Presence of Fatty-Acid Ethyl Esters in Krill Oil Dietary Supplements.

Krill oil dietary supplements are increasingly used for their high concentrations of phospholipids (PL), which offer reportedly greater bioavailability of n-3 polyunsaturated fatty acids (PUFA) than those of triacylglycerols or fatty-acid ethyl esters (FAEE) commonly found in fish oils and fish-oil concentrates. This work evaluated the lipid composition of 22 commercial krill oil (CKO) supplements available in the US market, and found ten products (i.e. 45%) contained significant amounts of FAEE, varying from 41% to 75%, by weight. These concentrations of FAEE differed from the minor abundances of FAEE (<3%, by weight) found in manufacturer-supplied krill oil. The potential clinical and regulatory implications for these findings warrant further investigation.

Determination of Iodine Value in Hydrogenated Oils: Comparison of Titration and Gas Chromatography with Flame-Ionization Detection Methodologies.

The United States Food and Drug Administration (FDA) recently issued its final determination that partially hydrogenated oils (PHO) are no longer generally recognized as safe (GRAS) for any use in human food. Consequently, the discrimination between PHO and fully hydrogenated oils (FHO), which is achieved by the iodine value (IV), has become an important regulatory issue. This study compared American Oil Chemists' Society (AOCS) and International Organization for Standardization (ISO) titration and gas chromatography with flame-ionization detection (GC-FID) methodologies for the determination of IV in seven samples of hydrogenated oil, namely coconut, cottonseed (n = 2), palm kernel, palm stearine, and soybean (n = 2) oils. Titrations produced statistically higher IV determinations than those achieved by GC-FID, for all samples except the FH coconut oil. The unsaponifiable matter content of the hydrogenated oils, which varied from 0.15% to 0.47% of total fat, likely contributed modest increases to the IV by titration. Both methodologies were prone to issues at low IV (~4), with titrations showing greater variability, and GC-FID being susceptible to incomplete separation, identification, and quantification of all unsaturated fatty acids. The variability observed with titrations could be minimized by careful execution of the titration protocol. Although both approaches successfully discriminated PHO and FHO in the test materials, at low IV (~4), titration is the most accurate method for determining the IV, and the only approach that has been validated in oils with a very low IV (<1).

Both Dietary Fatty Acids and Those Present in the Cecotrophs Contribute to the Distinctive Chemical Characteristics of New Zealand Rabbit Milk Fat.

The relationship between the fatty acid (FA) profile of cecotrophs and that of the milk fat was evaluated in nine multiparous New Zealand does during the first 12 days of lactation. Milk samples were obtained manually on days 6, 8, 10, and 12 postpartum and cecotrophs and feces were collected on days 7, 9, and 11 postpartum. The FA profiles of feed, milk, cecotrophs, and feces were determined using gas chromatography. The principal FA found in rabbits' milk were 8:0, 10:0, 16:0, 18:1 cis-9, and 18:2 n-6. Bacteria-derived FA found in the milk fat included branched FA from 14 to 16 carbons, and 18:1 trans. Two isomers of conjugated linoleic acid (CLA) were also present, namely cis-9,trans-11 (0.09 ± 0.006 mol%) and trans-10,cis-12 (0.06 ± 0.01 mol%). The content of total FA in the cecotrophs was the 1.10 ± 0.08 mg/100 mg freeze-dried sample, with 2.50 ± 0.83 mol% 18:1 trans-11. Significant correlations between cecotroph and milk FA profiles were found for numerous FA, and those with correlation coefficients greater than 0.90 were 12:0, 14:0, 15:0, 16:0, 18:0, 18:1 trans-6/8, 18:1 trans-9, 18:1 cis-9, 18:2 n-6, 18:3 n-3, 20:1 cis-9, 20:2 n-6, and 22:0. Cecum biohydrogenation processes were evident based on the greater content of saturated FA (p = 0.008) found (54.46 ± 4.37 mol%) in the cecotrophs relative to that in feces (43.08 ± 4.37 mol%). Under conditions of the present study, the milk FA profile was influenced by the FA profile of diet and the cecotrophs consumed by lactating does.

Rapid Prediction of Fatty Acid Content in Marine Oil Omega-3 Dietary Supplements Using a Portable Fourier Transform Infrared (FTIR) Device and Partial Least-Squares Regression (PLSR) Analysis.

Using a portable field device, a Fourier transform infrared spectroscopy (FTIR) and partial least-squares regression (PLSR) method was developed for the rapid (<5 min) prediction of major and minor fatty acid (FA) concentrations in marine oil omega-3 dietary supplements. Calibration models were developed with 174 gravimetrically prepared samples. These models were tested using an independent validation set of dietary supplements. FAs analyzed included eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); the sums of saturated, branched-chain, and monounsaturated FAs; and n-6, n-4, n-3, n-1, and trans polyunsaturated FA. The spectral ranges 650-1500 or 650-1500 and 2800-3050 cm-1 provided reliable predictions for FA components in 34 neat oil products: standard error of prediction, 0.73-1.58%; residual predictive deviation, 6.41-12.6. This simple, nondestructive quantitative method is a rapid screening tool and a time and cost-saving alternative to gas chromatography for verifying label declarations and in quality control.