Enrichment of eicosapentaenoic acid and docosahexaenoic acid in saponified menhaden oil

Abstract

Eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, in free fatty acids (FFA) derived from saponified menhaden oil were concentrated by the solubility differences of FFA-salts in organic solvent. FFA-salts were formed by adding NaOH to a solution containing FFA. A Buchner funnel was used to separate solid phases from liquids containing FFA-salts. FFA that are rich in EPA and DHA can be recovered from the liquid phase by the addition of 12 N HCl. The effects of reaction time, the amount of NaOH, and solvent used on the concentration of EPA and DHA were systematically investigated. With a total volume of 112 mL, made up of 1.85% 15 N NaOH, 88.1% acetone, and 10.0% FFA, a reaction temperature of 30°C, and a reaction time of 1 h, the resulting liquid phase contained 65.4 wt% EPA and DHA, with a corresponding yield of 41.5%. By replacing the acetone with a mixture of 45% acetone and 55% acetonitrile and then storing the liquid phase at −70°C overnight, the content and yield of EPA and DHA in the final liquid phase were 61.4 wt% and 66.2%, respectively.Paper no. J9271 in JAOCS 77, 425-428 (April 2000).KEY WORDS: DHA, EPA, menhaden oil, solubility difference, solvent extraction.Polyunsaturated fatty acids (PUFA) have been the subject of much attention in recent years because of their special physiological functions in human (1). Fish oil is an important natural source for PUFA, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The health-promoting effects of EPA and DHA in human subjects have been reviewed (2,3). Various methods are available for obtaining concentrated EPA and DHA from fish oil, such as urea adducts (4), iodolactonization (5), high-performance liquid chromatography (6), supercritical fluid extraction (7), extraction by silver nitrate (8), and solvent extraction (9). Enzyme methods, including esterification (10), hydrolysis (11), and transesterification (12), have also been employed for the concentration of EPA and DHA. Although enzyme methods usually require more steps, thermal degradation of PUFA can be minimized because of their mild operating temperatures.The solubility of a free fatty acid (FFA)-salt in solvent depends on factors such as the polarity difference between the FFA-salt and the solvent, the chain length, and the number of double bonds in the FFA. In this study, the solubility differences of FFA-salts in organic solvent were employed for the concentration of EPA and DHA in FFA derived from saponified menhaden oil. The effects of reaction time and the amounts of NaOH and solvent used on the concentration of EPA and DHA were studied systematically. MATERIALS AND METHODS Materials.Refined menhaden oil and all fatty acid standards were purchased from Sigma Chemical Co. (St. Louis, MO). All solvents and reagents used were of high-performance liquid chromatographic or American Chemical Society grade. Preparation of FFA. FFA were prepared according to the method described by Haagsma et al. (13) with some modifications. Typically, a 3.7 N NaOH solution was pr...

Comparison of oil yield and quality obtained by different extraction procedures from salmon (Salmo salar) processing byproducts

“…Therefore, if the farmed and wild salmon used in the experiments are from different stages of development the results can be varied. Furthermore, the amount of EPA + DHA in the oil obtained from wild and farmed salmon byproducts was lower than in oils from other fish species like menhaden (26.4%), sardines (27.5%), and tuna (28%) . Nevertheless, the farmed salmon byproducts constitute an abundant source of EPA + DHA.…”

Synthesis of DHA/EPA Ethyl Esters via Lipase-Catalyzed Acidolysis Using Novozym® 435: A Kinetic Study

“…Cobia liver oil was extracted using the homogenization method, as described elsewhere [72]. The extracted crude oil was saponified to obtain free fatty acids (FFAs), as described by Chen and Ju [17]. The DHA+EPA concentrate was prepared from the FFAs by using the acetone fractionation of fatty acid salts method, as described elsewhere [52].…”

“…For health products or medicinal applications, fish oil must use physical, chemical, or enzymatic methods to concentrate n-3 PUFAs. Various concentration methods have been reported, including low temperature solvent crystallization [10], urea complexation [11,12], molecular distillation [13], supercritical fluid extraction [14], high-performance liquid chromatography [15], silver nitrate extraction [16], solvent fractionation [17], and enzymatic methods [18][19][20]. However, concentrated n-3 PUFAs are unstable and difficult to preserve for long periods due to the carboxyl groups enhanced the catalytic effect to form the free radicals by the decomposition of hydroperoxides [21], and therefore must be esterified as triglycerides or ethyl esters to increase storage stability.…”

Aplicação de lipases microbianas na obtenção de concentrados de ácidos graxos poliinsaturados

“…Além disto, na interesterificação química ocorre a redistribuição aleatória dos áci-dos graxos nos TAGs (randomização), dificultando que óleos e gorduras obtidos demonstrem propriedades desejáveis 23 . Os estudos relatados na literatura para extração, concentração e purificação dos AGPI incluem métodos físicos e químicos, tais como complexação com uréia 64,65 , resfriamento por solvente 60 , cristalização fracionada à baixa temperatura 67 , extração com fluido super crítico 68 e extração baseada na solubilidade dos sais de ácidos graxos em diferentes solventes orgânicos 69 . A separação seletiva de AGPI por outros métodos como cromatografia líquida de alta eficiência em fase reversa 70 , coluna de troca iônica usando zeolita 71 , e o método de Corey 72,73 constituíram outras alternativas relatadas em nível experimental.…”