Metabolism of triacylglycerol species during seed germination in fatty acid sunflower (Helianthus annuus) mutants

Sunflower mutant lines with high saturated fatty acid content (palmitic or stearic) in the oil have a completely different set of triacylglycerols (TAG), some of which were not found in standard sunflowers. For optimum seed germination, all of these new TAG species must be effectively catabolized. The behavior of the TAG composition during germination in cotyledons of all these mutant lines showed two different phases: an initial phase (between 0 and 2 days after sowing) with a higher catalytic activity and a preference for TAG containing at least two oleic acid molecules and a second phase with lower TAG degradation rate and a low preference for TAG containing two saturated fatty acids usually accompanied by linoleic acid. Despite the elevated content of saturated fatty acids in some TAG species, the total TAG degradation rate and germination process were similar in these lines, suggesting that sunflower seed lipases do not show a marked preference for any TAG species.     

Lipase-catalyzed acidolysis of tripalmitin with hazelnut oil fatty acids and stearic acid to produce human milk fat substitutes

Structured lipids (SLs) containing palmitic, oleic, stearic, and linoleic acids, resembling human milk fat (HMF), were synthesized by enzymatic acidolysis reactions between tripalmitin, hazelnut oil fatty acids, and stearic acid. Commercially immobilized sn-1,3-specific lipase, Lipozyme RM IM, obtained from Rhizomucor miehei was used as the biocatalyst for the enzymatic acidolysis reactions. The effects of substrate molar ratio, reaction temperature, and reaction time on the incorporation of stearic and oleic acids were investigated. The acidolysis reactions were performed by incubating 1:1.5:0.5, 1:3:0.75, 1:6:1, 1:9:1.25, and 1:12:1.5 substrate molar ratios of tripalmitin/hazelnut oil fatty acids/stearic acid in 3 mL of n-hexane at 55, 60, and 65 degrees C using 10% (total weight of substrates) of Lipozyme RM IM for 3, 6, 12, and 24 h. The fatty acid composition of reaction products was analyzed by gas-liquid chromatography (GLC). The fatty acids at the sn-2 position were identified after pancreatic lipase hydrolysis and GLC analysis. The results showed that the highest C18:1 incorporation (47.1%) and highest C18:1/C16:0 ratio were obtained at 65 degrees C and 24 h of incubation with the highest substrate molar ratio of 1:12:1.5. The highest incorporation of stearic acid was achieved at a 1:3:0.75 substrate molar ratio at 60 degrees C and 24 h. For both oleic and stearic acids, the incorporation level increased with reaction time. The SLs produced in this study have potential use in infant formulas.     

Oils from improved high stearic acid sunflower seeds

Seed oils from new recombinant high-stearic sunflower lines (Helianthus annuus L.) have been characterized. These new lines were generated by crossing high stearic acid lines between themselves or by crossing them with standard and high-oleic sunflower lines. Of the novel lines generated, the lines CAS-29 and CAS-30 are on a standard background and contain up to 34.5% of stearic acid. In contrast, CAS-15 and CAS-33 are on a high oleic acid background and contain only 24.9 and 17.4% of stearic acid, respectively. The stearic acid contents of lines CAS-19 and CAS-20 are 10.0 and 21.5%, respectively, and they have only one of the two genes that control the high stearic acid trait. In accordance with their vegetable origin, these lines have a low percentage of stearic acid in the sn-2 position of the TAGs, from 0.6 to 2.1%. The amount of disaturated TAGs increases with the stearic acid content, from 1.8% in the standard line to between 5.1% in CAS-20 and 38.5% in CAS-29. There was also a concomitant reduction in triunsaturated TAGs, which were reduced to levels as low as 8.4% in CAS-29, as opposed to the 67.9% that they constitute in the standard line RHA-274. The asymmetrical distribution of the saturated fatty acids between the sn-1 and sn-3 TAG positions ranges from 0.26 to 0.36, being lower in those lines with higher oleic acid content.     

