Shrimp (Solenocera prominentis) shells were collected
from a local fish market (Keelung, Taiwan) and stored
under frozen temperature ()20 C) until further pro-
cessing. Soybean was purchased from a local super-
market and stored at ambient temperature (25 C).
Chemicals (sodium chloride, oxalic acid, potassium per-
manganate, hydrochloric acid, sodium acetate, potassium