Another name for propanal, the volatile three-carbon aldehyde. This colorless liquid interconverts readily, reducing to propanol or oxidizing to propanoic acid, and in foods it appears among the carbonyl volatiles that shape aroma at trace levels. Higher concentrations tend to signal oxidative damage or fermentation faults rather than desirable flavor. Chemically it behaves like other short aldehydes: reactive, flammable, and prone to polymerization, so it is handled as an industrial chemical with standard precautions for volatile organics. It is handled in closed systems with ventilation suited to volatile organic chemicals.