Flavonoids of grapefruit are better retained than β-carotene in jams. The greatest losses of the analyzed compounds occurred during jam’s storage and not during the production processing. Taking into account the obtained results, microwave heating may be proposed as a good process, better than osmotic dehydration or conventional heating, to obtain a stable jam. This procedure can best fulfill the commitment process time-functional quality of the stored obtained product. Osmotic dehydration would only be recommended if a ready to eat jam is wanted to be obtained