Bangia fusco-purpurea Vegan Sausages: Orthogonal Experimental Optimization and Gel Formation Mechanism

To develop highly nutritious Bangia fusco-purpurea (BFP) vegan sausages, we investigated the effects of BFP, gluten, and xanthan gum–konjac gum–carrageenan complex gel (CG) on the gel strength and sensory quality of the sausages. The formulation process was optimized through single-factor and orthogonal tests, whereas the gel formation mechanism of the key factors was explored. The orthogonal test results showed that the optimal addition levels of BFP, gluten, and CG were 5%, 56%, and 37%, respectively. Variance analysis revealed that both gluten and CG significantly affected gel strength (p < 0.05), with gluten notably influencing the overall sensory quality (p < 0.05). Texture profile analysis (TPA) and rheological properties demonstrated that as gluten (33–37%) and CG (52–56%) concentrations increased, the gel strength and elastic modulus exhibited concentration-dependent enhancement. Further analysis of the sulfhydryl content, disulfide bonds, surface hydrophobicity, and microstructure revealed that higher gluten content promoted intermolecular disulfide crosslinking and hydrophobic group exposure, whereas CG contributed to physical filling via hydrogen and ionic bonds, resulting in a uniform and dense gel network structure. The synergistic effects of gluten and CG enhanced the gel properties of BFP vegan sausages, providing a theoretical foundation for the development of high-quality plant protein-based meat alternatives.