The practice of encapsulating a functional material in a thermally stable porous material displays great potential in preventing decomposition during high-temperature processing. In this study, caffeine encapsulated in zeolite was coated with TiO 2 to withstand high-temperature melt extrusion with poly(ethylene terephthalate) (PET). Two coating processes were trialed: in situ encapsulation and coating where TiO 2 precursor was added to zeolite/caffeine solution; and ex situ coating in which pre prepared zeolite/caffeine capsules were added to the TiO 2 precursor for coating. The TiO 2 -coated nanocomposites were melt-extruded with PET at 285 °C. Residual amounts of caffeine confirmed the shielding effect of the TiO 2 coating during the high-temperature melt extrusion. The in situ TiO 2 coating process was more effective than the ex situ process. © 2019 The Society of Powder Technology Japan