Valorizing okara in plant-based ice cream: A dual-mechanism hydrocolloid strategy for texture and stability

The valorization of agricultural by-products is essential for developing circular food systems. Okara (soybean pulp), a nutrient-dense but underutilized residue, presents textural challenges—grittiness and matrix instability—that limit its use in refined products like frozen desserts. To enable its upcycling, this study engineered an okara-fortified soy ice cream (OFSI) stabilized by a ternary hydrocolloid system of sodium alginate, agar, and κ-carrageenan. A simplex-centroid mixture design (0.50% total hydrocolloids) revealed a fundamental dichotomy: sensory creaminess and acceptability followed linear models dominated by κ-carrageenan, whereas physical stability (melting resistance, overrun) was governed by synergistic interactions among all three components. The optimized ternary blend H6 (0.083% sodium alginate, 0.083% agar, 0.334% κ-carrageenan) delivered superior functionality. It achieved the highest overall sensory scores 7.96 ± 0.38, alongside excellent melt resistance (0.47 ± 0.02 g/min) and overrun (31.0 ± 1.2%), effectively masking fiber grittiness. This work provides a dual-mechanism stabilization framework and a validated formulation template for transforming fibrous by-products into high-quality, sustainable plant-based desserts. Future applications of this framework can be directly utilized to guide the structural engineering of other fiber-rich upcycled ingredients across various semi-solid and frozen vegan food matrices.