3.2. Lipid oxidation (TBARS)
Lipid oxidation of salmon was measured using thiobarbituric
acid reactive substance (TBARS) (Fig. 2). Increases in TBARS value
indicate more lipid oxidation occurred. Salmon packaged in the CPP
pouches had the highest TBARS values throughout the entire
storage time due to the high OP of CPP. Until week 5, TBARS values
of salmon packaged in ALOX, SIOX, and FOIL pouches were not
significantly different from each other. However, TBARS values of
salmon packaged in SIOX pouches were significantly higher than
that of salmon packaged in ALOX and FOIL pouches after week 8.
Therefore, there was more lipid oxidation had occurred in salmon
packaged in SIOX pouches. This may primarily attributed to the
higher OP of retorted SIOX. As the OP of the SIOX increased,
additional oxygen came into the package, increasing the lipid
oxidation of the salmon. However, substantial increases in lipid
oxidation of the salmon did not happen right after retorting when
OP of SIOX had increased considerably. Instead it increased steadily
until week 5 and then it sharply increased at storage times between
week 8 and 12. It took time for the salmon packaged in SIOX to
reach same deterioration level of the salmon packaged in CPP
because the OP of SIOX was still 100 times lower than that of CPP
after retorting.
TBARS values of salmon packaged in ALOX pouches were only
slightly higher than that of salmon packaged in FOIL pouches after
week 10.