Impact of conjugation of whey protein concentrate with different carbohydrates: Monitoring structural and technofunctional variations

Abstract

This study utilized whey protein concentrate (WPC) as the primary protein source, employing the Maillard reaction to link it with three distinct carbohydrates: lactose, maltodextrin, and gum Arabic. Mixtures were prepared with a 1:4 protein-to-carbohydrate ratio, and conjugation was performed using dry heating at a temperature of 60 °C, 50% relative humidity for 8 h processing time. Under the same conditions, native WPC was heated as a control group. The formation of conjugates was tracked by monitoring absorbance changes, browning index (BI), and reduction in free amino groups (FAG). All conjugates exhibited significant loss of FAG, correlating with an increase in BI. Shifts in protein fingerprint bands observed via Fourier Transform Infrared Spectroscopy suggested potential protein-carbohydrate interactions, while X-ray diffraction showed increased sample crystallinity post-conjugation. Solubility assessments across pH levels (3.0–8.0) indicated a 10–13% rise in solubility for conjugated samples compared to mixtures, broadening their potential applications. Moreover, the emulsion stability index demonstrated improved stability after conjugation. Overall, the Maillard reaction-mediated conjugation enhanced the solubility and stability of emulsions.