Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
gustātĭo, ōnis, f. [id.; a first tasting of food; hence], the first light dish of a Roman meal, an antepast, whet: jussi discubuimus, et gustatione mirifica initiati vino etiam Falerno inundamur, Petr. 21, 6; 31, 8.