The hazelnut is the fruit of the hazelnut tree. A plant that has been cultivated by man since ancient times. After the almonds they are the fruit with the highest vitamin E content and a source of phytosterols, a group of substances considered important for the prevention of cardiovascular diseases. The hazelnut is often counted among the dried fruits and initially has a greenish color that turns light brown as it ripens. The fruit is partially covered by an irregular leaf-like shell. The seeds inside, which are rich in lipids, proteins and water, are edible and have a crunchy texture and can be eaten fresh or dried. Their composition makes the hazelnut a high-calorie food. It is mainly used in industrial processing, as it blends well with milk and dark chocolate, in the confectionery industry for the production of nougat, cakes and creams. In German-speaking countries, the hazelnut is used in the form of flour for the preparation of a typical cake. For most uses, it is first roasted.Its oil, which is used by the cosmetics industry or for food, is also much sought after, but is very expensive for the small quantities produced.