100 resultados para Linoleic acid


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Studies have been carried out in order to increase the stability of vegetable oils due to economic and health protection reasons. There is a growing interest in the addition of natural antioxidants; especially herbs and spices. For this reason, this study aimed at evaluating the antioxidant potential of the oleoresins of oregano, basil, and thyme, as well as their behavior when applied to soybean oil under various concentrations. Firstly, the antioxidant activity was determined by the β-carotene/linoleic acid system and by the quantification of total phenolic compounds. Next, different concentrations of oleoresins (500 to 3000 mg.kg-1) were added to the soybean oil, and its antioxidant potential was analyzed using the oxidative stability through a Rancimat equipment. The value of 3000 mg.kg-1 of thyme and oregano oleoresins was the concentration that presented the greatest oxidative stability to soybean oil making them a natural alternative to vegetable oil conservation.

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The objective of this work was to evaluate the influence of diets containing different lipid sources on eggs quality during refrigerated storage, on yolk fatty acid composition, and on cholesterol in the yolk. Four diets were used containing Soy Oil (SO), Sunflower Seed (SS), and Meat and Bone Meal + Soy Oil (MBM + SO) or Meat and Bone Meal + Tallow (MBM + TA). The experiment followed a factorial design 4 × 3 with four dietary treatments and three storage times. The eggs were stored at 4 °C for 0, 30, and 60 days. The collected eggs were analyzed for egg weight loss, Haugh units, yolk moisture, yolk lipid oxidation, and cooked yolk firmness. Refrigerated storage reduced Haugh units, and increased yolk moisture. Sixty days of storage time reduced the firmness of hard-cooked yolk. There was an interaction between dietary treatment and storage time for egg weight loss and lipid oxidation. With regard to yolk fatty acid profile, MBM + TA diet increased the contents of palmitic and palmitoleic acids. The levels of oleic and arachidonic acids were higher in yolks from birds fed with SS diet. Linoleic acid level was higher in the yolk from treatment with SO diet. Diets containing MBM + SO induced higher levels of docosahexaenoic acid. Yolk cholesterol content was reduced with the inclusion of SS in the diet. Therefore, the type of lipid present in the diet and refrigerated storage for 60 days at 4 °C can affect the egg quality.

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Butter samples were evaluated for free fatty acids, peroxide value, cholesterol, and fatty acid composition focusing on the trans isomer and conjugated linoleic acid (CLA). Sixty six samples were analyzed. Thirty six were collected in Brazil, eighteen in France, and twelve in Argentina. Samples were evaluated by free fatty acids, peroxide value, total lipid, cholesterol and fatty acid composition. The free fatty acid content varied from 0.16 to 0.46 g.100 g-1 and the peroxides value levels from 0.35 to 1.80 meq.kg-1. The cholesterol content varied from 192.8 to 226.3 g.100 g-1 and the total lipid content varied from 81.8 to 86.8 g.100 g-1. The levels of saturated, monounsaturated, and polyunsaturated fatty acids varied from 43.86 to 52.74, from 21.65 to 23.34, and from 2.11 to 2.89 g.100 g-1, respectively. The conjugated linoleic acid (CLA) content varied from 0.56 to 0.86 g.100 g-1 and the levels of total trans isomer varied from 2.18 to 3.81 g.100 g-1.

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Yellow mombin is a fruit tree that grows spontaneously in the Semi-Arid Northeastern Brazil. Its fruits are still extractively exploited. The pulp of yellow mombin fruit stands out regarding the commercial aspect due to the characteristic flavor and aroma felt when consumed in diverse ways. This study aimed to evaluate the presence of bioactive compounds, total extractable polyphenols, and antioxidant activity of yellow mombin fruits (Spondias mombin, L.), from clone and ungrafted genotypes. The fruits were harvested at commercial maturity from twelve yellow mombin tree genotypes from an experimental orchard located at the municipality of Joao Pessoa, Paraíba, Brazil, and evaluated for chlorophyll, carotenoids, yellow flavonoids, total extractable polyphenols, and antioxidant activity, which was measured by the β-carotene/linoleic acid method. The antioxidant activity showed a percentage of inhibition of oxidation higher than 75% for all genotypes evaluated at the time of 120 minutes. The fruits from clone genotypes showed a higher percentage of antioxidant activity.

