Sulfhydryls in antioxidant-washed beef heart surimi

The role of water- and lipid-soluble antioxidants (propyl gallate, PG; α-tocopherol, α-Toc; ascorbate, Asc; tripolyphosphate, TPP) in protecting sulfhydryls in beef heart surimi was assessed. Sulfhydryl content was measured by reacting surimi samples with 5-5′-dithio-bis(2-nitrobenzoic acid) (DTNB). Formation of disulfide linkages in fresh and stored (7 days on ice) surimi and its salted paste (sol) was examined by electrophoretic analysis in the presence and absence of dithiothreitol. Loss of sulfhydryls occurred during storage in control (water-washed) and Asc-washed surimi, but the loss was prevented by PG, α-Toc, and TPP. Sulfhydryls were decreased in all samples except PG-washed surimi by the addition of 0.6 M NaCl. Formation of disulfide as well as nondisulfide covalent linkages was evident in control and Asc-washed surimi samples. The nondisulfide linkages were almost completely absent in the presence of PG, α-Toc, and TPP.