Plasma‐ and Gamma‐Irradiation‐Modified Potato Starch Powders With Enhanced Water Absorption for Potential Biomedical Applications

ABSTRACT

Water absorption ability is a critical property for starch‐based materials used in absorbent and hemostatic applications. This study investigated the effects of plasma treatment and gamma irradiation on the water absorption behavior and physicochemical properties of modified potato starch powders. Three modified potato starch powders were examined: acetylated distarch phosphate (ADP), sodium chloride‐modified ADP (MADP), and sodium carboxymethyl starch (SCS). Plasma treatment significantly increased the water absorption capacities of ADP, MADP, and SCS powders from 1021.9 ± 55.1% to 1485.0 ± 93.2%, from 1328.4 ± 55.8% to 1489.8 ± 68.5%, and from 1139.5 ± 52.6% to 2000.1 ± 73.7%, respectively. Fourier‐transform infrared spectroscopy revealed increased carbonyl‐related absorbance after plasma treatment, suggesting that plasma‐induced surface oxidation enhanced hydrophilicity and promoted hydrogen bonding interactions with water molecules. In contrast, gamma irradiation produced starch‐dependent effects. Water absorption in MADP decreased from 1328.4 ± 55.8% to 1154.3 ± 29.4%, whereas irradiated SCS powders exhibited increased water absorption from 1139.5 ± 52.6% to 1663.0 ± 10.8%. In contrast, water absorption of ADP powders was completely lost after gamma irradiation. The enhanced water absorption behavior of irradiated SCS powders may be associated with radiation‐induced chain scission, increased exposure of hydrophilic carboxymethyl groups, and reduced particle size. Scanning electron microscopy further revealed reduced particle size in treated SCS powders, which may contribute to increased surface area and enhanced water absorption. Thermogravimetric and differential scanning calorimetry analyses demonstrated that gamma irradiation altered the thermal stability of the starches without significantly changing their crystalline structures. In addition, the pH values of all treated starch powders remained within the range of 5–7, which is generally considered suitable for biomedical‐related material environments. These findings demonstrate that plasma treatment and gamma irradiation induce distinct physicochemical modifications in different starch structures and may provide useful strategies for developing starch‐based absorbent materials with potential hemostatic and biomedical applications.