| ≥1 piece |
As with garlic, onion is high in sulphur compounds, but mostly these are saturated compounds such as the methyl and propyl sulphides, methyl propyl sulphide 66, methyl propyl disulphide 67, methyl propyl trisulphide 68, propyl disulphide 69 and dipropyl sulphide 70. These have less harsh, ‘sweeter’ notes compared to the allyl compounds. Recently two new highly odorous mercaptans were identified in onion6, 3-mercapto-2-methylpentan-1-ol 71, an onion- and leek-like material with an odour threshold of 0.15 ppb, and 3-mercapto-2-methylpentanal 72, more pungent and meaty, with an odour threshold of 0.95 ppb