Local media said the Brazilian citizen had arrived on a flight from the city of Belem do Para, in northern Brazil.
It was not immediately clear how police discovered the case.
A second man, suspected of being the recipient of the drug, was detained at the city's train station. The suspects are aged 32 and 40, police say.
The drug seized would have been enough to make 5,000 individual doses of cocaine, police said in a statement (in Portuguese). They did not give an estimate of how much the quantity was worth.
The men could face charges of drug trafficking.
Last month, police in Portugal and Spain seized cocaine hidden inside fresh pineapples that had been transported from South America.