Effect of the unsaturation degree and concentration of fatty acids on the properties of WPI-based edible films

The incorporation of lipids into hydrophilic protein films allows the modification of their barrier properties, improving its commercial application as preservation medium on different foods. The main objective of this study was to develop films from Whey Protein Isolate (WPI) together with saturated and unsaturated fatty acids and to determine the effect of concentration and unsaturation degree on surface tension of the coating solution and on water vapor permeability (WVP), mechanical properties (tensile strength and elongation at break), and opacity, of the films. The results obtained showed that surface tension was significantly decreased by adding unsaturated fatty acids (oleic and linoleic acid), whereas the greatest effect on WVP reduction was achieved with stearic acid. The addition of stearic acid resulted in a decrease of elongation and an increase of tension strength; however unsaturated fatty acid content did not modify the elongation and slightly reduce a tensile strength.     

Utilization of extruded linseed to modify fatty composition of intensively-reared lamb meat: Effect of associated cereals (wheat vs. corn) and linoleic acid content of the diet

Sixty male lambs were used in two trials to study the efficiency of transfer and elongation of linolenic acid (ALA) in muscle and caudal adipose tissue and to assess factors affecting this process and related changes in fatty acid (FA) profile. In experiment 1, lambs were fed a control diet or extruded linseed (L) diet either with wheat (W, rapid starch) or corn (C, slow starch). In experiment 2, lambs were fed L with “normal” rapeseed, or high-oleic rapeseed, or soybean. In experiment 1, L increased ALA proportion and total n-3 PUFA in muscle and adipose tissue. In adipose tissue but not in muscle, LC lambs had higher proportion of ALA than LW lambs. In experiment 2, increasing linoleic acid (LA) intake increased LA proportion in muscle and adipose tissue but did not modify ALA proportion. Moreover, in muscle, it did not change the desaturation and elongation processes of ALA to long-chain n-3 PUFA.     

Automated flow pH-method for the determination of total free fatty acids content in edible oils

An automated flow pH-method for the determination of titratable acidity (TA) in edible oil without titration is proposed, based on pH measurements on an oil sample emulsion in a suitable reagent. The developed flow pH system involves two constant rate flows: the flow of oils samples and the flow of reagent: triethanolamine + KNO₃ + H₂O + i-PrOH, in which oils is insoluble. The flows are mixed in the mixer forming the emulsion in which the free fatty acids (FFA) extraction is started. Then, the emulsion is passed to the coil for completion of FFA extraction and thermostation and then forwarded to pH-cell for pH measurement. Using pH values and linear dependence of pH vs. log (TA) allows the TA determination.The optimum parameters for the automated flow pH-system have been found, i.e., volumes of the mixer and the coils, the rate of sample and reagent, pH and TA ranges. The results of the TA determination in the edible oils were statistically compared with the standard titration method.     

Effect of cooking on protein oxidation in n-3 polyunsaturated fatty acids enriched beef. Implication on nutritional quality

The effect of cooking on protein oxidation was investigated in M. Longissimus thoracis of eight Normand cows fed during a 100 days finishing period with two different diets: a conventional diet (concentrate/straw based diet) and a diet rich in n-3 polyunsaturated fatty acids (PUFAs), obtained by addition to the conventional diet of a mixture of extruded linseed and extruded rapeseed. After 11 days storage, at 4 °C under vacuum, meat was cooked by applying jets of steam. Three experimental heating treatments were tested: two with constant surface temperatures of 65 and 96 °C during 300 s, and one with a continuous increasing surface temperature up to 207 °C. Protein oxidation was evaluated by the measurement of carbonyls, aromatic amino acids, and free thiols content. The formation of Schiff bases due to the reaction of proteins with aldehydic products of the lipid oxidation was also evaluated. Cooking resulted in a significant increase of carbonyl groups and Schiff bases as well as a significant degradation of tyrosine and tryptophan. Nevertheless, enrichment of the animal diet in n-3 PUFAs had minor effects on protein oxidation induced by cooking which are unlikely to be of nutritional significance.     

Lipid damage during frozen storage of Atlantic halibut (Hippoglossus hippoglossus) in active packaging film containing antioxidants

The use of peroxide value (PV), free fatty acids (FFA), thiobarbituric acid reactive substances (TBARS) and p-anisidine value (PA) proved suitable for studying lipid hydrolysis and primary and secondary lipid oxidation in samples of Atlantic halibut throughout frozen storage. After twelve months, the FFA values in the samples packaged with the film containing natural antioxidants (extracted from barley husks) were similar to the FFA value in the control sample after 9 months. Maximum peroxide value in the samples packaged with the antioxidant-containing film was found one month after the maximum value observed in the control sample. After six months, the concentration of malondialdehyde in the control sample was approximately 30–50% higher than in samples packaged in film containing antioxidants. The results confirm the efficacy of natural antioxidants derived from barley husks and antioxidant active packaging film in slowing down lipid hydrolysis and increasing the oxidative stability of Atlantic halibut flesh.     

