In "Gulp: Adventures on the Alimentary Canal," Mary Roach highlights that all flavors in food, whether from natural or processed sources, are essentially chemicals. This means that every food item, regardless of its origin or preparation, is made up of unique chemical compounds that contribute to its taste and aroma.

For example, the scent of fresh pineapple comes from specific chemicals like ethyl 3-{methylthio}propanoate, while cucumber's aroma is due to 2E,6Z-Nonadienal. Each fruit has its identifying compounds, revealing that the world of flavors is a complex interplay of various chemicals that define what we perceive as taste.