*3.5. Amino Acid Composition of PSC*

The lyophilized PSC samples were hydrolyzed with 6 M HCl at 110 ◦C for 24 h without oxygen and then vaporized. The hydrolysates were then analyzed by using a Hitachi amino acid analyser L-8800 (Hitachi, Tokyo, Japan). The content of Hyp was accurately measured according to the protocol described by Tang et al. [1].