Influence of harvest date and crop yield on the fatty acid composition of virgin olive oils from cv. Picual

In this study was analyzed the effect of crop year and harvesting time on the fatty acid composition of cv. Picual virgin olive oil. The study was carried out during the fruit ripening period for three crop seasons. The mean fatty acid composition of Picual oils was determined. The oils contained palmitic acid (11.9%), oleic acid (79.3%), and linoleic acid (2.95%). The content of palmitic acid and saturated fatty acids decreased during fruit ripening while oleic and linoleic acids increased. The amount of stearic and linolenic acids decreased. The amount of saturated acids, palmitic and stearic, and the polyunsaturated acids linoleic and linolenic was dependent on the time of harvest, whereas the amount of oleic acid varied with the crop year. The differences observed between crop years for both palmitic and linoleic acid may be explained by the differences in the temperature during oil biosynthesis and by the amount of summer rainfall for oleic acid content. A significant relationship was observed between the MUFA/PUFA ratio and the oxidative stability measured by the Rancimat method.     

Assessment of oil content and fatty acid composition variability in two economically important Hibiscus species

The Hibiscus genus encompasses more than 300 species, but kenaf (Hibiscus cannabinus L.) and roselle (Hibiscus sabdariffa L.) are the two most economically important species within the genus. Seeds from these two Hibiscus species contain a relatively high amount of oil with two unusual fatty acids: dihydrosterculic and vernolic acids. The fatty acid composition in the oil can directly affect oil quality and its utilization. However, the variability in oil content and fatty acid composition for these two species is unclear. For these two species, 329 available accessions were acquired from the USDA germplasm collection. Their oil content and fatty acid composition were determined by nuclear magnetic resonance (NMR) and gas chromatography (GC), respectively. Using NMR and GC analyses, we found that Hibiscus seeds on average contained 18% oil and seed oil was composed of six major fatty acids (each >1%) and seven minor fatty acids (each <1%). Hibiscus cannabinus seeds contained significantly higher amounts of oil (18.14%), palmitic (20.75%), oleic (28.91%), vernolic acids (VA, 4.16%), and significantly lower amounts of stearic (3.96%), linoleic (39.49%), and dihydrosterculic acids (DHSA, 1.08%) than H. sabdariffa seeds (17.35%, 18.52%, 25.16%, 3.52%, 4.31%, 44.72%, and 1.57%, respectively). For edible oils, a higher oleic/linoleic (O/L) ratio and lower level of DHSA are preferred, and for industrial oils a high level of VA is preferred. Our results indicate that seeds from H. cannabinus may be of higher quality than H. sabdariffa seeds for these reasons. Significant variability in oil content and major fatty acids was also detected within both species. The variability in oil content and fatty acid composition revealed from this study will be useful for exploring seed utilization and developing new cultivars in these Hibiscus species.     

Oil and tocopherol content and composition of pumpkin seed oil in 12 cultivars

Twelve pumpkin cultivars (Cucurbita maxima D.), cultivated in Iowa, were studied for their seed oil content, fatty acid composition, and tocopherol content. Oil content ranged from 10.9 to 30.9%. Total unsaturated fatty acid content ranged from 73.1 to 80.5%. The predominant fatty acids present were linoleic, oleic, palmitic, and stearic. Significant differences were observed among the cultivars for stearic, oleic, linoleic, and gadoleic acid content of oil. Low linolenic acid levels were observed (<1%). The tocopherol content of the oils ranged from 27.1 to 75.1 microg/g of oil for alpha-tocopherol, from 74.9 to 492.8 microg/g for gamma-tocopherol, and from 35.3 to 1109.7 microg/g for delta-tocopherol. The study showed potential for pumpkin seed oil from all 12 cultivars to have high oxidative stability that would be suitable for food and industrial applications, as well as high unsaturation and tocopherol content that could potentially improve the nutrition of human diets.     

