Jam processing and storage effects on β-carotene and flavonoids content in grapefruit

► Jam processing and storage effect on grapefruit phytochemicals has been evaluated. ► Osmotic dehydration, microwave and conventional heating were used to obtain jam. ► Carotene and major flavonoids were analyzed by HPLC. ► The analyzed compounds loss was greater during storage than during processing. ► Microwave heating may be proposed as the best process to obtain a stable jam.