Application of palm olein in the production of zero‐trans Iranian vanaspati through enzymatic interesterification

The utilization of palm olein in the production of zero‐trans Iranian vanaspati through enzymatic interesterification was studied. Vanaspati fat was made from ternary blends of palm olein (POL), low‐erucic acid rapeseed oil (RSO) and sunflower oil (SFO) through direct interesterification of the blends or by blending interesterified POL with RSO and SFO. The slip melting point (SMP), the solid fat content (SFC) at 10–40 °C, the carbon number (CN) triacylglycerol (TAG) composition, the induction period (IP) of oxidation at 120 °C (IP₁₂₀) and the IP of crystallization at 20 °C of the final products and non‐interesterified blends were evaluated. Results indicated that all the final products had higher SMP, SFC, IP of crystallization and CN 48 TAG (trisaturated TAG), and lower IP₁₂₀, than their non‐interesterified blends. However, SMP, SFC, IP₁₂₀, IP of crystallization and CN 48 TAG were higher for fats prepared by blending interesterified POL with RSO and SFO. A comparison between the SFC at 20–30 °C of the final products and those of a commercial low‐trans Iranian vanaspati showed that the least saturated fatty acid content necessary to achieve a zero‐trans fat suitable for use as Iranian vanaspati was 37.2% for directly interesterified blends and 28.8% for fats prepared by blending interesterified POL with liquid oils.     

Monitoring of Changes in Composition of Soybean Oil During Deep-Fat Frying with Different Food Types

Changes in the composition of soybean oil during deep‐fat frying with wheat dough (WD) and chicken breast meat (CBM) were comparatively investigated using gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy (FTIR). The amounts of saturated fatty acids (FAs) and short‐chain FAs were increased. The amount of unsaturated FAs was decreased as the processing time increased. An increase in the amount of tetradecanoic acid and 9‐cis‐hexadecanoic acid was observed during the CBM frying only. The FTIR spectrum of frying oil was analyzed by extracting the entire information as the area ratios based on vibration absorptions of the specific functional groups. Changes in content of functional groups, namely cis C=C, trans C=C, C=O, C–O, O–H, and C–H, were studied by the FTIR‐based method. Based on the changes in the content of FAs and functional groups, soybean oil fried with CBM degraded more quickly than that fried with WD. Moreover, good linear correlations between the change in contents of functional groups and the mass percentages of FAs were also observed. The FTIR‐based method could be used in real time to monitor the quality of frying oil during the deep‐fat frying.     

Determination of fatty acids and some undesirable fatty acid isomers in selected Turkish margarines

The fatty acid composition and total trans fatty acid content in 10 margarines produced in Turkey were determined by capillary gas chromatography and Fourier transform‐infrared spectroscopy (FT‐IR) spectroscopy. The fatty acid composition ranged as follows: saturated fatty acids, C16:0 (palmitic) 11.3 to 31.8% and C18:0 (stearic) 5.7 to 8.7%, monounsaturated fatty acids, C18:1 (oleic) 21.8 to 35.7% and C18:1 trans isomers 0.4 to 27.4%, polyunsaturated fatty acid, C18:2 linoleic acid 5.2 to 40.2%. Some positional isomers of C18:1 as cis‐11‐octadecenoic acid varied from 0.7 to 4.6% and cis‐13 trace to 2.4%. The total trans fatty acid contents were between 0.9 and 32.0% when measured with capillary gas chromatography and between 0 and 30.2% with FT‐IR spectroscopy. Some of the margarines analyzed contained trace amount of trans fatty acids which could not be detected by FT‐IR spectroscopy.     

