(enzyme:substrate ratio of
1:50, w/w) at pH 8 at 37 ◦C for 240 min, respectively. Hydrolysis
was carried out in a thermally controlled incubator under constant
stirring. Both reactions were terminated by heating at 95 ◦C for
10 min in a water bath, followed by the lyophillization. Finally,
the digested samples were stored at −20 ◦C until the assay of ACE
inhibition.