Hazelnut is the nut of the hazel and therefore includes any of the nuts deriving from species of the genus Corylus, especially the nuts of the species Corylus avellana. It is also known as cobnut or filbert nut according to species. A cob is roughly spherical to oval, about 15–25 mm (0.59–0.98 in) long and 10–15 mm (0.39–0.59 in) in diameter, with an outer fibrous husk surrounding a smooth shell. A filbert is more elongated, being about twice as long as its diameter. The nut falls out of the husk when ripe, about 7 to 8 months after pollination. The kernel of the seed is edible and used raw or roasted, or ground into a paste. The seed has a thin, dark brown skin, which is sometimes removed before cooking.
Hazelnuts are used in confectionery to make praline, and also used in combination with chocolate for chocolate truffles. Hazelnut oil, pressed from hazelnuts, is strongly flavoured and used as a cooking oil. Turkey is the world's largest producer of hazelnuts.
Hazelnuts are very high in energy and loaded with numerous health-benefiting nutrients that are essential for optimum health. 100 g nuts carry 628 calories. They are rich in mono-unsaturated fatty acids like oleic as well as essential fatty acid, linoleic acidthat helps lower LDL or bad cholesterol and rise HDL or good cholesterol. Research studies suggest that Mediterranean diet plentiful in monounsaturated fatty acids help to prevent coronary artery disease, and strokes by favoring healthy blood lipid profile.
The nuts are rich in dietary fiber, vitamins, and minerals and packed with numerous health promoting phyto-chemicals. Altogether, they help protect from diseases and cancers.
Hazels are exceptionally rich in folate, which is a unique feature for the nuts. 100 g fresh nuts carry 113 µg; that is, about 28% recommended daily intake of this vitamin. Folate is an important B-complex vitamin that helps prevent megaloblastic anemia,and most importantly, neural tube defects in the newborn. Good news for the expectant mothers!
Hazel nuts are an excellent source of vitamin E; contain about 15 g per 100 g (providing 100% of RDA). Vitamin E is a powerful lipid soluble antioxidant required for maintaining the integrity of cell membrane of mucusa and skin by protecting it from harmful oxygen-free radicals.
The nuts, like in almonds, are free from gluten, and therefore, safe alternative food sources that can be employed in the preparation of gluten-free food formulas for gluten-sensitive, wheat allergic, and celiac disease patients.
Besides being rich in folates, they are packed with many other important B-complex groups of vitamins such as riboflavin, niacin, thiamin, pantothenic acid, and pyridoxine (vitamin B-6).
They are rich source of minerals like manganese, potassium, calcium, copper, iron, magnesium, zinc, and selenium. Copper and manganese are essential co-factors for anti-oxidant enzyme, superoxide dismutase. Iron helps prevent microcytic-anemia. Magnesium and phosphorus are important components of bone metabolism.
Hazelnut oil has nutty aroma and has excellent astringent properties. It helps keep skin well protected from dryness. The oil has also been used in cooking, and as “carrier or base oil” in traditional medicines in massage therapy, aromatherapy, in pharmaceutical and cosmetic industry.