  The color-flavor transformation for the unitary group (Zirnbauer 1996) is
extended to the special unitary group. The resulting partition function is
represented as sum over disconnected sectors characterized by a U(1)-charge.
Application to low energy QCD on a lattice leads to a theory where the inverse
number of colors appears as expansion parameter. We use a saddle point
approximation to estimate the partition function both in the pure mesonic
sector and in the case of a single baryon on a mesonic background.
