  The ground state, zero-temperature magnetization process, critical behaviour
and isothermal entropy change of the mixed-spin Ising model on a decorated
triangular lattice in a magnetic field are exactly studied after performing the
generalized decoration-iteration mapping transformation. It is shown that both
the inverse and conventional magnetocaloric effect can be found near the
absolute zero temperature. The former phenomenon can be found in a vicinity of
the discontinuous phase transitions and their crossing, while the latter one
occurs in some paramagnetic phases due to a spin frustration to be present at
zero magnetic field. The inverse magnetocaloric effect can also be detected
slightly above continuous phase transitions following the power-law dependence
$|-\Delta{\cal S}_{iso}^{min}|\propto h^n$, where $n$ depends basically on the
ground-state spin ordering.
