, <i>w</i>/<i>w</i>) were mixed with a 5% (<i>w</i>/<i>v</i>) curdlan dispersion and heated at 95 °C for 60 min to form fat analogues. The fat analogues demonstrated significantly reduced cooking loss, enhanced textural rigidity, and superior chew resistance, achieving performance metrics comparable to those of natural adipose tissue. This dual-phase strategy-combining interfacial engineering of lipid microcapsules with polysaccharide-mediated gelation-provides a promising approach for developing sustainable, plant-based fat alternatives in meat product reformulation. The methodology not only addresses texture and flavour challenges in fat replacement but also enables precise control over lipid content, supporting applications in healthier food systems.