In 1974, he went to what was now the Democratic Republic of the Congo (DRC); the government of Mobutu Sese Seko contracted him as an investigator and he offered technical assistance with small rural producers.

Claudio used a canoe that took two weeks to reach Lomela, but planned to build a boat, which he named the DB,1 to reduce travel time.

Through various tests he found that the bitterness was caused by processing failures, moisture storage and the country's equatorial heat.

[3] He then bought an abandoned cocoa plantation of 120 hectares (300 acres) in Terreiro Velho (Old Farm) next to Novo Estrela on the island of Príncipe.

[3] Corallo taught classes in agrarian science courses at the Higher Polytechnic Institute (Instituto Superior Politécnico de São Tomé e Príncipe (ISP)) which became a campus of the University of São Tomé and Príncipe (USTP) and at the (Centro de Aperfeiçoamento Técnico Agropecuário (CATAP)) (now the Center for Studies for Development, also a campus of the university.)