Fucoxanthin content in New Zealand Undaria exhibited location
variation and also varied depending on the life cycle of the seaweeds
indicating the possible biological significance of this pigment
in seaweeds. U. pinnatifida harvested from Port Underwood
had higher fucoxanthin content in the blade than Pelorus Sound.
U. pinnatifida harvested in Port Underwood during winter contained
a significant amount of fucoxanthin. Fucoxanthin was also
found in the sporophyll of U. pinnatifida throughout the growing
season, even though its level was significantly lower than that in
the blade. However as sporophyll is often discarded as it is not consumed
as food, it can instead be a useful bioresource for fucoxanthin.
Processed New Zealand U. pinnatifida had comparable amount
of fucoxanthin, as well as antioxidant activity, compared to commercial
wakame products analysed. However as processing reduced
the amount of fucoxanthin, an effective stabilisation
method will be necessary to apply fucoxanthin in nutraceuticals
and formulation of functional foods. The pathogen free aquatic environment and relative absence of inorganic toxins of New Zealand
waters may further give New Zealand U. pinnatifida a competitive
edge in the production of high quality fucoxanthin. In this
study, the uniqueness of the antioxidant activities of New Zealand
U. pinnatifida was their significant radical scavenging activities and
reducing capacities compared to commercial fucoxanthin that
exhibited either a stronger scavenging activity or reducing capacity
but not both. This could be due to the different growing environment
of New Zealand U. pinnatifida that may produce unique
chemical compounds possessing antioxidant activities that reacted
in both antioxidant assays.