  In the simplest scenario for inflation, i. e. in the single-field inflation,
it is presented an inflaton field with properties equivalent to a generalized
Chaplygin gas. Their study is performed using the Hamilton-Jacobi approach to
cosmology. The main results are contrasted with the measurements recently
released by the Planck data, combined with the WMAP large-angle polarization.
If the measurements released by Planck for the scalar spectral index together
with its running are taken into account it is found a value for the
$\alpha$-parameter associated to the generalized Chaplygin gas given by $\alpha
= 0.2578 \pm 0.0009$.
