Odour thresholds of some organic compounds associated with food flavours

A simple technique for measurement of olfactory thresholds of odorous materials is described. Sensitivity and reproducibility of the method was good, but many precautions must be taken to insure reliability of results. Olfactory thresholds for a number of pure compounds, several of which were identified in potatoes, are presented. In general, sulphur compounds and short-chain unsaturated aldehydes gave the lowest and highest thresholds, respectively. The thresholds of a homologous series of saturated aliphatic aldehydes decreased progressively with increase in chain length from C5 to C10. Similar results were obtained with a series of unsaturated aldehydes. Thresholds of some of the more potent compounds were less than 0.1 of a part per 109 parts of water.