Tuning Whey Protein Properties: Ohmic Heating Effects on Interfacial Properties and Hydrophobic and Hydrophilic Interactions

Ohmic heating (OH) emerged as an alternative processing method for food preservation and has more recently been used to modify the functional properties of proteins. This study aimed to evaluate the effects of OH on the interfacial properties of whey proteins (WPC) and its interactions with hydrophobic and hydrophilic compounds. WPC solutions (8% w/w) were subjected to electric field intensities ranging from 0 to 50 V·cm−1 until reaching 80 °C. Structural and physicochemical parameters, including free sulfhydryl content, zeta potential, surface hydrophobicity, intrinsic fluorescence, and solubility, were analyzed. Protein–ligand interactions were also evaluated using β-carotene and caffeic acid as model compounds. The results indicated that moderate electric field intensities (30 V·cm−1) promoted increased surface hydrophobicity and intrinsic fluorescence, suggesting protein unfolding and exposure of hydrophobic regions. Higher electric field intensities (40–50 V·cm−1) led to aggregation, reducing solubility and binding affinity to β-carotene. Conversely, OH processing increased the interaction of WPC with caffeic acid due to enhanced exposure of hydrophilic binding sites. These findings provide insights into the modulation of whey protein interfacial properties through OH and highlight its potential for tailoring protein functionality in food formulations.