Changes of microstructure characteristics and intermolecular interactions of preserved egg white gel during pickling

Abstract

Changes in gel microstructure characteristics and in intermolecular interactions of preserved egg whites during pickling were investigated. Spin-spin relaxation times of preserved egg whites significantly decreased in the first 8 days and remained unchanged after the 16th day. SEM images revealed a three-dimensional gel network, interwoven with a loose linear fibrous mesh structure. The protein gel mesh structure became more regular, smaller, and compacted with pickling time. Free sulfhydryl contents in the egg whites increased significantly, while total sulfhydryl contents dramatically decreased during pickling. The primary intermolecular forces in the preserved egg white gels were ionic and disulfide bonds. Secondary forces included hydrophobic interaction and relatively few hydrogen bonds. During the first 8 days, the proportion of ionic bonds sharply decreased, and that of disulfide bonds increased over the first 24 days.

Keywords: 5,5′-Dithiobis(2-nitrobenzoic acid) (PubChem CID: 6254); Acetic acid (PubChem CID: 176); Copper sulfate (PubChem CID: 24462); Disulfide bond; Glutaraldehyde (PubChem CID: 3485); Glycine (PubChem CID: 750); Intermolecular force; Microstructure; Preserved egg white gel; Sodium chloride (PubChem CID: 5234); Sodium dodecyl sulfate (PubChem CID: 3423265); Sodium hydroxide (PubChem CID: 14798); Urea (PubChem CID: 1176); β-Mercaptoethanol (PubChem CID: 1567).