Pumpkin seed oil (Kernöl or Kürbiskernöl in German, bučno olje in Slovenian, bučino ulje or bundevino ulje in Serbian and Croatian, and tökmag-olaj in Hungarian), a culinary specialty of south eastern Austria (Styria), eastern Slovenia (Styria and Prekmurje), north western Croatia (esp. Međimurje), adjacent regions of Hungary, is a European Union Protected Designation of Origin (PDO) product.
Today the oil is an important export commodity of Austrian and Slovenian parts of Styria. It is made by pressing roasted, hulled pumpkin seeds (pepitas), from a local variety of pumpkin, the "Styrian oil pumpkin" (Cucurbita pepo var. styriaca, also known as var. oleifera). It has been produced and used in Styria's southern parts at least since the 18th century. The earliest confirmed record of oil pumpkin seeds in Styria (from the estate of a farmer in Gleinstätten) dates to February 18, 1697.
The viscous oil is light to very dark green to dark red in colour depending on the thickness of the observed sample. The oil appears green in thin layer and red in thick layer. Such optical phenomenon is called dichromatism. Pumpkin oil is one of the substances with strongest dichromatism. Its Kreft's dichromaticity index is -44. Used together with yoghurt, the colour turns to bright green and is sometimes referred to as "green-gold".
Pumpkin seed oil has an intense nutty taste and is rich in polyunsaturated fatty acids. Browned oil has a bitter taste. Pumpkin seed oil serves as a salad dressing when combined with honey or olive oil. The typical Styrian dressing consists of pumpkin seed oil and cider vinegar. But the oil is also used for desserts, giving ordinary vanilla ice cream an exquisite nutty taste. It is considered a real delicacy in Austria, and few drops are added to pumpkin soup and other local plates, including, as mentioned, vanilla ice cream. Using it as a cooking oil, however, destroys its essential fatty acids.