Physicochemical and Emulsifying Properties of Proteins From Caprine Whey Concentrates for Application in Fibril Formation

This study aimed to produce fibrils from goat whey protein concentrate (FWPCC), characterize their properties, and compare them with bovine whey protein fibrils (FWPCB). Goat whey protein concentrate (WPC) was obtained from sweet goat whey by ultrafiltration and diafiltration. Protein fibrils were subsequently formed at pH 2 by prolonged heat treatment. The physicochemical and emulsifying properties of both native WPC and its fibrils (FWPC) were systematically evaluated. Transmission electron microscopy (TEM) revealed distinct morphological differences: FWPCB formed long, linear fibrils without visible aggregates, whereas FWPCC fibrils were thinner and showed stronger inter‐fibrillar interactions, assembling into rope‐like or dense network structures. Zeta potential measurements indicated that fibrillation increased the positive charge of proteins, enhancing electrostatic repulsion and preventing visible aggregation. Fibril suspensions exhibited higher turbidity than native WPC, which decreased in the presence of SDS, highlighting the role of hydrophobic interactions in fibril stability. Electrophoretic analysis confirmed protein denaturation and fibril formation after heat treatment, while surface hydrophobicity remained unchanged. No significant differences were observed in the emulsifying activity index (EAI), although FWPCB showed a lower creaming index. These results indicate that variations in fibril morphology do not necessarily translate into improved emulsifying functionality. Overall, this study highlights that caprine whey proteins can form fibrillar structures with physicochemical and functional properties comparable to those of bovine whey proteins, contributing to their potential valorization as an alternative protein source.