The effect of meat processing methods on changes in disulfide bonding and alteration of protein structures: impact on protein digestion products

We investigated the effects of different pork preparation methods (cooked pork, emulsion-type sausage, dry cured pork, and stewed pork) on protein structures and in vitro digestion. Compared with raw meat, processed meats contained lower levels of free sulfhydryl groups (P < 0.05). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed different protein profiles for pork products treated without or with 5% beta ME, which indicated different extents of disulfide bond formation. Emulsion-type sausage showed significantly higher alpha-helix content and lower beta-sheet, beta-turn, and random coil contents than cooked pork (P < 0.05). Correspondingly, emulsion-type sausage and dry-cured pork had the highest values of surface hydrophobicity (P < 0.05). Proteome data showed that the long salting and drying times used for dry-cured pork as well as long-term high-temperature cooking of stewed pork might alter the accessibility of digestive proteolytic enzymes to the protein cleavage sites.