Can item despawn rate be changed in minecraft?

Solution 1:

I don't know if you can do it with a plugin but it is possible with command blocks.

Basic concept: Set the age to the desired amount for newly dropped items

Setup:

/scoreboard objectives add newItem dummy

Loop:

/entitydata @e[type=Item,score_newItem_min=!1] {Age:<Despawn Rate>}
/scoreboard players set @e[type=Item] dummy 1

Replace <Despawn Rate> with 6000 - Life length of item in terms of ticks.