Rancidity

The development of unpleasant odors and flavors in fats, oils, and fat-containing foods through oxidation or hydrolysis. Oxidative rancidity arises when unsaturated fatty acids react with oxygen in radical chain reactions, producing aldehydes and ketones with painty, cardboard-like notes, while hydrolytic rancidity releases free fatty acids with soapy flavors, often through lipase activity. Warmth, light, metals, and air accelerate the process. Processors combat rancidity with antioxidants, oxygen-barrier packaging, nitrogen flushing, and cold storage, and analysts track peroxide and anisidine values to predict shelf life before sensory failure.