Fractionation of menhaden oil and partially hydrogenated menhaden oil: Characterization of triacylglycerol fractions

Abstract

Menhaden oil (MO) and partially hydrogenated menhaden oil (PHMO) were dry-fractionated and solvent-fractionated from acetone. After conversion to fatty acid methyl esters, the compositional distribution of saturated, monounsaturated, trans, and n-3 polyunsaturated fatty acids (PUFA) in the isolated fractions was determined by gas chromatography. Acetone fractionation of MO at −38°C significantly increased the n-3 PUFA content in the liquid fractions over that of starting MO (P < 0.05). For PHMO, liquid fractions obtained by low-temperature crystallization (−38, −18, and 0°C) from acetone showed significant increases (P < 0.05) in monounsaturated fatty acid (MUFA) content over that of the starting PHMO. For selected MUFA-enriched fractions, reversed-phase high-performance liquid chromatography (HPLC) was used to separate, isolate, and characterize the major triacylglycerol (TAG) molecular species present. Thermal crystallization patterns for these fractions also were determined by differential scanning calorimetry (DSC). The results demonstrated that under the appropriate conditions it is possible to dry-fractionate or solvent-fractionate MO and PHMO into various solid and liquid fractions that are enriched in either saturated, monounsaturated, polyunsaturated, or the n-3 classes of fatty acids. Moreover, characterization of these TAG fractions by reversed-phase HPLC gives insight into the compositional nature of the TAG that are concentrated into the various fractions produced by these fractionation processes. Finally, the DSC crystallization patterns for the fractions in conjunction with their fatty acid compositional data allow for the optimization of the fractionation schemes developed in this study. This information allows for the production of specific TAG fractions from MO and PHMO that are potentially useful as functional lipid products.Paper no. J9723 in JAOCS 78, 297-303 (March 2001).KEY WORDS: Dry fractionation, DSC, menhaden oil, partially hydrogenated menhaden oil, reversed-phase high-performance liquid chromatography, solvent crystallization. EXPERIMENTAL PROCEDURES Materials. MO and 14% boron trifluoride (BF 3 ) in methanol were obtained from Sigma Chemical Company (St. Louis, MO). PHMO was a gift from Omega Protein (Reedville, VA). Acetone, analytical grade, was obtained from Baxter Health Corp. (Muskegon, MI).Fatty acid methyl ester (FAME) analysis. TAG samples (20 mg) were reacted with 2 mL of 14% BF 3 in methanol at 60°C for 15 min. After cooling on ice, 1 mL of saturated NaCl solution and 2 mL of isooctane were added and the mixture was vortexed. The isooctane layer containing the FAME was removed and dried over anhydrous sodium sulfate and analyzed by gas chromatography (GC). A Hewlett-Packard (Agilent,

Characterization of Coconut Oil Fractions Obtained from Solvent Fractionation Using Acetone

“…When comparing the solid fractions with their respective liquid fractions, it was found that the SFC values of all solid fractions were higher than the liquid fractions at all temperatures of measurement. The SFC increase and decrease in the solid and liquid fractions, respectively, from the original fat is what to be expected after fractional crystallization as reported previously 6,10,21 . This is because the solid fraction usually contains higher content of high-melting TAGs than the native fat and the liquid fraction.…”

Synthesis of Fatty Acid Methyl Esters from Jatropha curcas Oil and Its Purification Using Solvent Fractionation

“…So that formation of glyceride crystal would be faster. Solvent (typically acetone) crystallization is used for promoting TAG crystal formation, because TAG at low temperature generally form more stable crystals with solvent than without solvent (Lee et al, 2001). Talbot et al, (2006) reported that an increase in the concentration of solution would be lead to the formation of bigger crystal.…”

Bioseparation of Nutraceuticals Using Supercritical Carbon Dioxide

“…The esters are subsequently fractionated by various methods to obtain higher concentrates of EPA and DHA (Shahidi and Wanasundara 1998) by means of vacuum or short path distillation (Ackman et al 1973;Breivik et al 1997), solvent crystallization (Lee 2003), or urea complexation (Senanayake and Shahidi 2000;Gámez-Meza et al 2003;Zuta et al 2003). These conventional methods often require the use of flammable and toxic organic solvents or elevated process temperatures, which can lead to polymerization and degradation of thermally labile PUFA (Staby and Mollerup 1993;Lee and Foglia 2001). Selective enzymatic hydrolysis of fish oil TGs using fatty acid-specific lipases can be used as well for the separation and concentration of EPA and DHA from other fatty acids present in fish oils (Linder et al 2002;Ramírez Fajardo et al 2006).…”