The flight data recorders have been sent to a laboratory in Farnborough in southern England under the supervision of experts from the International Civil Aviation Organisation (ICAO), the commission said in a statement.
According to the statement, Ukraine did not extract the information from the black boxes before handing these over to international experts, Xinhua reported.
Earlier Monday, the rebels, including self-proclaimed prime minister of the Donetsk People's Republic, Alexander Borodai, handed over the flight recorders of the ill-fated jetliner to Malaysian officials at a ceremony in the eastern Ukrainian city of Donetsk.
A refrigerated train with the remains of the victims arrived in the Ukrainian city of Kharkiv, outside rebel territory, Tuesday.
The officials said that 282 bodies as well as recovered parts of 16 other bodies were loaded on to the refrigerated train.
Flight MH17, a Boeing 777, was flying from Amsterdam to Kuala Lumpur when it crashed after being hit by a missile in Ukraine near the Russian border last Thursday, killing all 298 passengers and crew on board.
This is the second major tragedy for Malaysia Airlines this year after flight MH370 with 239 passengers and crew on board went missing while going from Kuala Lumpur to Beijing March 8. The flight remains untraced till date despite intense international search efforts.