Enhanced functionality of fermented whey protein using water kefir

Abstract

ABSTRACT This research is part of an effort to enhance fermented whey proteins’ quality and nutritional value. In this research, we investigated the feasibility of using a natural fermentation approach on whey proteins. We determined the protein digestibility, non-nutritive compounds (including phenolic compounds and saponins), and microbiological quality of water kefir-fermented whey proteins. Due to the water kefir-induced fermentation of whey proteins, the protein digestibility improved from 88.48 to 94.33%. The protein quality of fermented whey proteins has been modified after the water kefir fermentation, as observed with the changes in the secondary protein structure components, especially α-helices (decreased from 10.58 to 8.52%) and random coil (increased from 12.25 to 17.33%). In addition, their water solubility, surface hydrophobicity, and surface charge changed significantly (P < .05) during the fermentation time; 88.44 to 94.11%, 387.23 to 272.7 a.u. and −30.06 to −34.93 mV, respectively. Furthermore, water kefir is an excellent source of fermenting microorganisms, including lactic and acetic acid bacteria and yeast. Thus, the water kefir fermentation approach could be an effective, practical, non-thermal approach for altering whey proteins.