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The objective of this study was to assess the effect of the addition of cashew nuts meal (0, 5, 10, 15, 20, and 25%) to laying hen diets on egg quality and yolk composition. The variables studied were: egg weight, specific gravity, Haugh Units, percentages of shell, albumen, and yolk, moisture, total solids, total lipids, fatty acids profile, and yolk cholesterol. The addition of up to 25% of cashew nuts meal to hen diets did not affect egg quality and freshness, moisture and total solids content. However, an increase in total lipid content and a decrease in yolk pigmentation was observed. Oleic acid level increased in the yolk, whereas palmitic, stearic, and linoleic acid levels decreased. The addition of cashew nuts meal increased the monounsaturated/saturated fatty acid ratio in the yolk and reduced the cholesterol content. Therefore, the use of cashew nuts meal in laying hen diets favorably modifies the fatty acid composition of egg yolk and contributes to a better acceptance of this food by consumers since it also reduces yolk cholesterol levels.

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This study evaluated the nutritional value of sesame and flaxseed oils and their effects on the lipid and glucose profile of rats fed diets containing different fat combinations. Fatty acid composition, refractive index, and iodine and saponification values were analyzed to characterize the oils. In the biological assay, Wistar rats were fed different diets, whose fat composition consisted of varying combinations of flaxseed oil, sesame oil, and animal fat. The primary constituents of the sesame oil were oleic (28.6%), linoleic (28.4%), and lauric acid (14.6%); for the flaxseed oil they were alpha-linolenic (39.90%), oleic (17.97%) and linoleic acid (12.25%). The iodine and saponification values of the oils were within the reference range. Rats fed flaxseed oil-based diets had the lowest serum cholesterol values, whereas rats fed diets with flaxseed oil + sesame oil + animal fat had the highest glucose levels. HDL levels decreased significantly with flaxseed oil. Sesame and flaxseed oils are sources of polyunsaturated fatty acids (PUFA), and the flaxseed oil-based diet had a hypocholesterolemic effect, whereas sesame oil showed oxidative stability since it contains high levels of monounsaturated and saturated fatty acids.

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The increased marketing of olive oil in Brazil has intensified legal requirements to ensure regulation of this product. The measurement of the specific extinction at 270 nm (E 270) and content of stigmastadiene can be used to assess the presence of refined oils in virgin olive oil. During the vegetable oil refining process, compounds with conjugated double bonds are generated from unsaturated fatty acids that absorb at 270 nm and sterols, such as stigmasta-3,5-diene. To compare these parameters, seven samples of extra virgin olive oil and three samples of olive oil (blend of virgin and refined) were analyzed. Among the samples analyzed, four extra virgin samples had levels of stigmastadiene and E 270 higher than expected, among which two were adulterated with seed oil (rich in linoleic acid) and the other two with olive pomace oil. The results demonstrate the higher sensitivity of stigmastadiene to determine the presence of the refined oil in virgin olive oil and good agreement with determining E 270. The latter technique is a simple, quick, and low cost method of determination that can be easily implemented in laboratories to assist in the screening and regulation of olive oils sold in Brazil.

