Dear student,
The receptors to taste in humans, called taste buds, are small chemosensory receptor cells. They are sensitive to sweet, salty, bitter, sour and umami (MSG) tastes. There are no separate taste buds for hot food. Hot food actually causes a mild pain in the tongue. Pain fibres (in the tongue) may enhance the sensation of hot foods. These are naked nerve endings (mainly unmyelinated) outside the taste bud and carried via the Trigeminal nerve which gives the sensation.
Regards.