Other methods involve fractionation of a green tea extract by
selective precipitation of catechins with a precipitation agent
[21] and different adsorption separation processes. Several adsorbents
have been tested, such as lignocellulose [22,23] and lignocellulose
copolymerized with N-vinylpyrrolidone [24], activated
carbon [25], polyvinylpolypyrrolidone [26,27], polyamide [28],
poly(acrylamide-co-ethylene glycol dimethacrylate) [29] and different
macroporous polymeric resins.