Synonyms for Zest (same or very similar meaning)
WordNet sense 1 (vigorous and enthusiastic enjoyment):
gusto, relish, zestfulnessWordNet sense 2 (a tart spicy quality):
piquancy, tang, piquance, tanginess, tang, piquantnessWordNet sense 3 (add herbs or spices to):
spice, spice upFrom the ODE community, based on WordNetadd/edit