Truffle oil is a modern culinary ingredient added to foods, which is intended to impart the flavor and aroma of truffles to a dish. Most truffle oils are not, in fact, made from actual truffles, but are instead a synthetic product that combines a thioether (2,4-dithiapentane), one of numerous organic aromatics odorants found in real truffles, with an olive oil base. A few more expensive oils are alleged to be made from truffles or the by-products of truffle harvesting and production, though the flavor of truffles is difficult to capture in an oil.
"Their one-dimensional flavor is also changing common understanding of how a truffle should taste," Daniel Patterson complained in a New York Times article.