Mechanism of the amelioration of the protein digestibility of whole marinated eggs by strong alkali pickling: Physicochemical properties, gel structure, and proteomics

Marinated egg is one of the traditional egg products in China; however, its low digestibility has limited its further industrial application. In this study, the mechanism involved in the amelioration of the protein digestibility of whole marinated eggs by strong alkali pickling was investigated. The results revealed that the water content of strong alkali-pickled whole marinated egg (SPME) exhibited an increasing trend during the alkali pickling process. Furthermore, as the pickling process progressed, the hardness, net charge, and β-sheets of the SPME first increased and then decreased, and the stability of the secondary structure of the SPME gradually decreased. In addition, long-term strong alkali pickling damaged the gel properties and protein structure of SPME, which resulted in the degradation of the protein. Thus, the alkali pickling significantly enhanced the digestibility of the SPME protein and the number of peptides present in the enzymolysis product of SPME. In summary, strong alkali pickling effectively improved the protein digestibility of marinated egg.