Hazelnuts as Source of Bioactive Compounds and Health Value Underestimated Food

Hazelnut (HN) has found its way into nontraditional foods due to the recognition of its nutritional and nutraceutical properties. Among nut species, hazelnut plays a major role in human nutrition and health because of its special composition of fat (mainly oleic acid), dietary fibre, vitamins (vitamin E), minerals, phytosterols (mainly β-sitosterol), and antioxidant phenolics. In particular, lipids represent 60% of its dry weight and are mainly represented by triacylglycerols where the main fatty acids are oleic and linoleic acids. Furthermore, HN oil is an exceptional source of specific bioactive compounds as tocopherols, mainly α-tocopherol. Besides a favourable fatty acid profile and high tocopherols content, HNs are also a source of minerals and phytosterols, where potassium and β-sitosterol are the major ones. In addition, the presence of several phenolic antioxidants such as mono- and oligomeric flavan 3-ols has been reported. HNs represent a very interesting food, and their nutritional and health value need to be further evidenced in intervention trials. In addition, the use of HN by-products as new functional ingredient represents an important challenge for the sector and the food industry.