Studies on the functional properties of water extracts of the brown seaweeds Sirophysalis trinodis and Polycladia myrica

The functional properties of water extracts of Sirophysalis trinodis and Polycladia myrica were evaluated. Extracts contain 2.54 ± 0.21 and 2.40 ± 0.14% proteins, respectively. The maximum nitrogen solubility was observed at pH 2 in the presence of water. The fat absorption capacity of S. trinodis (2.26 ± 0.22 g oil g−1 sample) and P. myrica (2.65 ± 0.11 g oil g−1 sample) extracts was high, but the water holding capacity was low. The emulsifying capacity of extracts was not good because of the low amount of protein. The addition of 0.5 M NaCl to the extract showed the maximum emulsion stability at pH 2. Measurement of foam stability also showed that water extracts were affected by the time and pH. Differential scanning calorimetric (DSC) analysis revealed thermal transitions at about 183.45 and 180.76 °C, respectively, for S. trinodis and P. myrica. Unlike brown seaweed medicinal effects, the results showed that their water extract could not be a replacement for other vegetable extracts.