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The acceptance of tung oil enriched diet and the incorporation of conjugated linolenic acid - CLnA into fillets of Genetically Improved Farmed Tilapia (GIFT) were investigated. The diet was well accepted, and after 10 days CLnA was incorporated into the fillets with a 1.02% content of total fatty acids (FA). In addition, biosynthesis of the conjugated linoleic acid isomers - CLA (0.31% of fillet total FA content) from CLnA, and the presence of alpha-linolenic acid - LNA (1.08% of fillet total FA content), eicosapentaenoic acid - EPA (2.85% of fillet total FA content) and docosahexaenoic acid - DHA (3.08% of fillet total FA content) were observed. Therefore, the consumption of this fish can increase the intake of different FA (CLnA, CLA, LNA, EPA and DHA), which play an important role in human metabolism.

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Grape seed oil (GSO) is not often consumed in Brazil and little is known of its nutritional value. Around the world there are already studies that point to the high levels of minority bioactive compounds and their relation to health benefits. The main constituent of GSO is linoleic fatty acid, some works are controversial and there is no consensus in literature regarding their effect on the animal organism. Thus, this study aimed to present a review of GSO and show the potential health effects of its major components, not only linoleic acid, but also γ-tocotrienol and β-sitosterol, and finally, their influence on lipid-modulating, anti and pro oxidative parameters.

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Chemical composition and nutritive value of hot pepper seeds (Capsicum annuum) grown in Northeast Region of China were investigated. The proximate analysis showed that moisture, ash, crude fat, crude protein and total dietary fiber contents were 4.48, 4.94, 23.65, 21.29 and 38.76 g/100 g, respectively. The main amino acids were glutamic acid and aspartic acid (above 2 g/100 g), followed by histidine, phenylalanine, lysine, arginine, cysteine, leucine, tryptophan, serine, glycine, methionine, threonine and tyrosine (0.8-2 g/100 g). The contents of proline, alanine, valine and isoleucine were less than 0.8 g/100 g. The fatty acid profile showed that linoleic acid, palmitic acid, oleic acid, stearic acid and linolenic acid (above 0.55 g/100 g) as the most abundant fatty acids followed lauric acid, arachidic acid, gondoic acid and behenic acid (0.03-0.15 g/100 g). Analyses of mineral content indicated that the most abundant mineral was potassium, followed by magnesium, calcium, iron, zinc, sodium and manganese. The nutritional composition of hot pepper seeds suggested that they could be regarded as good sources of food ingredients and as new sources of edible oils.

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Abstract This study aimed to characterize pomegranate seed oil and evaluate its quality and stability parameters against those of linseed oil. The profile of fatty acids and phytosterols and the content of tocopherols were analyzed by gas chromatography and high performance liquid chromatography, respectively. The quality of both oils was assessed as recommended by the American Oil Chemists' Society (AOCS) and stability was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene bleaching (coupled oxidation of β-carotene/linoleic acid) and Rancimat® assays. While α-linolenic acid (52%) was the most abundant fatty acid in linseed oil (LO), punicic acid (55%) was highest in pomegranate seed oil (PSO). Tocopherols and phytosterols (175 and 539 mg/100 g, respectively) were greater in PSO than in LO (51 and 328 mg/100 g, respectively). Both oils met quality standards. The β-carotene bleaching and the DPPH assays showed greater oxidative stability for PSO than for LO. The Rancimat® method, on the other hand, indicated low stability for both oils.

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Fatty acid and sterol analysis were performed on Phytomonas serpens and Phytomonas sp. grown in chemically defined and complex medium, and P. françai cultivated in complex medium. The three species of the genus Phytomonas had qualitatively identical fatty acid patterns. Oleic, linoleic, and linolenic were the major unsaturated fatty acids. Miristic and stearic were the major saturated fatty acids. Ergosterol was the only sterol isolated from Phytmonas sp. and P. serpens grown in a sterol-free medium, indicating that it was synthesized de novo. When P. françai that does not grow in defined medium was cultivated in a complex medium, cholesterol was the only sterol detected. The fatty acids and sterol isolated from Phytomonas sp. and P. serpens grown in a chemically defined lipid-free medium indicated that they were able to biosynthesize fatty acids and ergosterol from acetate or from acetate precursors such as glucose or threonine.

