The synergistic effects of NaOH and NaCl on the gel properties, digestive characteristics, and product quality of salted preserved egg white

Salted preserved egg is a traditional Chinese egg product, yet research on it remains scarce. In this study, salted preserved egg was pickled using a curing solution without the addition of heavy metal compounds. The gel properties, digestive characteristics, and product quality of the salted preserved eggs were systematically examined. Specifically, the results indicated that during the curing process, the opacity and Hunter whiteness of salted preserved egg whites (SPEW) decreased, while the pH value, NaCl content, and protein digestibility increased significantly. SDS-PAGE and free sulfhydryl group analyses revealed that the proteins in SPEW underwent gradual decomposition during the pickling process, enhancing their digestibility. Overall, salted preserved eggs marinated for 12-day or 15-day marination represent more suitable choices. This study offers direct insight into the processing of heavy metal-free salted preserved eggs and establishes a foundation for investigating the gelation of proteins induced by alkali, salt, and heat synergies.