  We study the consequences of antineutrino trapping in hot quark matter for
quark star configurations with possible diquark condensation. Due to the
conditions of charge neutrality and beta-equilibrium the flavor asymmetry
increases with the number density of trapped antineutrinos such that above a
critical value of the antineutrino chemical potential of 30 MeV diquark
condensation is inhibited. When the quark star cools a two-phase structure
occurs: a superconducting quark matter core surrounded by a shell of normal
quark matter. Below the critical temperature of about 1 MeV, the antineutrino
mean free path becomes larger than the thickness of the normal quark matter
shell so that they get untrapped within a sudden process. By comparing the
masses of configurations with the same baryon number we estimate that the
release of energy due to the antineutrino untrapping transition can be in the
range of 10^{51} to 10^{52} erg.
