Sh. Emami - Department of Food Science and Technology, College of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.
S. Azadmard-Damirchi - Department of Food Science and Technology, University of Tabriz, Tabriz, Iran
J. Hesari - Department of Food Science and Technology, College of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.
S. H. Peighambardoust - Department of Food Science and Technology, College of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.
Y. Ramezani - Department of Animal Science, College of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.
M. Nemati - Department of Pharmacognosy and Hydrology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Islamic Republic of Iran.
M. Esmaili - Department of Food Science and Technology, Faculty of Agriculture, University of Urmia, Urmia, slamic Republic of Iran.
S. A. Rafat - Department of Animal Science, College of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.

World consumption of butter has declined over the last decades partly due to its physical limitations and partly due to its poor nutritionalproperties. In this study, the effect of hazelnut addition on the properties of butter, was evaluated taking into account that hazelnut is a source of unsaturated fatty acids and antioxidants. Powdered hazelnut was added to butter at ۳ levels (۱۰, ۲۰ and ۳۰ percent w/w). The butter samples were then kept in refrigerator for ۴ weeks. The acid and peroxide values, oxidative stability, fatty acid profile, tocopherol content as well as sensory characteristics of hazelnut added butter samples were determined and compared with those of control as during cold storage. Results revealed that hazelnut fortified butter samples bore higher acid values vs. lower peroxide value, as well as oxidative stability values than the control samples. Both acid values, and peroxide values increased in all the samples throughout storage. The concentration of unsaturated fatty acids, including essential fatty acids were recorded as significantly higher (P<­ ۰.۰۵) in the fortified butter samples. The contents of α- and γ,β-tocopherol were also higher for the fortified samples, however, their levels especially the level of α-tocopherol, decreased during storage. Sensory evaluation showed no significant difference (P­>­ ۰.۰۵) between fortified vs. control samples in terms of either the overall acceptance or any undesirable flavor characteristics. This study introduces a new functional dairy product that can be a step forward towards the modification of butter nutritional drawbacks through an increase in its essential fatty acids as well as antioxidant constituents.

Butter, Fatty acids, Hazelnut, Sensory characteristics, Tocopherol