Tannin treatment was performed as described previously
(Sasaki et al., 2013). Briefly, 1% aqueous tannin (10 mL) was added
to fish sauce samples (100 mL), and supernatants were separated
from precipitates by centrifugation (8000g, 10 min).
Tannin-treated fish sauce (20 mL) samples were mixed with
CR11 or CR20 (700 mg) and were shaken for 1 h. Mixtures were
then filtered with coffee filter paper to separate supernatants from
chelate resins