Effect of Low Temperature on the Exosmosises of Soluble Protein and Free Amino Acid from Spirulina (Arthrospira)

Folin procedure and ninhydrin method were adopted to determine the contents of soluble proteins and free amino acids in the cellular extravasations of Spirulina (Arthrospira) platensis (S_1) only found in the natron lakes of the Ordos Plateau,introduced S. (A.) platensis (S_2) and S. (A.) maxima (S_3) .The results showed that the lower the treating temperature was and the longer the treating time lasted,the higher the contents of soluble protein and free amino acids in the cellular extravasation of Spirulina (Arthrospira) would become.S_1 suffered the least membrane damage,which indicated that it had a stronger frost resistance than S_2 and S_3.The damage of low temperature to Spirulina (Arthrospira) membrane that was evaluated according to soluble proteins would be closer to its ;ractical damage than that according to free amino acids.