A comparative study of fatty acid profiles in ruminant and non‐ruminant milk

This is a comprehensive study of fatty acid (FA) profiles in milk from bovine, caprine, ovine, asine, and equine species. Milks from these species are universally common as constituents in a variety of different food and dairy products. We have obtained structural information on FAs, and discussed their correlation to health effects. The extracted fat from all species were derivatized to FA methyl esters for analysis by GC‐MS. Large differences in the lipid content and FA composition between ruminants and non‐ruminants were observed. Ovine milk showed the highest lipid content of all the animals tested, both ruminants and non‐ruminants. Among the ruminants, bovine milk was richer in saturated FAs (69.7%) than ovine‐ and caprine milk (57.5 and 59.9%, respectively). Ovine milk contained the highest amounts of monounsaturated FAs (39.1%) and also odd‐ and branched‐chain FAs (5.5%). Milk from the monogastric animals, mares and donkeys, were highest in polyunsaturated FAs with a content of 19.3 and 14.2%, respectively. The assumed health negative trans FAs were analyzed to be highest in the ruminant milk (0.7–1.0%). Milk from these species contained also the highest amount of the health beneficial CLA (0.4–0.7%). Practical applications: This is a comprehensive study of milk from five species analyzed under identical conditions. The different fatty acids and their derivatives are increasingly important components because of the contradictory reports on positive and negative effects on human health. New information on the composition of milk from different species is of great importance. The results may give valuable information to producers and nutritional advisors on the consumption of milk and milk products.     

Effects of frying on the trans‐fatty acid formation in soybean oils

To evaluate the effects of repeated deep‐frying on the trans‐fatty acid (TFA) formation in soybean oils, simultaneous frying experiments were carried out. French fries were prepared using three different types of soybean oil (pressed soybean oil, PSBO; first‐grade solvent extracted soybean oil, FG‐SESBO; and third‐grade solvent extracted soybean oil, TG‐SESBO). French fries were fried intermittently at 180–185°C for a total frying time of 32 h and at an interval time of 30 min. It was found that the initial amount of total TFAs was 0.29 g/100 g, 0.31 g/100 g, and 0.90 g/100 g in PSBO, TG‐SESBO, and FG‐SESBO, respectively. Before the frying started, the C18:1,t‐9, trans‐linoleic acid (TLA), trans‐linolenic acid (TLNA), and total TFA content of the PSBO and TG‐SESBO were significantly lower than in the FG‐SESBO (p<0.05). However, in the frying oil samples, the final concentration of total TFA in the PSBO, TG‐SESBO, and FG‐SESBO were 1.79 ± 0.17 g/100 g, 1.12 ± 0.10 g/100 g, and 1.70 ± 0.07 g/100 g, which was 6.17‐, 3.61‐, and 1.89‐fold higher that in fresh oil, respectively. The highest increasing slopes of C18:1,t‐9, TLA, TLNA, and total TFA were observed in the PSBO. Practical applications : A high intake of TFAs has been shown to lead to an increased risk of coronary heart disease. Plant oils, particularly soybean oil, have been widely used in the food industry in China. Frying is one of the most common methods to cook food. The formation of TFAs during frying has been shown to be closely related to the temperature and duration of the frying process. However, the effects of frying on the formation of TFAs in different soybean oils have not been well studied. In the present study, we demonstrated that increasing the number of frying cycles can cause an intensive increase in the concentration of TFAs in different types of soybean oil, but especially in PSBO.     

Influence of natural antioxidants on the formation of trans‐fatty‐acid isomers during heat treatment of sunflower oil

