Effect of Hydrothermal Processing on Physico-chemical Properties and Antioxidant Activity of Edible Brown Seaweed Sargassum wightii

Indian edible brown seaweed, Sargassum wightii, hydrothermally processed (by boiling and microwave treatment) until an edible texture was attained and then extracted in different solvents, including acetone, chloroform, ethyl acetate, and methanol to obtain dry extracts. Swelling capacity and oil holding capacity of the processed seaweed was found to be significantly higher (p < 0.05); while water holding capacity was significantly lower (p < 0.05) after thermal processing as compared to the control. There was significant (p < 0.05) increase in the phytochemical content and antioxidant activity after thermal processing compared to the control. Phenolic and flavonoid compounds were found to be well extracted in the less polar solvents, i.e., chloroform and ethyl acetate and these results correlated well with the DPPH free radical scavenging activity. Results suggested that bioactive compounds in S. wightii are stable towards thermal treatment making this seaweed a potent candidate to formulate processed functional food products.