Trans fatty acids content and fatty acid profiles in the selected food products from Korea between 2005 and 2008

Since a high intake of trans fatty acids (TFA) has been associated with the increased risk of developing cardiovascular disease, food regulation worldwide has been amended with respect to nutrition labeling and health claims on TFA. In the present study, the TFA levels of Korean food products were investigated to assess the regulation effect of TFA labeling. Same Korean food products within 7 different categories were purchased in years 2005 and 2008, and the contents of TFA and lipid and fatty acid composition were investigated. Lipid and TFA contents decreased in all food products manufactured in 2008. TFA levels were 0.01 to 6.88 g/100 g food in 2005, but the levels remarkably decreased to nondetectable level or up to 0.5 g TFA/100 g food in 2008. The foods from 2005 contained a various level of TFA ranging 0.6% to 44.6% of total fatty acids; however, the TFA level significantly decreased in most foods up to 3.8% from year 2008. For TFAs, trans C18:1 levels were greater than trans isomers of C18:2, and the levels in 2005 were significantly reduced in 2008 (P < 0.05). TFA levels at the sn-2 position were up to 48.3% of total fatty acids in 2005, but the level considerably decreased up to 5.4% in 2008. The considerably decreased content of TFA in 2008 suggested that food manufacturers recognized the adverse effect of TFA on human health and followed the compulsory trans fat labeling rule by Korean Food and Drug Administration (KFDA), which started December 2007.     

Identification of the composition of fatty acids in Eucommia ulmoides seed oil by fraction chain length and mass spectrometry

In order to automatically identify fatty acids in plant seed oils, a method was developed to search all saturated fatty acid methyl esters in the sample, subsequently calculate the ECL value of each fatty acid, and finally identify the molecular structure for each component by comparing the ECL of the interest and that in the customised database. Our method was applied to analyse the fatty acid composition of Eucommia ulmoides seed oil. The results show that major polyunsaturated fatty acids are α-linolenic acid (56.5093% of total fatty acids, TFAs) and linolelaidic acid (12.6563% of TFAs). Meanwhile, the main monounsaturated fatty acid is oleic acid whose percentage in the TFAs is 15.8008. Palmitic acid and steartic acid are the dominant saturated fatty acids representing 9.8165% and 2.5942% of TFAs, respectively. The UFA/SFA ratio (6.57) is higher than the recommended value (3) by nutritionists.     

Supercritical carbon dioxide extraction of polyunsaturated fatty acids from Northern shrimp (Pandalus borealis Kreyer) processing by-products

This study investigated the potential of Northern shrimp (Pandelus borealis Kreyer) by-products as a source of omega-3 polyunsaturated fatty acids (ω-3 PUFAs). The by-products (heads, shell and tail) of processing accounted for approximately 50–60% of the catch. Supercritical CO₂ extraction (SFE) of the by-products at 35 MPa and 40 °C generated a deep red oil, rich in ω-3 PUFAs, specifically 7.8 ± 0.06% eicosapentaenoic acid (EPA) and 8.0 ± 0.07 % docosahexaenoic acid (DHA).     

煎炸时间对植物油脂中脂肪酸含量的影响

目的探讨不同煎炸时间对大豆油、花生油和芝麻油3种植物油脂脂肪酸含量变化的影响。方法选取煎炸温度为350℃,煎炸时间分别为0.5、1、3、5、7、25 h,用氢氧化钾-甲醇溶液进行甲酯化,并采用气相色谱-质谱法(gas chromatography-mass spectrometry)对脂肪酸甲酯化溶液进行定量分析。结果随着煎炸时间的延长,油脂中总脂肪酸含量呈现递减趋势。其中,油脂中饱和脂肪酸(SFA)的总含量均呈递增趋势,而不饱和脂肪酸(UFA)的总含量均呈递减趋势。结论煎炸25 h后的大豆油、花生油和芝麻油的饱和脂肪酸(SFA)含量分别由19.03%、14.68%、17.54%增至33.01%、23.24%、27.41%,变化率分别为58.45%、34.43%、56.34%,从饱和脂肪酸的变化率来看,花生油相对更稳定。而其不饱和脂肪酸(UFA)分别由80.84%、85.21%、82.39%减少到59.67%、68.97%、69.41%,变化率分别为19.06%、26.18%、15.75%,从不饱和脂肪酸来看,芝麻油更具稳定性。     

