دانلود رایگان مقاله انگلیسی غنی سازی اسید چرب اشباع شده از روغن از طریق ادوات اوره و تغییرات نقش اسید چرب - وایلی 2018

Abstract

The seal oil is a good resource of x-3 polyunsaturated fatty acids (PUFA). Besides being rich in EPA and DHA, it also contains a synergism factor-DPA. Urea adduction is a method that is widely used for the concentration of x-3 PUFA. The aim of this work was to optimize the concentration conditions (urea/oil ratio, crystallization temperature, and time) for EPA, DPA, and DHA by response surface method and study the change rules of fatty acids during the process. The results showed that the optimal conditions for the enrichment was at 2.38:1 urea/FAEE ratio (w/w) upon crystallization at 15 8C for 2.5 hr. The concentration and recovery were 71.35 and 82.31%, respectively, under the optimal conditions. EPA was more easily to be entrapped into the urea than DPA and DHA. SFA (C14:0, C16:0) can be completely removed by urea adduction, while the urea adduction has limited effect on reducing the content of MUFA (C16:1, C18:1, and C20:1). It is necessary to take other methods to remove it.

4 | CONCLUSIONS

The content of EPA, DPA, and DHA in the seal oil was 8.62, 3.99, and 9.24%, respectively. The total content of EPA, DPA, and DHA was 21.85%. The peroxide value (PV), iodine value (IV), acid value (AV), and saponification value (SV) of the seal oil was 4.23 mEq/kg, 116.63 g I2/100g, 0.94 mg KOH/g, and 170.73 mg KOH/g, respectively, which indicated that the oil was in good quality. Therefore, the seal oil is a good resource of x-3 PUFA.

The optimal conditions for the enrichment of EPA, DPA, and DHA by urea adduction were at 2.38:1 urea/FAEE ratio (w/w) upon crystallization at 15 8C for 2.5 hr. The concentration and recovery of EPA, DPA, and DHA were 71.35 and 82.31% under the optimal conditions. The models for the concentration and the recovery of EPA, DPA, and DHA were highly significant at 99% confidence level (p< .01), which indicated that the models were adequate for the process.

PUFA content in the NUCF was greatly improved through urea complexation. DPA and DHA were more difficult to form clathrate compound than EPA since the complicated structure of them. The content of C14:0, C16:0 was greatly decreased through urea complexation. They contributed more of the decrease of SFA and MUFA in the NUCF.

MUFA (mainly C16:1, C18:1, and C20:1) accounted for nearly 20% in the seal oil recovered from the NUCF while the content of SFA was lower than 5%. Hence, it is necessary to take other methods to remove MUFA to obtain higher purity of x-3 PUFA seal oil. Further studies will focus on the remove of MUFA and the separation the EPA, DPA, and DHA and techniques such as molecular distillation, rectification, and preparative chromatography will be applied.