3.4. Protein cross-linking
The meat proteins were separated by gel electrophoresis for the
evaluation of reducible myosin cross-linking as determined by the
gain of myosin heavy chain (MHC) after treatmentwith DTT in comparison
to without DTT. Hence, the meat proteins were separated in both
their reduced and non-reduced state (Fig. 3, left panel). Staining by
Sypro Ruby gel stain showed that the intensity of the protein bands of
both MHC and actin were more intense in samples after treatment
with DTT as compared to the non-reduced samples without DTT. This
indicates that protein polymers were reduced to yield a higher concentration
of monomer MHC and actin, and indirectly that reducible
protein cross-links are generated during the production of the meat
emulsions. Recent work in our laboratory have shown that DTT,
commonly used as reducing agent in gel electrophoresis, is able to partly
break thiol–quinone adducts formed between 4-methylbenzoquinone
and β-lactoglobulin (unpublished data). Hence, from the SDS-PAGE
analysis in the present study, it is not possible to differentiate between
disulfide protein–protein cross-links and phenol-mediated protein–
phenol–protein cross-links in the meat emulsions.