环境因素对纤细角毛藻脂肪酸组成含量的影响

通过对脂肪酸组成成分及含量的分析,探讨光照强度、通气量及生长时间等环境因素对纤细角毛藻脂肪酸的影响。研究结果表明,低光照有利于总不饱和脂肪酸的积累,尤其有利于二十碳五烯酸(EPA)、亚油酸和亚麻酸含量的增加;但是二十碳四烯酸(AA)的含量在高的光照条件下增加;高的通气量有利于纤细角毛藻总脂肪和总不饱和脂肪酸(TUFA)含量的增加,同时有助于AA和EPA含量的增加;在对数生长期收获的纤细角毛藻其细胞内的EPA和AA等总不饱和脂肪酸的产量最高。     

Proximate and fatty acids composition of the muscles and viscera of Asian catfish (Pangasius bocourti)

The objective of this research was to analyse the distribution pattern of proximate composition and fatty acid profiles in different portions of Asian catfish (Pangasius bocourti). The lipid content was found amongst different portions, ranging from 2.95% to 93.32%, being lowest in the caudal–dorsal portion and highest in the viscera. Protein, moisture and ash contents were inversely proportional to the lipid content amongst the body portion. There was no specific tendency for the changes of each fatty acid composition from the different portions. Monounsaturated fatty acid (MUFA) was the most predominant fatty acid found in all tissues, ranging from 32.7% to 39.9%, followed by saturated fatty acids (SFA) ranged from 30.2% to 36.5% of total fatty acid, whereas the total polyunsaturated fatty acids (PUFA) content was the lowest, ranging from 14.8% to 24.0%. This study revealed that the proximate compositions and fatty acids deposition in Asian catfish varied markedly throughout the body portion.     

Effects of γ-irradiation on the α-tocopherol and fatty acids content of raw unpeeled almond kernels (Prunus dulcis)

The present study evaluated fatty acid composition and α-tocopherol content of almond as a function of irradiation dose in order to determine dose levels causing minimal undesirable changes to almonds. Raw unpeeled almonds variety Tuono (Prunus dulcis (Mill.) D. A. Webb) were irradiated using ⁶⁰Co source at dose of 0.5, 1.5, 3, 6, 8 and 10 kGy.     

Synthesis of cyclopropane fatty acids in Lactobacillus helveticus and Lactobacillus sanfranciscensis and their cellular fatty acids changes following short term acid and cold stresses

An implemented GC method to separate and quantify the cell cyclopropane fatty acids lactobacillic (C19cyc11) and dehydrosterculic (C19cyc9) was used to study the adaptive response to sublethal acid and cold stresses in Lactobacillus helveticus and Lactobacillus sanfranciscensis. The comparison of the composition of cellular fatty acids of the two strains and their changes after 2 h of stress exposure under micro-aerobic and anaerobic conditions indicated that the aerobic biosynthetic pathway for unsaturated fatty acids is prevalent in L. sanfranciscensis, while the anaerobic pathway is prevalent in L. helveticus. Indeed in the latter strain, in the presence of a source of oleic acid and under micro-aerobic conditions, C18:1n11 and its post-synthetic derivative C19cyc11 accounted for overall proportion ranging from 52 to 28% of the total FAs. On the other hand L. sanfranciscensis synthesizes by aerobic pathway C18:1n9 and transforms it to C19cyc9. However in this species the cumulative level of these two FAs did not exceed 30%. The relevant proportion of dodecanoic acid in the latter species suggests that carbon chain shortening is the principal strategy of L. sanfranciscensis to modulate fluidity or chemico-physical properties of the membranes.     

植物油脂中反式脂肪酸含量及人体摄入量初估

采用气相色谱法对我国常见植物油脂中的反式脂肪酸含量和分布进行了分析,初步估算了我国居民反式脂肪酸的人均日摄入量。精炼植物油脂中反式脂肪酸含量为：大豆油0．89％～3．48％,菜籽油1．97％～4．76％,玉米油1．75％～6．19％,葵花籽油1．48％～2．36％,花生油0．10％～0．47％,棕榈油0．12％～0．28％,其存在形式以反式多不饱和脂肪酸（t—C18：2、t—C18：3）为主;专用油脂中反式脂肪酸含量为：替可可脂（CBR）和植脂末用油40％～50％,代可可脂（CBS）、烘焙和夹心用油中3％～5％,其存在形式以反式单不饱和脂肪酸（t—C18：1）为主。我国居民反式脂肪酸人均日摄入量为1．06g,其中城市1．44g,农村0．92g,分别占日摄入总能量的0．42％、0．61％和0．36％。     

Sacha inchi (Plukenetia volubilis): A seed source of polyunsaturated fatty acids,tocopherols, phytosterols,phenolic compounds and antioxidant capacity