Fatty acid, triacylglycerol, phytosterol, and tocopherol variations in kernel oil of Malatya apricots from Turkey

The fatty acid, sn-2 fatty acid, triacyglycerol (TAG), tocopherol, and phytosterol compositions of kernel oils obtained from nine apricot varieties grown in the Malatya region of Turkey were determined ( P<0.05). The names of the apricot varieties were Alyanak (ALY), Cataloglu (CAT), C?loglu (COL), Hacihaliloglu (HAC), Hacikiz (HKI), Hasanbey (HSB), Kabaasi (KAB), Soganci (SOG), and Tokaloglu (TOK). The total oil contents of apricot kernels ranged from 40.23 to 53.19%. Oleic acid contributed 70.83% to the total fatty acids, followed by linoleic (21.96%), palmitic (4.92%), and stearic (1.21%) acids. The s n-2 position is mainly occupied with oleic acid (63.54%), linoleic acid (35.0%), and palmitic acid (0.96%). Eight TAG species were identified: LLL, OLL, PLL, OOL+POL, OOO+POO, and SOO (where P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl), among which mainly OOO+POO contributed to 48.64% of the total, followed by OOL+POL at 32.63% and OLL at 14.33%. Four tocopherol and six phytosterol isomers were identified and quantified; among these, gamma-tocopherol (475.11 mg/kg of oil) and beta-sitosterol (273.67 mg/100 g of oil) were predominant. Principal component analysis (PCA) was applied to the data from lipid components of apricot kernel oil in order to explore the distribution of the apricot variety according to their kernel's lipid components. PCA separated some varieties including ALY, COL, KAB, CAT, SOG, and HSB in one group and varieties TOK, HAC, and HKI in another group based on their lipid components of apricot kernel oil. So, in the present study, PCA was found to be a powerful tool for classification of the samples.     

Variability of fat content and fatty acids profiles in seeds of a Polish white lupin (<Emphasis Type="Italic">Lupinus albus</Emphasis> L.) collection

The paper assess the variability of fat content and fatty acids profiles in seeds of a white lupin (Lupinus albus L.) domestic collection. The initial material comprised 371 accessions originated from 30 countries of Europe, Asia, Africa, North- and South America and Australia. According to data given by accession donors the material is divided into four classes of origin: wild lines, landraces, lines created by man and cultivars. Variability of fat content and fatty acids composition were estimated in seeds of each accession. The average fat content for analyzed collection is 9.81%. The broadest range of fat content was noticed for landraces and cultivars as compared to narrowest represented by lines created by man. Fat content ranged from 6.9% (induced mutant Wt 95497) to 14.1% (Polish cultivar Wt 95420 and the landrace Wt 95212 from Jordan). From a dietetic point of view, oil quality is more important than oil quantity in lupin seeds. On average the fatty acid (FA) in examined accessions ranked in following order of abundance: oleic acid (C_18:1) > linoleic acid (C_18:2) > linolenic acid (C_18:3) > palmitic acid (C_16:0) > eicosenoic acid (C_20:1) > stearic acid (C_18:0) ≈ erucic acid (C_22:1). In respect to unsaturated fatty acid (UFA), monounsaturated oleic acid in each of estimated classes of accessions was predominant and most abundant (55.7%) in broad range of minimum–maximum values from 41.2 to 66.2%. The second examined monounsaturated fatty acid was erucic acid (1.74%) found in seeds of almost all studied accessions. An exception were four accessions defined similarly to rapeseeds as “zero erucic” forms. In seeds of few accessions a content of erucic acid exceeded 3%. Among polyunsaturated fatty acids linoleic FA (ω?6) dominated followed by linolenic FA (ω?3). Both FA were in the range 13.7–33.2% and 5.6–12.8% with mean values on the level 19.6 and 10.1%, respectively. As a consequence, the examined white lupin seeds showed a very favourable ω?3/ω?6 FA ratio (0.51), ranging from 0.21 to 0.87, much higher than that of most vegetable oils. Fat content was positively correlated with stearic and oleic fatty acids and negatively with palmitic, linoleic, linolenic and erucic acid.     

Oil goldenberry (Physalis peruviana L.)

