Structural, functional, and physicochemical characterization of fermented whey protein concentrates recovered from various fermented-distilled whey

Abstract

The utilization of whey has become a challenge with the significant growth in the production of cheese and coagulated milk products. Consequently, we have developed cost-effective and waste-free production technologies for processing whey disposal into a variety of high-quality, value-added food products at the industrial level. This work constitutes a research on the impact of various alcoholic fermentations on functional, structural, and physicochemical properties of fermented whey proteins recovered from whey-based spirit production effluent. The results showed that surface hydrophobicity and sulfhydryl groups of fermented whey protein concentrates (FWPC) increased significantly in comparison with native whey protein concentrate, while the zeta-potential and particle size of non-supplemented FWPC and low-supplemented FWPC were not substantially affected by fermentation. Furthermore, the outcomes indicated that the non-and low-supplemented whey fermentation led to the improvement in the solubility of FWPCs dispersions, and enhancement in the emulsifying activity and stability of FWPCs. Size exclusion chromatography and SDS-Page results also demonstrated significantly increased β-Lg content in FWPCs, which might be attributed to the reinforcement of the β-Lg intramolecular and noncovalent bonds. The enhancement in functionality was probably due to the partially unfolded whey protein molecules, exposing more hydrophobic amino acid residues, thus making the protein more amphiphilic and capable. Nevertheless, high-yield alcoholic fermentation led to critical changes in the structural properties of whey proteins as evidenced by SEM results. Therefore, our findings suggested that the application of recovering FWPCs after producing premium quality potable whey-based spirit from the presence of non-and low-lactose supplemented whey is fully proposed as an industrially recommended alternative for food-grade protein production. • Fermentation process significantly increased general properties of FWPC. • More amphiphilic and capable proteins recovered due to exposed hydrophobic amino acids. • Increased β-Lg content in fermented whey protein leads to better functionality. • FWPC is proposed for manufacturing food-grade protein at the industrial level.