Physicochemical and functional properties of whey protein-Yeast beta-glucan conjugates formed by glycosylation

There is a growing interest in the development of digestive protein-stabilized emulsions due to their potential applications in the field of functional foods. Glycosylation is a biochemical process that enhances protein functionality through the covalent attachment of sugar moieties. This study aims to synthesize whey protein-Yeast beta-glucan (YG) conjugates via the dry heat method, examine the effects of various glycosylation reaction conditions on the functional properties of whey protein isolate (WPI), and characterize the properties and structures of the resulting conjugates. The results demonstrated that under different water activity conditions (0.49, 0.63, 0.74), the degree of glycosylation for WPI-YG conjugates with ratios of 1:1, 2.5:1, and 1:1, and reaction times of 24 hours, 72 hours, and 96 hours were 7.78% ± 0.19%, 9.6% ± 0.1%, and 7.63% ± 0.38%, respectively. Fourier-transform infrared (FT-IR) and SDS-PAGE spectroscopy confirmed the formation of conjugates. Scanning electron microscopy (SEM) revealed that WPI can covalently bind with glucan, resulting in smoother and denser surfaces of the conjugates. Circular dichroism and X-ray analysis indicated that glycosylation altered the secondary structure of WPI. In conclusion, this study provides valuable insights into developing functional properties of glycosylated products for food ingredients. • The complex (WPI-YG) was fabricated using whey protein (WPI) and yeast beta-glucan (YG) as raw materials by the dry heat method. • Glycosylation improves the functional properties of conjugates and enhances the antioxidant properties of the WPI. • The Maillard reaction (MR) enhances the solubility of WPI, thereby expanding its application within the food industry.