Whole berries, seeds, and pulp/peel of goldenberry (Physalis peruviana L.) were compared in terms of fatty acids, lipid classes, triacylglyerols, phytosterols, fat-soluble vitamins, and beta-carotene. The total lipid contents in the whole berries, seeds, and seedless parts were 2.0, 1.8, and 0.2% (on a fresh weight basis), respectively. Linoleic acid was the dominating fatty acid followed by oleic acid as the second major fatty acid. Palmitic and stearic acids were the major saturates. In pulp/peel oil, the fatty acid profile was characterized by higher amounts of saturates, monoenes, and trienes than in whole berry and seed oils. Neutral lipids comprised >95% of total lipids in whole berry oil and seed oil, while neutral lipids separated in lower level in pulp/peel oil. Triacylglycerols were the predominant neutral lipid subclass and constituted ca. 81.6, 86.6, and 65.1% of total neutral lipids in whole berry, seed, and pulp/peel oils, respectively. Nine triacylglycerol molecular species were detected, wherein three species, C54:3, C52:2, and C54:6, were presented to the extent of approximately 91% or above. The highest level of phytosterols was estimated in pulp/peel oil that contained the highest level of unsaponifiables. In both whole berry and seed oils, campesterol and beta-sitosterol were the sterol markers, whereas Delta5-avenasterol and campesterol were the main 4-desmethylsterols in pulp/peel oil. The tocopherols level was much higher in pulp/peel oil than in whole berry and seed oils. beta- and gamma-tocopherols were the major components in whole berry and seed oils, whereas gamma- and alpha-tocopherols were the main constituents in pulp/peel oil. beta-Carotene and vitamin K(1) were also measured in markedly high levels in pulp/peel oil followed by whole berry oil and seed oil, respectively. Information provided by the present work is of importance for further chemical investigation of goldenberry oil and industrial utilization of the berries as a raw material of oils and functional foods.     

Variation in the seed and oil yields and oil quality in the Indian germplasm of opium poppy Papaver somniferum

The variation in the seed shape, colour and yield, and content, yield and fatty acid composition of seed oil of 109 accessions of opium poppy Papaver somniferum, (majority of them Indian land races), was investigated. The seeds were white, pale yellow or light brown in colour, reniform or round in shape and varied in size up to three fold. The oil content, seed and the oil yield varied between 26 to 52%, 1.0 to 7.4 g/plant and 0.4 to 2.7 g/plant, respectively. The % content of palmitic, oleic and linoleic acid in the seed oil ranged between 9.3 to 40.0%, 7.5 to 58.4% and 0.7 to 72.7%, respectively. On average basis, the levels of major fatty acids in the seed oil were: oleic (37.1%) > palmitic (27.3%) > linoleic acid (17.2%). The palmitoleic, stearic and linolenic acids were present in the oils of only some of the accessions. Two of the accessions yielded linoleic acid rich seed oil of about the same quality as soybean and maize oils, and in four accessions, the proportion of palmitic, oleic and linoleic acids was roughly equal. The palmitic acid was relatively less and linoleic acid more in the seed oil from accessions rich in oil content. The oil that contained higher amount of oleic acid also contained higher amount of palmitic acid and relatively lower amount of linoleic acid. The correlation analyses revealed a strong positive relationship between seed yield and oil yield (r = +0.81), oil yield and oil content (r = +0.54) and oleic acid and palmitic acid content in the seed oil (r = +0.49), and a weak positive relationship between oil content and linoleic acid content of oil (r = +0.24), and a negative correlation was observed between oil content and palmitic acid content (r = –0.32), palmitic acid and linoleic acid (r = –0.55) and oleic acid and linoleic acid contents of oil (r = –0.68). The observations have permitted selection of accessions that are high seed and oil yielding and/or rich in linoleic, palmitic and oleic acids or containing palmitic, oleic and linoleic acids in about equal amounts.     

The influence of bearing cycles on olive oil quality response to irrigation

Five rates of water application were applied in a 4 year study on olive (Olea europaea) varieties 'Barnea' and 'Souri'. Increased irrigation lead to increased tree-scale oil yields, lower polyphenol content, and, frequently, higher oil acidity. These effects were predominant in "off" years. The fatty acid profile was influenced primarily by bearing level and variety and secondarily by irrigation rate. The saturated to unsaturated fatty acid ratio was higher in "off" than in "on" years, and the monounsaturated fatty acid to polyunsaturated fatty acid ratio was higher in "on" years as a result of the fact that oleic and stearic acids were higher in "on" years, while palmitic, palmitoleic, and linoleic acids were greater in "off" years. Squalene was higher in 'Souri' than in 'Barnea' oils, was not affected by bearing cycle, and was consistently lower in oil from trees receiving the lowest irrigation level.     