Fatty acids (FA), phytosterols, tocopherols, phenolic compounds, total carotenoids and hydrophilic and lipophilic ORAC antioxidant capacities were evaluated in 16 cultivars of Sacha inchi (SI) seeds with the aim to valorise them and offer more information on the functional properties of SI seeds. A high α linolenic (α-Ln) fatty acid content was found in all cultivars (ω3, 12.8–16.0 g/100 g seed), followed by linoleic (L) fatty acid (ω6, 12.4–14.1 g/100 g seed). The ratio ω6/ω3 was within the 0.83–1.09 range. γ- and δ-tocopherols were the most important tocopherols, whereas the most representative phytosterols were β-sitosterol and stigmasterol. Contents of total phenolics, total carotenoids and hydrophilic and lipophilic antioxidant capacities ranged from 64.6 to 80 mg of gallic acid equivalent/100 g seed; from 0.07 to 0.09 mg of β-carotene equivalent/100 g of seed; from 4.3 to 7.3 and, from 1.0 to 2.8 μmol of Trolox equivalent/g of seed, respectively, among the evaluated SI cultivars. Results showed significant differences (p < 0.05) among the evaluated SI cultivars in the contents of ω3, ω6, antioxidant capacities and other evaluated phytochemicals. SI seeds should be considered as an important dietary source of health promoting phytochemicals.     

The composition of fatty acids in the tissues of Tunisian swordfish (Xiphias gladius)

The objective of this study was to compare the composition of fatty acids stored in the various parts of swordfish. Muscle and organ sections of a series of swordfish samples were collected. Their chemical analysis allowed the classification of swordfish as a semi-fatty fish, with its byproducts totalling 35.6% of the total fatty acids (TFA) and its white and red muscles (MR) 7.2%. The highest contents were found in the liver (26%), the gonads (4.7%) and the red muscle (RM) (4.5%). The UFA/SFA ratio as recommended by nutritionists is 3; in the liver, skin and RM samples this ratio was, respectively, 3.5, 2.8 and 2.7. There is a high level of unsaturated fatty acids (UFA) in swordfish. More than 40% of the muscular tissues are made up of polyunsaturated fatty acids (PUFA) of the n-3 series (EPA + DHA). The byproducts contain more than 30% of monounsaturated acids characterised by the fatty acids of the n-9 series and particularly by oleic acid.     

油脂加工减控反式脂肪酸技术研究进展

该文简介反式脂肪酸性质、来源、分类、对人体健康主要危害及世界各国管理规定,分析油脂加工过程中反式脂肪酸生成机理、途径及影响其生成工艺技术参数,重点综述阻断或减少油脂加工过程中反式脂肪酸生成途径与方法,并提出减控反式脂肪酸生成技术研究、反式脂肪酸安全风险分析与控制、监督管理措施等方面建议。     

Seasonal variations in total fatty acid composition of muscles and eye sockets of tucunaré (Cichla sp.) from the Brazilian Amazon area

Seasonal variations in total fatty acid compositions of tucunaré, Cichla sp. in the Janauacá Lake of the Amazon basin were determined by GC. Saturated fatty acids (SFAs) were found to be at higher concentrations than monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) in two seasonal periods. Major fatty acids were palmitic (16:0, 48.5–51.6% of total SFA), oleic (18:1ω9, 43.9–50.2% of total MUFA), docosahexaenoic (DHA, 22:6ω3, 13.5–27.9% of total PUFA) and arachidonic acid (AA, 20:4ω6, 16.0–19.6% of total PUFA). Polyunsaturated fatty acids were the most abundant in muscle during the flood period, and more especially fatty acids 22:6ω3 (10%) and 20:4ω6 (7%). There were no significant variations amongst total lipid SFA, MUFA, and PUFA from eye sockets. The ω6 fatty acid percentages were always higher than the ω3 fatty acid percentages in tucunaré, with ω6/ω3 ratios varying between 1.02 and 1.6 in the flood and drought periods.     

Seasonal dynamics of fatty acid content of a common food fish from the Yenisei river,Siberian grayling, Thymallus arcticus

Seasonal variations of fatty acid contents in muscle tissue of one of the main food fish species in Siberian rivers, grayling, Thymallus arcticus, were studied over 3 years. Under a comparatively low range of water temperature variations, spawning appeared to be the main cause of seasonal changes in contents of quantitatively prominent and essential fatty acids in fish filets. In general, fish accumulated essential polyunsaturated fatty acids (PUFA), such as eicosapentaenoic (EPA) and docosahexaenoic (DHA), in their muscle tissue before reproductive seasons and then the PUFA seemed to be transferred into gonads during their formation. Hard roe of Siberian grayling had 3–4 times higher PUFA contents, than had that of the muscle tissue. The fish species, T. arcticus, was found to be a valuable source of the essential PUFA, including EPA and DHA, for human diet.