Antepast, n.
Etymology: [Pref. ante- + L. pastus pasture, food. Cf. Repast.]
A foretaste. Antepasts of joy and comforts. Jer. Taylor.
Shades of meaning
Fernald has no entry of its own for antepast; he lists it under anticipation.
Where he writes about it:
Expectation may be either of good or evil; presentiment almost always, apprehension and foreboding always, of evil; anticipation and antepast, commonly of good. — from anticipation