Improving Freeze–Thaw Stability of High-Moisture Extruded Plant-Based Meat: A Synergistic Strategy Combining Glucose Oxidase, Phytase and Tamarind Gum

Plant-based meat analogs, particularly those produced by high-moisture extrusion, are prone to quality deterioration during frozen storage due to poor freeze-thaw stability. This study aimed to develop a synergistic stabilization strategy for soy protein isolate (SPI)-based extrudates using glucose oxidase (GO), phytase (PA), and tamarind gum (TG). The effects of individual additives (GO, PA, TG) and their combination (GO + TG) were systematically evaluated over seven freeze-thaw cycles, with a pure soybean-protein meat analog (PSM) as a control. The results showed that repeated freeze-thaw cycles severely degraded the control groups, leading to reduced water-holding capacity (WHC), increased hardness, and color darkening. While all additives mitigated these changes, the GO + TG combination exhibited the most pronounced protective effect, maintaining the highest WHC (0.993 ± 0.000), optimal texture (hardness 66.0 ± 0.0 N, elasticity 3.7 ± 0.0 mm), and minimal color variation. Structural analyses revealed that GO + TG effectively suppressed protein oxidation, minimized sulfhydryl loss, preserved protein secondary and tertiary structures, and inhibited the conversion of immobilized water to free water. The synergistic mechanism is attributed to the formation of a dual-network structure, wherein GO enhances covalent cross-linking and TG provides steric stabilization. This study offers a practical and effective approach for enhancing the freeze-thaw stability of extruded plant-based meat products, with potential industrial applications.