Whey protein isolate-low acyl gellan gum Maillard-based conjugates with tailored technological functionality and antioxidant activity

Whey proteins are usually sensitive to ionic strength, pH change, and heat treatment, which may affect their functional properties. Maillard conjugation could be a facile approach to improve whey protein functionality. In this study, whey protein isolate (WPI; 0.6%, w/v) was conjugated to low acyl gellan gum (0.1, 0.2, and 0.3%, w/v) through the Maillard reaction at 90 °C for 90 min. The conjugate formation was confirmed by pH decrement, glycation degree (up to 9.44%), browning index, sodium dodecyl sulphate-polyacrylamide gel electrophoresis, and Fourier transform infrared spectroscopy. The surface hydrophobicity of WPI increased up to 2-fold upon conjugation, which led to a solubility decrease. However, the conjugated WPI had an improved interfacial activity, emulsifying activity (∼6%), foaming capacity (up to 63.64%), thickening ability (up to 24.67-fold), reducing power (up to 28.86-fold), and iron chelating activity (up to 3.31-fold). These findings may widen the industrial application of whey proteins.