Role of Starch Type in Gel-like Network Formation of Extruded Meat Analogs

Starches play a crucial role in determining the expansion, texture, and structural development of extruded meat analogs through their gelatinization behavior and interactions with proteins. In this study, corn, pea, tapioca, sweet potato, and potato starches were incorporated into soy protein-based formulations and processed under low-moisture and high-moisture extrusion conditions to investigate starch-dependent physicochemical properties. Amylose/amylopectin composition and starch pasting properties were evaluated, and the resulting extrudates were characterized in terms of expansion behavior, water-related properties, textural attributes, and internal structure. Distinct differences in pasting behavior were observed among starches, with potato starch exhibiting high peak viscosity and pea starch showing strong viscosity development during cooling. These differences were closely associated with extrusion outcomes, influencing expansion ratio and texture formation. In low-moisture extrusion, starches susceptible to thermal and shear degradation showed increased solubilization, whereas in high-moisture extrusion, enhanced starch gelatinization promoted starch-protein interactions and contributed to improved textural integrity and structural alignment. Overall, the results demonstrate that starch type is a key determinant of expansion behavior, texture, and structural organization in extruded meat analogs, highlighting the importance of starch selection and processing conditions for tailoring product quality.