Dual analysis of triglycerides from certain common lipids and seed extracts

A number of reference oils, two commercial oils, and several oil extracts from seeds of Nicotiana species were analyzed for the fatty acid content and also for triglyceride composition. The seed oils were obtained using an accelerated solvent extraction procedure, which was proven to be very efficient and reproducible. The fatty acids were analyzed after the hydrolysis of the oils, using trimethylsilylation and gas chromatography/mass spectrometry (GC/MS) analysis. The levels of sixteen molecular species of triglycerides in the oils were measured after GC separation using MS for identification and flame ionization detection (FID) for quantitation. The results for the fatty acids and those for triglycerides were combined to generate uniform information regarding the composition of the analyzed oils. For a number of oils, the individual triglyceride quantitation and mass spectra were reported for the first time. The study showed that in some cases, oils with similar fatty acid content do not have the same triglycerides profile. The fatty acids and triglycerides profile for selected Nicotiana species were described for the first time in the literature.     

Molecular species of acylglycerols incorporating radiolabeled fatty acids from castor (Ricinus communis L.) microsomal incubations

Sixty-one molecular species of triacylglycerols (TAG) and diacylglycerols produced from castor microsomal incubations incorporating six different (14)C-labeled fatty acids have been identified and quantified. The preference for incorporation into TAG was in the order ricinoleate > oleate > linoleate > linolenate > stearate > palmitate. Ricinoleate was the major fatty acid incorporated, whereas stearate, linolenate, and palmitate were incorporated at low levels. Twenty-one molecular species of acylglycerols (HPLC peaks) in castor oil have also been assigned. The levels of TAG in castor oil are RRR (triricinolein) > RR-TAG > R-TAG > no R-TAG. The levels of the molecular species within the groups of RR-TAG, RL-TAG, and LL-TAG individually are ricinoleate > linoleate > oleate > linolenate, stearate, and palmitate. The results of the labeled fatty acid incorporation are consistent with ricinoleate being preferentially driven into TAG and oleate being converted to ricinoleate in castor oil biosynthesis.     

Triacylglycerol structure and composition of hydrogenated soybean oil margarine and shortening basestocks

The composition and structures of triacylglycerols (TAG) in a commercially prepared hydrogenated soybean oil margarine basestock [iodine value (IV) 65, 39.7% trans fatty acids] were determined by high-performance liquid chromatography (HPLC) in tandem with atmospheric pressure chemical ionization (APCI) mass spectrometry (MS). The basestock was separated by preparative HPLC into four fractions. Fractions 1 and 4, constituting approximately 8% of the total, were shown to consist of LOO, PLO, and LLS and OSS and PSS, respectively (where L = linoleic, O = oleic, S = stearic, and P = palmitic). APCI will not distinguish between O, oleic cis C18:1, and E, elaidic trans C18:1. Thus, O and E may be used interchangeably in discussion of TAG isomer structures. Fraction 2 consisted of OOO and POO. Fraction 3 consisted of OOO, POO, OOS, and POS. About 80% of the total triglycerides consisted of OOO, POO, and OOS. The trans fatty acid content of the fractions was determined, and the results showed that 92% of the total trans content was found in fractions 2 and 3. A shortening basestock (IV 81.7, 31.8% trans fatty acids) was partially characterized.     

