Abstract:This study investigated the changes of nutrients and functional activities of Spirulina platensis in two dosage forms during digestion.Specifically，the powder and tablets were tested.They were treated by hydrolysis，acidolysis，high temperature，and high pressure steam，respectively，before the in vitro simulated digestion.The results were as follows：after continuous oral and gastrointestinal digestion，the free amino acid release of the powder in the treatment with high pressure steam was the most，2.25 folds that of acidolysis treatment（least）.The release of soluble protein in the powder in high temperature treatment was the most，1.75 times that of the control（least）.The content of soluble sugar and reducing sugar of the powder was high after acid hydrolysis and high temperature treatment，and the release of amino acid，soluble protein，soluble polysaccharide，and reducing sugar of the tablet was high after hydrolysis treatment.Free amino acids of S.platensis were mainly released after gastrointestinal digestion，and the soluble polysaccharides were mainly released after intestinal digestion.The acid-hydrolyzed powder and tablets after hydrolysis showed remarkable antioxidant effect，and the antioxidant effect was the best after oral and gastrointestinal digestion.