The intake of foods containing trans fatty acids (TFAs) can have deleterious effects on human health, mainly on the cardiovascular system. Thus, it is important to consider the processes that form TFAs in foods, and the alternatives to minimise their formation. The influence of two added natural antioxidants on TFA formation during heat treatment (120 h at 180°C) of sunflower vegetable oil were examined: rosemary extract (Rosmarinus officinalis L.) (1 g per kg oil) and lutein (0.1 g per kg oil). Changes in FA composition were determined using Ag‐ion SPE and gas–liquid chromatography, with total polar compounds determined using dielectric constant measurements and the index of atherogenicity was calculated. Total TFAs with ≥1 trans double bond increased from 0.91 to 1.71% in control samples; this increase was significantly less with both rosemary extract (1.55%) and lutein (1.43%) additions. Among the individual TFAs, significant increases were seen for C18:1,t‐9, C18:2,t‐9,t‐12 and C18:2,c‐9,t‐12/9‐t,12‐c. Polar compounds also increased, with the highest concentrations in control samples, and significantly less with both rosemary extract and lutein additions. According to results of our study, we can summarize that addition of lutein have greater effect on reduction of TFA formation than rosemary extract. Practical applications: Antioxidants, particularly from plants, are widely used in the food industry. They can provide benefits in food preparation, including improving colour, odour and stability, acting as acid regulators and natural preservatives. They have also become accepted by customers and consumers, and so indirectly they have had effects on consumer perception. Addition of natural antioxidants such as rosemary extract is usually limited by the sensory characteristics of the food, with one study showing that addition of rosemary extract at 1–3 g per kg vegetable oil is recommended. The effects of antioxidants on the formation of TFAs in vegetable oils has not been well studied in the literature. Among the already known benefits, the use of such antioxidants as functional ingredients in lipid technologies might reduce the formation of TFAs during thermal treatment.     

Improved synthesis and characterization of saturated branched‐chain fatty acid isomers

The development of viable technologies for producing green products from renewable fats and oils is highly desirable since such materials can serve as replacements for non‐renewable and poorly biodegradable petroleum‐based products. Mixtures of saturated branched‐chain fatty acid isomers (sbc‐FAs), commonly referred to as isostearic acid, are important intermediates for the production of biodegradable lubricants, cosmetics, emollients, and hydraulic fluids. Present methods for producing sbc‐FAs, however, often give low yields of sbc‐FAs or sbc‐FA preparations with a high content of dimer acid fatty acid co‐products. This study reports an improved route to synthesizing sbc‐FAs from monounsaturated fatty acids using a modified H‐Ferrierite zeolite catalyst in conjunction with small amounts of triphenylphosphine additive. The yields of sbc‐FAs (up to 80 wt%) and co‐products (up to15 wt%) were determined using a modification of a previously reported GC method. A more detailed analysis of the distribution of sbc‐FA isomers in the products was made by the combined use of GC × GC‐TOF‐MS. Additionally, it was found that the H‐Ferrierite zeolite catalyst was recyclable and reusable up to 10 times without significant loss of activity and selectivity for sbc‐FAs.     

Geometrical isomerization of polyunsaturated fatty acids in physically refined rapeseed oil during plant‐scale deodorization

The effect of the operating temperature (between 220 and 270 °C) on the formation of trans isomers of linoleic and linolenic acids in physically refined rapeseed oil during deodorization in a plant‐scale semicontinuous tray‐type deodorizer (capacity 10 t/h) was investigated. The industrial procedures of physical refining consisted of a two‐step bleaching and deodorization process. The degree of isomerization of linoleic acid ranged from 0.33 to 4.77% and that of linolenic acid from 4.43 to 45.22% between 220 and 270 °C, respectively. A relation between the logarithm of the degree of isomerization and the deodorization temperature can be approximated by statistically highly significant linear functions for both linoleic and linolenic acids. Oleic acid was resistant to the heat‐induced geometrical isomerization. The values found for the ratio between the degrees of isomerization of linolenic and linoleic acids, slightly decreasing with increasing temperature, were equal to 13.6 and 12.9 at 230 and 240 °C, respectively. Two trans isomers of linoleic acid, exclusively with one double bond isomerized into trans configuration, and four trans isomers of linolenic acid, mostly with one double bond isomerized into trans configuration, were determined in deodorized rapeseed oils. Linolenic acid was observed to be the main source responsible for the formation of nearly all trans fatty acids in physically refined rapeseed oil. At 235 °C, a deodorization temperature considered as a reasonable technological compromise, the content of trans fatty acids in plant‐scale physically refined rapeseed oil was less than 1% of total fatty acids, which would be acceptable for further application.     

