IPA: /ˌæsɪˈdʒʊleɪʃən/
KK: /ˌæsɪˈdʒʊleɪʃən/
The process of making something more acidic, often by adding an acid to it.
The acidulation of the solution improved its flavor.
Acidulation is formed from "acid" (from Latin "acidus", meaning sour) and "-ation" (a suffix used to form nouns indicating an action or process). The word refers to the process of making something sour or acidic.
Think of 'acid' meaning sour, and '-ation' indicating a process — so acidulation is the process of making something sour.