Enrichment of eicosapentaenoic acid from sardine oil with Delta5-olefinic bond specific lipase from Bacillus licheniformis MTCC 6824

Lipase derived from Bacillus licheniformis MTCC 6824 was purified to homogeneity by anion exchange chromatography on Amberlite IRA 410 (Cl-) and gel filtration using Sephadex G-100 as judged by denaturing polyacrylamide gel electrophoresis. The purified lipase was used for hydrolysis of triacylglycerol in sardine oil to enrich Delta5-polyunsaturated fatty acids (Delta5-PUFAs) namely, arachidonic acid (5,8,11,14-eicosatetraenoic acid, ARA, 20:4n-6) and eicosapentaenoic acid (5,8,11,14,17-eicosapentaenoic acid, EPA, 20:5n-3). The individual fatty acids were determined as fatty acid methyl esters (FAMEs) by gas-liquid chromatography and gas chromatography-mass spectroscopy as FAMEs and N-acyl pyrrolidides. The enzyme exhibited hydrolytic resistance toward ester bonds of Delta5-PUFAs as compared to those of other fatty acids and was proved to be effective for increasing the concentration of EPA and ARA from sardine oil. Utilizing this fatty acid specificity, EPA and ARA from sardine oil were enriched by lipase-mediated hydrolysis followed by urea fractionation at 4 degrees C. The purified lipase produced the highest degree of hydrolysis for SFAs and MUFAs (81.5 and 72.3%, respectively, from their initial content in sardine oil) after 9 h. The profile of conversion by lipase catalysis showed a steady increase up to 6 h and thereafter plateaued down. Lipase-catalyzed hydrolysis of sardine oil followed by urea adduction with methanol provided free fatty acids containing 55.4% EPA and 5.8% ARA, respectively, after complexation of saturated and less unsaturated fatty acids. The combination of enzymatic hydrolysis and urea complexation proved to be a promising method to obtain highly concentrated EPA and ARA from sardine oil.     

Changes in triacylglycerol composition during ripening of sea buckthorn (Hippophaë rhamnoides L.) seeds

Changes in the quantitative composition of triacylglycerols (TAGs) in maturing sea buckthorn (Hippopha? rhamnoides L.) seeds were determined by lipase hydrolysis. As a whole, the rate of synthesis of separate TAG classes increased in proportion to both their unsaturation and relative content (weight percent) in total TAGs. Up to the 80th day of maturation, the formation of triunsaturated TAGs was predominant. Subsequently, at the terminal stage of seed ripening, the absolute content (in nanomoles per seed) of a major group of these TAGs containing linolenic and linoleic acyls decreased by approximately 7%, and the increase in the total TAG content was mainly due to the synthesis of TAG molecules including stearic and palmitic acyls in the rac-1,3 positions, as well as those containing oleate in the sn-2 position. At each maturation stage, the composition of the TAGs formed was controlled both by the composition of fatty acids available for TAG synthesis and by the rate of incorporation of a particular fatty acid into the sn-2 position of the TAGs.     

Virgin olive oil normalizes the altered triacylglycerol molecular species composition of adipose tissue in spontaneously hypertensive rats

The present study was conducted in order to evaluate the influence of hypertension on the triacylglycerol (TG) molecular species composition and other lipid classes of rat adipose tissue. In addition, the effect of two dietary oils, with a similar content in oleic acid but different TG moieties, was studied. Virgin olive oil (VOO) or high-oleic sunflower oil (HOSO) was added to a baseline diet (BD) and administrated to Wistar-Kyoto and spontaneously hypertensive rats (SHR) for 12 weeks. Both VOO and HOSO normalized the altered composition of TG molecular species and phospholipid (PL) fatty acids in SHR compared to animals fed BD, although the effect exhibited by VOO was greater. Rats fed HOSO showed a greater palmitic (p < 0.05) and lower linoleic acid (p < 0.05) incorporation into PL but a greater accumulation of linoleic acid-containing TG species, particularly dioleoyl-linoleoyl-glycerol, with a concomitant displacement of trilinolein. Both oils were capable of increasing the lipoprotein lipase (LPL) activity in normotensive rats, but only VOO did so in the SHR. Therefore, it was concluded that although oleic acid-rich diets improve some of the altered parameters of SHR adipose tissue, VOO is more effective than HOSO in this regard.     