Retraction: Are conjugated linoleic acid (CLA) isomers good or bad trans fats?

Even though trans fatty acids (TFAs) are present in natural sources such as foods from ruminant origins, the development of partially hydrogenated vegetable oil contributed to a significant increase in total TFAs consumption in humans. Currently, TFA consumption is considered to be a risk factor for coronary heart diseases. Researchers are now starting to discover that not all TFAs behave in a similar manner, that is, isomer specificity may be found. Among non‐conjugated TFAs, plant originated TFAs (mainly elaidic and linolelaidic acids) are particularly linked to increased risk for coronary heart diseases, while animal originated TFAs (mainly vaccenic acid) are not. Among conjugated TFAs, two major isomers of conjugated linoleic acid (CLA), cis‐9, trans‐11 and trans‐10, cis‐12, show distinctive biological activities. A number of clinical trials of CLA with effects on body composition have been reported, but effects on coronary heart disease risk factors have been inconsistent. Meanwhile, safety concerns regarding CLA, in particular isomer specificity, have also been raised. Thus, it is critical to identify isomer specific effects of TFAs on particular risk factors, to determine their health impact.     

Lactose fermentation in the presence of C18 fatty acids

Lactose degradation in the presence of C₁₈ long chain fatty acids was examined under anaerobic conditions at 37 °C. The lactose degradation rate was a function of linoleic acid (LA) and oleic acid (OA) concentrations but independent of the amount of stearic acid (SA) added. In cultures fed with LA, lactose was removed within approximately 12 h and within 6 h for cultures inoculated with OA or SA. Glucose, a product of lactose degradation, was only observed in cultures fed with 500–700 mg dm^?3 LA and 1000 mg dm^?3 OA. No galactose was detected under any of the conditions examined. The cause of glucose accumulation is likely due to inhibition of acidogens by LA and OA. Lactate was detected under all conditions examined. LA was more inhibitory on lactate‐consuming organisms than OA and SA and larger amounts of lactate were observed in cultures fed with LA. In addition to lactate, butyrate, propionate and acetate were also observed. Accumulation of volatile fatty acids was a function of the type and concentration of long chain fatty acids. In cultures fed with SA, lower levels of butyrate and acetate were observed when compared with those inoculated with LA and OA and no propionate was detected. Copyright © 2004 Society of Chemical Industry     

Linoleic acid requirement of rats fedtrans fatty acids

The amount of linoleic acid required to prevent undesirable effects of C18trans fatty acids was investigated. In a first experiment, six groups of rats were fed diets with a high content oftrans fatty acids (20% of energy [en%]), and increasing amounts of linoleic acid (0.4 to 7.1 en%). In a second experiment, four groups of rats were fed diets designed to comparetrans fatty acids with saturated andcis-monounsaturated fatty acids of the same chain length at the 2 en% linoleic acid level. After 9–14 weeks, the oxygen uptake, lipid composition and ATP synthesis of heart and liver mitochondria were determined. The phospholipid composition of the mitochondria did not change, but the fatty acid compositions of the two main mitochondrial phospholipids were influenced by the dietary fats.Trans fatty acids were incorporated in all phospholipids investigated. The linoleic acid level in the phospholipids, irrespective of the dietary content of linoleic acid, increased on incorporation oftrans fatty acids. The arachidonic acid level had decreased in most phospholipids in animals fed diets containing 2 en% linoleic acid. At higher linoleic acid intakes, the effect oftrans fatty acids on the phospholipid arachidonic acid level diminished. However, in heart mitochondrial phosphatidylethanolamine,trans fatty acids significantly increased the arachidonic acid level. Despite these changes in composition, neither the amount of dietary linoleic acid nor the addition oftrans fatty acids influenced the mitochondrial function. For rats, a level of 2 en% of linoleic acid is sufficient to prevent undesirable effects of high amounts of dietary C18trans fatty acids on the mitochondrial function.     

