Synthetics
2,4-octadienal has no known odor description.
Mosciano, Gerard P&F 18, No. 4, 51, (1993): Green, fatty, oily, citrus and melon-like
Luebke, William tgsc, (1989): Fatty reminiscent of pear vegetable green
Bedoukian Research: A fatty, fruity, green, citrus odor with peely notes