  We use the Bogoliubov formalism to study both, particles and gravitons
creation at the reheating epoch, after a phase transition from inflation to a
radiation dominated universe. The modes of the inflaton field fluctuations and
the scalar fluctuations of the metric at the end of inflation are obtained by
using a recently introduced formalism related to the Induced Matter theory of
gravity. The interesting result is that the number of created particles is
bigger than $10^{90}$ on cosmological scales. Furthermore, the number of
gravitons are nearly $10^{-17}$ times smaller than the number of created
particles. In both cases, these numbers rapidly increases on cosmological
scales.
