April 10 (Reuters) - Barry Callebaut, the world's biggest chocolate maker, reported lower than expected half-year operating profit on Wednesday, hit by one-off expenses caused by its transformation plan.

The Swiss-based company said its earnings before interest and tax fell 40% in local currencies to 178 million Swiss francs ($197 million) on a reported basis in the six months to the end of February, compared with 266 million francs expected by analysts in a company-provided consensus. ($1 = 0.9036 Swiss francs) (Reporting by Paolo Laudani and Mateusz Dobrzyniewski; editing by Milla Nissi)