I clearly saw smoke coming from the engine. The plane made some loops over the Adriatic Sea."
Guessing he means circled ... doubtless a translation matter. "Smoke coming from engines" is vague enough to mean ... anything.
(...) Lufthansa was according to Peeters very vague about the cause of the smoke.
Matches his testimony, that vagueness.
"Something would have gone wrong in the kitchen where meals are heated. But I think there was more to it.
Of course. To shut down two engines, doubtless something a bit more complex, perhaps even dire, was afoot.
The pilot had two of the four engines off. Therefore it seemed we were floating. Everyone held his breath. We obviously have done some prayers."
All translation matters considered, this is unhelpful, other than his report that two of the four engines were shut down / off.
"Therefore we were floating."
Actually, Herr Secretary, "therefore, we were still flying!"
(Given two engines were still running). They'd have been floating if all four engines had been secured, and they were landing in, rather than "doing loops" in and about the Adriatic.
Hopefully something in more aviation-like language will be forthcoming to explain this divert.