Generally enzymatic browning in fruit and vegetable is assumed
to be a total consequence of reaction between polyphenol substrates and oxygen with PPO and POD. The primary enzymes
responsible for browning reaction is PPO, which is able to catalyze
the hydroxylation of monophenols to o-diphenols and the oxidation of o-diphenols to their corresponding o-quinones (Richard&
Gauillard, 1997). POD is another oxidoreductas enzyme involved
in enzymatic browning since diphenols may function as reducing
substrates in its reaction (Chisari, Barbagallo,&Spagna, 2007).