  Physical equivalence between different conformal frames in scalar-tensor
theory of gravity is a known fact. However, assuming that matter minimally
couples to the metric of a particular frame, which we call the matter Jordan
frame, the matter point of view of the universe may vary from frame to frame.
Thus, there is a clear distinction between gravitational sector (curvature and
scalar field) and matter sector. In this paper, focusing on a simple power-law
inflation model in the Einstein frame, two examples are considered; a
super-inflationary and a bouncing universe Jordan frames. Then we consider a
spectator curvaton minimally coupled to a Jordan frame, and compute its
contribution to the curvature perturbation power spectrum. In these specific
examples, we find a blue tilt at short scales for the super-inflationary case,
and a blue tilt at large scales for the bouncing case.
