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Showing 2 results for Jafari Naeimi
Volume 17, Issue 98 (April 2020)
Abstract
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.
Volume 18, Issue 117 (November 2021)
Abstract
Ultraviolet radiation was used in the present study to process lemon juice. The designed UV system had five UV-C lamps and irradiation was performed based on the distance of the lamps (10, 20, and 30 cm) from the fluid layer and the circulation time (10, 20, and 30 minutes) of lemon juice in the system. Non-irradiated sample was also considered as a control treatment. The control and irradiated samples were filled in dark polyethylene bottles and stored at ambient temperature for 90 days. Immediately after irradiation and during the storage period, parameters such as pH, titratable acidity, total soluble solids, ascorbic acid content, color indices (L*, a*, and b*), browning index, as well as sensory attributes were evaluated. The pH, acidity, and total soluble solids did not show a definite trend. The results showed that among the color indices, L* decreased significantly, but a* and b* increased significantly during the storage period. The rate of color changes in irradiated samples from a distance of 10 cm was higher than other treatments. Irradiation also significantly reduced the ascorbic acid content of irradiated samples from a distance of 10 cm compared to other samples and control. However, the browning of irradiated samples from 10 cm distance was significantly less than that of irradiated samples from 20 and 30 cm distance. The score of the panelists indicated that irradiation and storage time altered the quality characteristics of lemon juice. The panelistschr('39') scores showed more acceptance of irradiated samples from 20 and 30 cm distance compared to irradiated samples from 10 cm distance. In general, the designed system in this study is not recommended for lemon juice processing due to the destructive effect of UV-C radiation on the content of ascorbic acid.
