Effect of selenium addition on phenylalanine ammonia lyase (PAL) activity and ethylene production in leafy vegetables

Minimally processed vegetables (MPV) are prepared and handled to maintain their fresh nature while providing convenience to the consumer, as ready-to-eat products. Cut operations during the MPV preparation induce activation of several biochemical processes leading, for example, to an increase of ethylene production and tissue browning. Enzymatic browning is the result of the oxidation of phenols that are produced starting by phenylalanine ammonia lyase (PAL). In plants, selenium (Se) is well known for its high potential of protecting biomembranes, eradicating free particles, and delaying senescence (Pezzarossa et al., 1999).