The fatty acid content of the extracted oils was measured on the
GC–FID by response factor for each fatty acid, using external
curves, and their amounts were then calculated as mg of fatty acid
per g of oil (mg/g). The results summarised in Table 2 revealed that
the total fatty acid (TFA), DHA and EPA contents of SH and SB oils
were not significantly different (TFA: 795.0 and 794.8 mg/g; DHA:
78.8 and 79.7 mg/g; EPA: 77.6 and 78.0 mg/g, respectively). This
result was expected as the oils extracted from the two samples
(SH and SB) came from the same source (head section) while the
shells contained in the SB sample reduced yield by 20%. The SM
sample was not only a poor source of oil, but the extracted oil contained
significantly less fatty acids than SH and SB (p < 0.01) (TFA:
574.3 mg/g; DHA: 54.2 mg/g; EPA: 56.0 mg/g). Overall, the levels of
PUFAs contained in the SFE extracts of P. borealis by-products were
comparable to the levels found in traditional food sources of x-3
PUFAs (i.e. salmon) and fish oils available on the market which
were extracted using conventional methods (Table 3). The marine
crustacean krill, extracted by SFE has higher levels of both EPA and
DHA and krill meal represents an exceptional source of EPA. Previous
studies of hake and sardine by-products have demonstrated
the potential of this method for generation of a value added product
from a previously discarded waste stream. The yield and PUFA
profiles generated by SFE for P. borealis by-products provide rationale
that this source and method warrant further investigation as a
x-3 fatty acids natural health product with potential for commercialisation.
While the fatty acid composition of EPA and DHA in
krill is superior; 17.4% and 12.4%, respectively (Tou, Jaczynski, &
Chen, 2007), SFE of Northern shrimp by-products is an attractive
strategy as it does not compromise their primary use as food. Furthermore,
by using this technology, the residual biomass is available
for further extraction of additional bioactive materials (i.e.
chitin, polysaccharides).