Odors and odorants of the Grain Class
| almond | furfural | 
| bitter almond | 4-acetyltoluene | 
| bread | 2-acetylpyrrole furfural | 
| fat | 2,4-heptadienal | 
| nut | 2-acetylpyrrole 2,4-heptadienal acetylpyrroline | 
| popcorn | methyl pyrazine | 
| roast | acetylpyrroline | 
| sweet | furfural | 
| walnut | 2-acetylpyrrole |