Physical and nutritional properties of four major commercial Turkish hazelnut varieties Feramuz Ozdemir a, * , Ibrahim Akinci b a Faculty of Agriculture, Department of Food Engineering, Akdeniz University, 07070 Antalya, Turkey b Faculty of Agriculture, Department of Agricultural Machinery, Akdeniz University, 07070 Antalya, Turkey Received 26 May 2003; accepted 13 August 2003 Abstract Several physical and nutritional properties of four hazelnut varieties (Palaz, Tombul, Cakildak, and Kara, which are major commercial Turkish hazelnut varieties) were determined and compared in terms of linear dimensions, mass, volume, sphericity, surface area, projected area, true and bulk densities, porosity, repose angle, shell ratio, terminal velocity, rupture force, static co- efficient of friction of hazelnuts and crude protein, oil, crude fiber, energy, ash, dry matter, carbonhydrate and some minerals i.e. K, P, Ca, Mg, Na, Mn, Fe, Zn and Cu contents of samples. All the properties of hazelnuts and kernels that provide useful data to engineers in the design of processing machines were generally found to be statistically different in the four hazelnut varieties. These differences could be attributed to the individual characteristics of these varieties and environmental and growth conditions. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Hazelnut; Corylus avellana L.; Physical and nutritional properties 1. Introduction Nuts are described as dried fruits in seeds, fruit with split hulls or the edible seed kernel of trees. Currently over 4,000,000 t of nuts are commercially produced through the world, of which 700,000 t is hazelnut pro- duction. Hazelnuts are mainly produced in Turkey, Italy, Spain and the USA (Demir, Baucour, Cronim, & Abodayeh, 2003; Ozdemir, Seyhan, et al., 2001; Ozd- emir, Topuz, Dogan, & Karkacier, 1998; Parcerisa, Richardson, Rafecas, Codoni, & Boatella, 1998). Tur- key produces about 550,000 t of hazelnuts annually, which is approximately 80% of the world’s hazelnut production. The other countries producing hazelnuts are Italy with 110,000 t, the USA with 25,000 t and Spain with 18,000 t per year (Demir et al., 2003). Turkey ex- ports 75% of its hazelnuts, and the total export revenue from hazelnuts and hazelnut products is about 1 billion US$ annually. Therefore, hazelnuts have great economic value for Turkey, and for countries which import ha- zelnuts (Akova, 1998). The world tree nut market is segmented into two major categories: the in shell and the shelled tree nuts. The term ‘‘in-shell’’ describes tree nuts that are pro- duced and marketed with the shell intact. Their pro- cessing primarily involves exterior cleaning and preparation for seasonal market. However, the most common form of nuts used in the food-processing sector is the shelled nut. Shelled nuts undergo processes in- cluding blanching, dicing, coating, roasting or grinding to fit product formulation needs, or to add consumer appeal (Demir et al., 2003). It is therefore important to provide accurate scientific data on the relative charac- teristics of varieties of hazelnuts, in order to better de- sign the processing machines. Hazelnuts, due to their organoleptic characteristics, constitute one of the most important raw materials for the pastry and chocolate industry (Fallico, Arena, & Zappala, 2003). Hazelnuts also add flavor and texture to bakery, confectionery, cereal, dairy, salad, entree, sauce and dessert formula- tion. In addition to providing a desirable flavor to dif- ferent food, they have an important role in human nutrition and health due to their protein, oil, vitamin and mineral content. Hazelnuts are rich in both mono- unsaturated and polyunsaturated fatty acids, as well as in vitamin E (Ozdemir, Ackurt, Kaplan, et al., 2001; Journal of Food Engineering 63 (2004) 341–347 www.elsevier.com/locate/jfoodeng * Corresponding author. Tel.: +90-242-310-2434; fax: +90-242-227- 4564. E-mail address: feramuz@akdeniz.edu.tr (F. Ozdemir). 0260-8774/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.jfoodeng.2003.08.006