Scavenging effect for both DPPH and peroxide radicals was found to be dependent on the fraction concentration.
Viscozyme hydrolysates were superior to all other fractions in terms of their DPPH and peroxide scavenging activities as well as their phenolic content.
The superior performance of viscozyme hydrolysate could be
attributed to the fact that it is a multifunctional enzyme that
hydrolyzes the mannans and galactans that predominantly exist
in red algae. This is confirmed by the presence of high mannose
and galactose contents in the viscozyme hydrolysates as determined
by HPLC analysis.
It could be suggested from the above that the antioxidant activity
is related to the phenolic content, chain length and type of
sugars present in the algal extracts. Thus, enzymatic hydrolysis of
the sulfated polysaccharide algal extracts using viscozyme produced
fractions with high antioxidant activities (>90%) that are
comparable with those of the commercial ascorbic acid antioxidant.
They also showed high antibacterial activities that exceeded
those of the two commercial antibiotics tetracycline and
cefuroxime.