Rancidity n. : The quality or state of being rancid; a rancid scent or flavor, as of old oil.

Example:
What type of Rancidity occurs in vegetable shortenings and how can it be prevented?

Taxonomy
Rancidification, rancidity, foods, free encyclopedia, oxygen, oxidation, natural antioxidants, fats, organisms, flavors, chemical processes, free-radicals, delay, synthetic, water-soluble, fats and oils, growth of bacteria, search.

Defination from the web:
rancidity occurs when the double bonds of an unsaturated fatty acid react chemically with oxygen. Microbial rancidity refers to a process in which micro-organisms such as bacteria use their enzymes, including lipases, to break down chemical structures in the fat. ...