Pea starch-fatty acid complexes: Chain length-concentration interplay governs multiscale structure, texture, and digestibility in gluten-free noodles

Gluten-free noodle formulations typically contain approximately 90% starch, which may contribute to limitations such as rapid digestibility. This study investigated the structural transitions and techno-functional responses of smooth pea starch noodles prepared using autoclave-treated starch-fatty acid complexes incorporating lauric, palmitic, or stearic acids (C12:0-C18:0) at concentrations of 5-15%. Fatty acid chain length and concentration jointly dictated complexation behavior: lauric acid showed a linear increase in complexation with concentration, whereas palmitic and stearic acids exhibited non-linear concentration responses. Lauric acid at 5% produced B+V-type polymorphs comparable to palmitic or stearic acids at 15%, indicating high complexation efficiency at lower concentrations. At the molecular level, palmitic acid at 15% promoted maximum structural ordering, yielding a single-helix content of 9.17% and V-type crystallinity. The identical mass fractal dimensions (α = -2.10) observed for the control and 15% stearic acid samples suggest that crystalline reinforcement occurred without disrupting lamellar packing. Notably, 15% palmitic acid induced the greatest structural ordering and the strongest textural reinforcement, while resistant starch increased to 28.53%. These findings demonstrate that fatty acid chain length and concentration act interdependently, together providing a strategy to modulate texture and glycemic functionality in gluten-free noodles.