Improving Hydrophilicity of Wheat Starch via Sodium Dodecyl Sulfate Treatment

Abstract Starch is an important multifunctional ingredient for food, cosmetics, fuels, and pharmaceuticals. Naturally, starch is hydrophilicity, while its’ absorbability varies among botanical sources and physical or chemical modifications. In this study, fractioned A‐ and B‐type wheat starch granules show different physiochemical properties, B‐type granules have greater water and oil absorption capacity. After removing surface proteins with sodium dodecyl sulfate (SDS), starch granule morphology and crystalline structure are not apparently altered, except some shallow indentations are observed on the exterior of the starch granules. However, treatment with SDS affects the starch gelatinization, increases the swelling power, and solubility of starch significantly. Meanwhile, starch after removal of surface protein exhibits higher hydrophilicity and lower lipophilicity, especially for A‐type granules with larger size, the increases in water absorbability are more pronounced. This study gives us new insights in improving starch hydrophilicity through removing starch granule‐associated proteins, which may promote the application of starch in absorbent materials and desiccant.