production of yoghurt fordified with walnut powder

milk and dairy products are in diet almost every day. milk fat contains 70% of saturated fatty acids which can cause an increase in total and low-density lipoprotein cholesterol, and the risk of cardiovascular diseases. therefor, modification of fat composition at dairy products such as yoghurt seems necessary. walnut has high amount of essential fatty acids, anti oxidants and other beneficial components. in this study, ground walnut is added to yoghurt at level of 0 (control sample), 3, 6 and 9% and their texture properties (synersis and viscosity), sensory, fatty acids profile and dry matter were analysed every week for 4 weeks during storage. results showed that fortification of yoghurt samples with ground walnut and storage had significant effects ( ) on synersis, viscosity, fatty acids profile and dry matter. control sample had the highest synersis and the lowest viscosity and dry matter among samples. by adding ground walnut to yoghurt samples, the amount of saturated fatty acids decreased and the amount of unsaturated fatty acids increased. major fatty acids of yoghurt incorporating ground walnut were linoleic acid, oleic acid, linolenic acid, palmitic acid and stearic acid, respectively. the highest final score in sensory evaluation in 1, 14 and 28 days of storage time were for yoghurt samples with 9% of gorund walnut, yoghurt with 6 and 3% of ground walnut and yoghurt with 3% of gorund walnut, respectively. results of this study showed that adding ground walnut modifies yoghurt fat composition, forify it with essential fatty acids and also has good effect on its texure properties.