Valorization of corn silk protein: pH-driven structural modulation for emulsion-templated oleogel fabrication

Corn silk, an underutilized agricultural by-product, represents a promising yet largely unexplored source of plant proteins. In this study, corn silk protein was extracted via alkaline solubilization-acid precipitation, and its structural and functional properties were systematically investigated through pH modification (pH 3-11). Scanning electron microscopy revealed that control corn silk protein consisted of relatively uniform sub-spherical particles with diameters of 1.5 to 1.6 μm, while secondary structure analysis indicated that β-sheet and β-turn were the dominant conformations. Furthermore, pH 11 treatment was associated with improved solubility and emulsifying performance, which may contribute to enhanced interfacial stabilization. Specifically, C11 showed higher solubility (75.8%), emulsifying activity index (15.11 m²/g), and emulsifying stability index (214.11 min) than the control corn silk protein and other groups, resulting in improved emulsion stability. Corn silk protein-based oleogels with various water-to-oil volume ratios (5/5, 4/6, 3/7, 2/8, 1/9) were prepared using an emulsion-templated method (oven-drying at 40 °C for 24 h). At a water-to-oil volume ratio of 3/7, corn silk protein formed a relatively uniform protein network that effectively entrapped and stabilized the oil phase, resulting in an oleogel with a soft-solid structure, enhanced hardness, and superior oil-holding capacity (98%). This study suggests the feasibility of extracting proteins from corn silk and subsequently using them to prepare corn silk protein-based oleogels.