Consumption of food containing cholesterol and saturated fatty acids such as butter can increase serum cholesterol and cause cardiovascular diseases. Therefore many efforts have been done for decreasing these constituents in foods. In this study, hazelnut and walnut powders were added to butter samples in amounts of 0 (not enriched sample), 10, 20 and 30% for evaluation of chemical characteristics (acid value, peroxide value and oxidative stability). Samples were then packed in 2 forms; vacuum and common packed and stored for 90 days at 5°C in refrigerator and were analyzed every 30 days. Adding hazelnut and walnut to butter samples caused significant increase in acid value of samples. Also rising trend of acid value in nut enriched samples was higher during storage. Control samples (without nut) showed higher peroxide value than nut enriched samples. During storage both control and nut enriched samples showed significant increase in peroxide value . Although all of nut enriched samples’ peroxide value were lower than standard limit during storage. Vacuum packed samples also showed lower acid and peroxide value than common packed samples. Adding nuts to butter samples also caused a decrease in oxidative stability of butter samples. This study shows that butter enriched in hazelnut and walnut can be introduced as a new and functional dairy product to consumers, because of its essential fatty acids content.

Keywords: Butter, Walnut, Hazelnut, Oxidative Stability, Acid Value, Peroxide Value