Effects of deodorisation methods on volatile compounds, chemical properties and antioxidant activities of fucoidan isolated from brown seaweed (Sargassum sp.)
2017
Fucoidan is a unique marine algae derivative that exhibit many bioactivities. However, the distinct unpleasant odour limits its application in food products. In the present study, fucoidans were deodorised using three different methods; activated carbon, (Fac), ion exchange resin (Fresin) and calcium carbonate (FCaCO3). Subsequently, the effects of deodorisation on the chemical properties (FTIR, fucose and sulphate content), volatile compound compositions (GC-MS) and antioxidant activity (total phenolic content, DPPH, superoxide and hydroxyl radical scavenging) of fucoidan were evaluated. A total of 46 volatile compounds were successfully identified in all samples using headspace-solid phase microextraction (HS-SPME) and analysed using gas chromatography mass spectrometry (GC-MS). It was found that 2,4-bis(1,1-dimethylethyl)phenol was one of the odour active compounds in Fsar, which reduced significantly after deodorisation. All deodorised samples showed no significant (p>0.05) differences in fucose, sulphate content and total phenolic content from that of Fsar except for Fresin. In terms of antioxidant activity, the DPPH scavenging activity in FCaCO3 (3%) was significantly higher, (p<0.05) compared to that of Fsar. All deodorised fucoidans were observed to show significantly higher (p<0.05) superoxide anion scavenging activity compared to that of Fsar. Hydroxyl radical scavenging activity of Fresin (1:100), Fresin (3:100), and FCaCO3 (5%) showed a significant increase (p<0.05) compared to Fsar. Overall results confirm that the deodorisation methods were successful in reducing the odour and did not alter its chemical compositions, while in some cases, enhance the antioxidant activities.
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