Turkish Tombul hazelnut (Corylus avellana L.). 2. Lipid characteristics and oxidative stability

The quality of crude hazelnut oil extracted from Tombul (Round) hazelnut, grown in the Giresun province of Turkey, was determined by measuring lipid classes, fatty acids, and fat soluble bioactives (tocopherols and phytosterols). Oxygen uptake, peroxide value, thiobarbituric acid reactive substances, and alpha-tocopherol levels of stripped and crude hazelnut oils in bulk and oil-in-water (o/w) emulsion systems were also evaluated as indices of lipid oxidation over a 21 day storage period at 60 degrees C in the dark. The total lipid content of Tombul hazelnut was 61.2%, of which 98.8% were nonpolar and 1.2% polar constituents. Triacylglycerols were the major nonpolar lipid class and contributed nearly 100% to the total amount. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol were the most abundant polar lipids, respectively. Sixteen fatty acids were identified, among which oleic acid contributed 82.7% to the total, followed by linoleic, palmitic, and stearic acids. Unsaturated fatty acids accounted for 92.2% of the total fatty acids present. Among oil soluble bioactives, alpha-tocopherol (38.2 mg/100 g) and beta-sitosterol (105.5 mg/100 g) were predominant in hazelnut oil and comprised 88 and 93% of the total tocopherols and phytosterols present, respectively. The results also showed that both stripped and crude hazelnut oils were more stable in terms of lipid oxidation in the bulk oil as compared to those in an o/w emulsion.     

Formation and evolution of monoepoxy fatty acids in thermoxidized olive and sunflower oils and quantitation in used frying oils from restaurants and fried-food outlets

The formation and evolution of monoepoxy fatty acids, arising from oleic and linoleic acids, were investigated in olive oil and conventional sunflower oil, representatives of monounsaturated and polyunsaturated oils, respectively, during thermoxidation at 180 degrees C for 5, 10, and 15 h. Six monoepoxy fatty acids, cis-9,10- and trans-9,10-epoxystearate, arising from oleic acid, and cis-9,10-, trans-9,10-, cis-12,13-, and trans-12,13-epoxyoleate, arising from linoleic acid, were analyzed by gas chromatography after oil derivatization to fatty acid methyl esters. Considerable amounts, ranging from 4.29 to 14.24 mg/g of oil in olive oil and from 5.10 to 9.44 mg/g of oil in sunflower oil, were found after the heating periods assayed. Results showed that the monoepoxides quantitated constituted a major group among the oxidized fatty acid monomers formed at high temperature. For similar levels of degradation, higher contents of the monoepoxides were found in olive oil than in sunflower oil. Ten used frying oils from restaurants and fried-food outlets in Spain were analyzed to determine the contents of the monoepoxides in real frying oil samples. Levels ranged from 3.37 to 14.42 mg/g of oil. Results show that, for similar degradation levels, the monoepoxides were more abundant in the monounsaturated oils than in the polyunsaturated oils.     

Characterization of stearidonic acid soybean oil enriched with palmitic acid produced by solvent-free enzymatic interesterification

Stearidonic acid soybean oil (SDASO) is a plant source of n-3 polyunsaturated fatty acids (n-3 PUFAs). Solvent-free enzymatic interesterification was used to produce structured lipids (SLs) in a 1 L stir-batch reactor with a 1:2 substrate mole ratio of SDASO to tripalmitin, at 65 °C for 18 h. Two SLs were synthesized using immobilized lipases, Novozym 435 and Lipozyme TL IM. Free fatty acids (FFAs) were removed by short-path distillation. SLs were characterized by analyzing FFA and FA (total and positional) contents, iodine and saponification values, melting and crystallization profiles, tocopherols, and oxidative stability. The SLs contained 8.15 and 8.38% total stearidonic acid and 60.84 and 60.63% palmitic acid at the sn-2 position for Novozym 435 SL and Lipozyme TL IM SL, respectively. The SLs were less oxidatively stable than SDASO due to a decrease in tocopherol content after purification of the SLs. The saponification values of the SLs were slightly higher than that of the SDASO. The melting profiles of the SLs were similar, but crystallization profiles differed. The triacylglycerol (TAG) molecular species of the SLs were similar to each other, with tripalmitin being the major TAG. SDASO's major TAG species comprised stearidonic and oleic acids or stearidonic, α-linolenic, and γ-linolenic acids.