Ultrasound-assisted deodorization of sheep tail fat and evaluation of odor intensity using electronic nose and sensorial analysis

Sheep tail fat is a suitable frying oil due to its good flavor and oxidation stability. This oil with its useful fatty acids can to play beneficial effect on consumer health. The refining processes of sheep tail oil, including its deodorization have high importance in the enhancement of the oil quality. Deodorization is a separation process in which a certain amount of the volatile compounds separator gas passes through the hot oil under vacuum condition and removes the volatile and odorous compounds from the oil. In this study, the ultrasound-assisted deodorization of sheep tail fat was carried out and the effects of temperature, time, and ultrasonic power on odor intensity during the deodorization process were investigated using the response surface methodology. The intensity of the odor was assessed by electronic nose and sensorial evaluation. Also, the fatty acid composition was compared before and after the deodorization process. The results of fatty acids profile showed that about 46.72% of sheep tail oil fatty acids were saturated fatty acids (palmitic, stearic, margaric, and myristic) and the rest (53.28%) was unsaturated fatty acids, which the majority of them was oleic acid (39.67%). According to the results of analysis of variance, the composition and kind of the fatty acids before and after the deodorization were close together and the amount of fatty acids changed slightly during the deodorization. Finally, the optimized conditions at the temperature of 162 °C, the time of 110 min and the ultrasonic power of 165 W were determined using electronic nose and sensory evaluation for ultrasound-assisted deodorization of sheep tail oil.