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The seeds of 14 species from the ‘caatinga’, a dry forest ecosystem of the semiarid region of northeast Brazil, were analysed for total protein and total lipid contents, as well as fatty acid distribution. The seeds of Argemone mexicana L., an introduced and naturalized species in Brazil, commonly found in ‘caatingas’ and other vegetation, were also analysed. The protein contents ranged from 123 g.kg-1 to 551 g.kg-1, higher contents being found in species of Leguminosae, but also in Jatropha mollissima (Pohl) Baill. (Euphorbiaceae, 409 g.kg-1). Oil contents ranged from 10 g.kg-1 to 400 g.kg-1. The contents of protein and oil were found to be inversely proportional in the seeds of most species, the figures for proteins being generally higher than those of oils. Most species presented either oleic or linoleic as predominant fatty acids. Cardiospermum cf. corindum L. presented eicosenoic acid as the predominant fatty acid.

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The effect of free cholesterol on the fatty acid composition and growth of rat fetal enterocytes was investigated in the absence and presence of 10% (v/v) fetal calf serum. Cholesterol caused a significant reduction of cell number after 6 and 12 h in culture. The fatty acid composition of enterocytes cultured in the presence of serum was also changed by the presence of 20 µM cholesterol. The fatty acid profile was determined by HPLC using fluorescence detection (325 nm excitation and 395 nm emission). Cholesterol (20 µM) increased the proportion (given in percentage of the total fatty acids) of the following fatty acids in cultured cells: lauric (by 42%), oleic (by 34%), linoleic (by 44%) and gamma-linolenic (by 20%) acids and reduced the proportion of palmitic (by 12%), stearic (by 20%), arachidonic (by 21%) and docosahexaenoic (by 44%) acids. In addition to modifying the content of individual fatty acids, cholesterol increased the polyunsaturated/saturated fatty acid ratio from 0.48 to 0.67 and the unsaturation index from 67.12 to 75.30. This is the first evidence that cholesterol modifies fatty acid composition possibly via de novo fatty acid synthesis and desaturation.

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The aim of the present study was to investigate the effects of daily intragastric administration of bullfrog oil (oleic, linoleic and palmitoleic acid-rich oil), corresponding to 0.4% of body weight for four weeks, on fatty acid composition and oxidative stress (lipid peroxidation and catalase activity) in mouse liver. The activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT), biomarkers of tissue injury, were determined in liver homogenates and serum. The proportions of 18:2n-6, 20:4n-6, 20:5n-3, and 22:6n-3 (polyunsaturated fatty acids, from 37 to 60%) in the total fatty acid content were increased in the liver of the bullfrog oil-treated group (P < 0.05) compared to control. At the same time, a significant decrease in the relative abundance of 14:0, 16:0, and 18:0 (saturated fatty acids, from 49 to 25%) was observed. The hepatic content of thiobarbituric acid reactive substances (TBARS) was increased from 2.3 ± 0.2 to 12.3 ± 0.3 nmol TBA-MDA/mg protein and catalase activity was increased from 840 ± 32 to 1110 ± 45 µmol reduced H2O2 min-1 mg protein-1 in the treated group. Bullfrog oil administration increased AST and ALP activities in the liver (from 234.10 ± 0.12 to 342.84 ± 0.13 and 9.38 ± 0.60 to 20.06 ± 0.27 U/g, respectively) and in serum (from 95.41 ± 6.13 to 120.32 ± 3.15 and 234.75 ± 11.5 to 254.41 ± 2.73 U/l, respectively), suggesting that this treatment induced tissue damage. ALT activity was increased from 287.28 ± 0.29 to 315.98 ± 0.34 U/g in the liver but remained unchanged in serum, whereas the GGT activity was not affected by bullfrog oil treatment. Therefore, despite the interesting modulation of fatty acids by bullfrog oil, a possible therapeutic use requires care since some adverse effects were observed in liver.