Hexanal

An aldehyde-group aroma compound — also called caproaldehyde — giving many fresh foods a green, fruity scent. It additionally emerges when fatty acids oxidize in fat-rich foods, where it marks the onset of rancidity: rising hexanal levels in oils, snacks, and fatty products tell analysts that oxidation is progressing. This dual role — desirable fresh note versus spoilage marker — makes it one of the most closely watched volatiles in flavour and shelf-life analysis. Flavour laboratories monitor its concentration through storage trials, and processors use it to judge the oxidative stability of frying oils, snack coatings, and fat-rich ingredients.