  We study the effect of neutrino trapping in new-born quark stars within a
three-flavor Nambu - Jona-Lasinio (NJL) model with self-consistently calculated
quark masses. The phase diagrams and equations of state for charge neutral
quark matter in beta-equilibrium are presented, with and without trapped
neutrinos. The compact star sequences for different neutrino untrapping
scenarios are investigated and the energy release due to neutrino untrapping is
found to be of the order of 10^53 erg. We find that hot quark stars
characterized, e.g., by an entropy per baryon of 1-2 and a lepton fraction of
0.4, as models for the cores of newborn protoneutron stars, are in the
two-flavor color superconducting (2SC) state. High temperatures and/or neutrino
chemical potentials disfavor configurations with a color-flavor-locked (CFL)
phase. Stable quark star solutions with CFL cores exist only at low
temperatures and neutrino chemical potentials.
