A process which thermomechanically transforms raw materials through short-time and high-temperature conditions under pressure. In rice fortification, dough made of rice flour, vitamin/mineral mix, and water is passed through a single- or twin-screw extruder that cuts it into grain-like structures that resemble rice grains. Hot extrusion involves relatively high temperatures (70 - 110°C), obtained by preconditioning and/or heat transfer through steam-heated barrel jackets. It results in fully or partially precooked simulated rice-like grains that have a similar appearance (sheen and transparency) to unfortified rice kernels.
WHO (2018). "Guideline: fortification of rice with vitamins and minerals as a public health strategy."