Effect of ethanol concentration on conjugates of gallic acid and whey protein isolate: structural and functional properties

Abstract This study investigated the impact of varying ethanol concentrations on the functionality and structure of conjugates of gallic acid (GA) and whey protein isolate (WPI). The solubility, total phenolic content, and sulfhydryl group content of the conjugates significantly decreased with increasing ethanol concentration. The structure of the conjugates was altered as indicated by changes in their infrared and fluorescence spectra. By measuring the emulsification and foaming properties, we found that ethanol improved the functional properties of the conjugates. The study examined the influence of ethanol on the conjugates of polyphenolic compounds with whey protein, broadening the scope of research on protein modification. Furthermore, it provided a scientific basis for the future development of novel functional foods.