مقاله انگلیسی رایگان در مورد غنی سازی اسید چرب اشباع شده از روغن – وایلی 2018

The importance of long chain polyunsaturated fatty acids (PUFA) in human nutrition and disease prevention was scientifically recognized many years ago. Research have proved their prominent potential functions in preventing cardiovascular diseases, inflammation, cancer, and neurological disorders (Li et al., 2016; Liu et al., 2013; Simopoulos, 2002; Sun, Pigott, & Herwig, 2010). These health-promoting effects have been linked to the family of x-3 PUFA, mainly to eicosapentenoic acid (EPA, 20:5 x-3) and docosahexaenoic acid (DHA, 22:6 x-3).The traditional source of x-3 PUFA is fish oil. However, it has been reported that fish oil has negative aspects such as typically fishy smell, high content of cholesterol, and poor oxidative ability. Hence, it is of great significance to find new sources of x-3 PUFA (Deng et al., 2011; Renyao et al., 2017; Shen et al., 2012). The seal is one kind of marine mammals, which is widely distributed in countries near the polar region such as Canada, Norway, and Russia. Due to the cold living conditions, the fat layer of the seal is usually thicker than other mammals. Moreover, PUFA account for a reasonable part in the seal oil to keep the liquidity of the cell under the extremely cold environment. Therefore, seal is one of the new materials for the x-3 PUFA products. Besides, the seal oil is also rich in docosapentaenoic acid (DPA), which is seldom found in fish oil. DPA is the intermediate of metabolism and biosynthesis of PUFA and researches have indicated that DPA has different pharmaceutical functions from DHA and EPA. Studies had showed that seal oil was more effective than fish oil in reducing the risk of heart disease and diabetes due to the function of DPA (Conquer, Cheryk, & Chan, 1999; Lin, Wu, & Yue, 2014; Mu, Jin, & Xie, 2016). Some common procedures used to obtain PUFA concentrates are enzymatic purification, argentation silica gel chromatography, low temperature crystallization, supercritical fluid extraction, and urea complexation (Mu et al., 2016). However, only few are suitable for large-scale production (Ratnayake, Olsson, & Matthews, 2010; Senanayake & Shahidi, 2000; Shimada, Sugihara, & Tominaga, 2001). Urea complexation method has many advantages such as low cost, simple equipment, and mild conditions, which is an effective way to concentrate fatty acids with different degrees of unsaturation. The tetragonal conformation of urea in the natural state is converted to the hexagonal crystalline structure by forming a spiral-shaped channel with an average diameter of approximately 5.5–5.8 Å, thus making it possible to entrap smaller-sized linear chain-length molecules (Eaton, Vasanthan, & Shin, 1996; Vasanthan, Shin, & Huang, 1997). With this method, saturated and monounsaturated fatty acids can be easily removed as urea complexation compounds while leaving PUFA in the nonurea complexation fraction (NUCF). The main variables controlling urea complexation are —(i) oil composition, (ii) oil : urea ratio, (iii) temperature of crystallization, and (iv) time of crystallization. The oil composition refers not only to degree of unsaturation but also the class of lipids, that is, triacylglycerols, free fatty acids, or esters.