Na-ALG solution (1% w/v, 200 mL of deionized water+50 mL of ethanol) was mixed after adding an amount of NaIO4 (100% oxidation degree of the uronic acid units) in the dark at room temperature to obtain ADA. The reaction was stopped after 24 h by the addition of ethylene glycol (20 mL) to reduce the excess periodate. The reaction mixture was stirred for 2 h at RT [20,22,23]. After reaction, the solution was dialyzed using dialysis tube (MWCO, 1000) against deionized water with several changes of water until the dialyzate was periodate free. The dialyzate was then lyophilized to obtain the product. ADA was assessed by FTIR and the degree of oxidation was determined by the hydroxylamine hydrochloride method [36]. The values were expressed as the mean±standard error (n=5).