Journal of the American Oil Chemists' Society

A method is described for the determination of unsaponifiable matter in fatty acids and mixtures of fatty and rosin acids by the use of a mixed bed ion-exchange resin.

A study of the new phase, kettle wax, in the system sodium laurate, sodium chloride and water has been carried out using analytical and visual methods. The lower boundaries of kettle wax and its equilibria were established and when plotted occupy a highly dominant island region on the phase diagram. It occupies a portion between 60 and 70 wt. % soap and about 3 and 7 wt. % of salt. The effects of temperature on kettle wax in this system have also been studied. It was found that kettle wax existed above 75°C. and below 215°C. and has the same type of equilibria with lye throughout this temperature range. In the system sodium laurate, sodium chloride and water, curd is not formed, even by saturating the lye with salt at 90°C. Hence graining out results only in the formation of kettle wax and lye.

Incompatibilities between fats limit the use of modified milk fat in confectionery applications. To further enhance the use of milk-fat fractions in chocolates and compound coatings, a better understanding of mixed crystallization effects between lipids is required. Recent work documents that highmelting fractions incorporated into chocolates drastically reduce bloom formation and cause less softening than anhydrous milk fat. Isosolids diagrams for mixtures of cocoa butter and milk-fat fractions show that softening occurs due to both dilution effects and a slight eutectic formation. Incorporation of milk-fat fractions into palm kernel oil-based coatings shows some differences with results in chocolates. Milk fat and its fractions cause significant bloom formation in these coatings, as compared to the control, and cause significant softening. However, both milk fat and milk-fat fractions are fully compatible with palm kernel oil, based on isosolids diagrams. Softening occurs only because of dilution effects, rather than eutectic formation. Further work is necessary to understand the effects of milk-fat fractions on bloom formation in compound coatings.

The purpose of the present study was to reduce the cost and increase the efficiency of biodiesel production by reactive extraction (in situ) of Jatropha seeds. Oil from the seeds was extracted and reacted in a single step. Experimental studies have been carried out to maximize the yield of biodiesel by varying the reaction parameters viz. seed size (<0.85 mm to >2.46 mm), seed/solvent ratio (w/w) (1:2.6–1:7.8) and catalyst concentration (0.05–0.1 M). Under the optimized conditions: seed size (>2.46 mm), seed/solvent ratio (w/w) (1:7.8), catalyst concentration (0.1 M) and reaction time 1 h, approximately 98% conversion to biodiesel was achieved meeting International (ASTM) as well as National (BIS) specifications. The results were supported by HPLC analysis.

The glyceride compositions of seven animals and seven vegetable fats have been determined by GLC analysis of the oxidized esterified glycerides as described in an earlier paper in this series. The compositions determined are compared with those calculated from lipase hydrolysis data according to the method of VanderWal. Good agreement was found between the calculated and determined compositions for the majority of the 14 fats. The exceptions were human fat and the more satu-rated vegetable fats, palm oil and cocoa butter, where some discrepancies occurred.

Lipid oxidation is one of the major causes of oil deterioration causing off-flavors and consumer rejection. Fast, easy, and dependable assays for predicting lipid oxidation rates in foods are important for shelf-life prediction. In this study, an electron paramagnetic resonance (EPR) spin-trapping technique with N-tert-butyl-α-phenylnitrone (PBN) was tested to determine the lag phase of lipid oxidation in stripped soybean oil (SSO), SSO with added α-tocopherol, and commercial soybean, canola and corn oils. EPR intensity of spin-trapped products from SSO correlated well with lipid hydroperoxides formation for samples stored at 37 and 55 °C respectively. When the antioxidant α-tocopherol was added, the EPR signal intensity of oil samples increased—indicating sample deterioration—after 50–65% of α-tocopherol was consumed. When using the EPR method with commercial soybean, canola or corn oil stored at 55 °C, there was a poor relationship between EPR intensity and lipid hydroperoxides lag phases. However, a linear correlation was found between EPR signal intensity and hexanal formation. For example, EPR signal intensity lag phases were 5, 13 and 27 days for soybean, canola and corn oils, respectively which was similar to the hexanal lag phases of 5, 13 and 25 days for the same oils. The EPR spin-trapping assay method has several advantages over headspace hexanal measurements, especially with regard to easier sample handling and shorter analysis times.

The biosynthetic pathway of two bicyclic FA, 12∶17, 13∶17-diepoxy-9(Z)-octadecenoic acid (DEOA) and 7-hydroxy-12∶17, 13∶17-diepoxy-9(Z)-octadecenoic acid (hDEOA), by Clavibacter sp. ALA2 was investigated. When cultivated with linoleic acid as a substrate, the strain produced 12,13,17-trihydroxy-9(Z)-octadecenoic acid (THOA), DEOA, and hDEOA as well as other FA. To clarify the synthetic route to these bicyclic FA, the strain was cultivated with purified THOA as a starting substrate. THOA was consumed almost completely by the strain with sequential generation of DEOA and hDEOA. Moreover, the strain produced hDEOA when cultivated with purified DEOA. Therefore, it was confirmed that THOA was a precursor of these bicyclic FA and that hDEOA was generated from DEOA. Based on our previously reported result that linoleic acid is first converted to 12,13-dihydroxy-9(Z)-octadecenoic acid (DHOA) and the present results, the overall biosynthetic pathway for the diepoxy bicyclic FA from linoleic acid was postulated as: linoleic acid→DHOA→THOA→DEOA→hDEOA.

The influence of temperature on the fatty acid composition of the oils from conventional and high oleic sunflower genotypes grown in tropical regions was evaluated under various environmental conditions in Brazil (from 0° S to 23° S). The amounts of the oleic, linoleic, palmitic and stearic fatty acids from the sunflower oil were determined using gas chromatography (GC). The environment exhibited little influence on the amounts of oleic and linoleic fatty acids in high oleic genotypes of sunflower. In conventional genotypes, there was broad variation in the average amounts of these two fatty acids, mainly as a function of the minimum temperature. Depending on the temperature, especially during the maturation of the seeds, the amount of oleic acid in the oil of conventional sunflower genotypes could exceed 70 %. Higher temperatures led to average increases of up to 35 % for this fatty acid. Although the minimum temperature had the strongest effect on the fatty acid composition, locations at the same latitude with different minimum temperatures displayed similar values for both oleic acid and linoleic acid. Furthermore, minimum temperature had little influence on the amounts of palmitic and stearic fatty acids in the oil.

Nonvolatilealpha-branched carboxylic acids and esters have been prepared by a free radical reaction. Various esters of the reaction products of hexadecanoic and octadecanoic acids with the terminal olefins, octene, decene, and dodecene have been synthesized. Fractional crystallization from acetone is a useful method for preparing these compounds in a highly purified state. Mass spectra confirm that branching is found exclusively at thealpha- or 2-position.