Crystallization behavior and polymorphism of poly(1,4‐butylene adipate): Effect of anhydrous orotic acid as nucleating agent

The effect of anhydrous orotic acid (OA), as a biocompatible nucleating agent (NA), on the non‐isothermal and isothermal crystallization behaviors, polymorphic crystalline structure and phase transition of poly(1,4‐butylene adipate) (PBA) was investigated. It is found that the OA increased the crystallization temperature of the PBA in the non‐isothermal crystallization process and decreased the crystallization time of the PBA in the isothermal crystallization process. Meanwhile, the spherulite size decreased and spherulite density increased for the PBA. The OA favored the formation of the PBA α‐form crystal, compared to the neat PBA. In addition, upon incorporation of the OA, the β‐to‐α phase transition rate was enhanced significantly. Mechanisms for the preferential formation of the PBA α‐form crystal and the accelerated phase transition have also been proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42957.     

Identification of n‐6 Monounsaturated Fatty Acids in Acer Seed Oils

Seed oils from Acer species are a potential source of the nutraceutical fatty acids, nervonic acid (cis‐15‐tetracosenoic acid, NA), and γ‐linolenic acid (cis‐6,9,12‐octadecatrienoic acid, GLA). To further characterize the genus, seed fatty acid content and composition were determined for 20 species of Acer. Fatty acid content ranged from 8.2% for Acer macrophyllum to over 36% for A. mono and A. negundo. The presence of very‐long‐chain fatty acids (VLCFA), with chain length of 20‐carbons or greater, and GLA were characteristic features of the seed oils. In all species, erucic acid (cis‐13‐docosenoic acid, EA) was the predominant VLCFA with the highest level of NA being only 8.6% in A. olivianum. Regioselective lipase digestion demonstrated that VLCFA are largely absent from the sn‐2 position of seed triacylglycerol, whereas GLA is primarily located at this position. Five Acer species contained low levels (<2%) of cis‐12‐octadecenoic acid and cis‐14‐eicosenoic acid, uncommon n‐6 fatty acids not previously reported from Acer.     

The impact of fatty acid profile on the physicochemical properties of commercial margarines in Brazil

This study aimed to evaluate how lipid profiles affect the physicochemical properties, fatty acid profiles, and nutritional qualities of Brazilian margarines. We analyzed the texture profiles of 13 margarine samples and characterized their fatty acid composition, solid fat content, crystallization kinetics by NMR and thermal behavior by differential scanning calorimetry. The samples had total fat content ranging from 20% to 82% and low trans fatty acid (TFA) levels, except for two samples (5–7% elaidic acid). The fatty acid compositions of all samples showed a predominance of linoleic (23%–46%), oleic (20%–46%), and palmitic acids (7%–14%), indicating that they were formulated with soybean and palm oils. Saturated fat content ranged from 23% to 31%. Compared to the other evaluated samples, those with higher content of lipid and saturated fatty acids (SFAs) exhibited increased hardness and stickiness but reduced spreadability and adhesiveness. The presence of TFAs resulted in increased plasticity of the samples. Reformulation resulted in products with greater SFA levels, which had a negative impact as it increased the atherogenic index (AI: 0.22–0.48). The HF55 sample contained canola oil-based fat and presented the best nutritional and physical properties. This study is the first to report a complete evaluation of representative margarines, with essential information in reformulating to achieve lower SFA.     

Trans fatty acids in adipose tissue of French women in relation to their dietary sources

This study reports the fatty acid composition of subcutaneous adipose tissue in French women with special emphasis on the content of trans fatty acids originating from two main dietary sources, ruminant fats and partially hydrogenated vegetable oils (PHVO). Adipose tissue trans fatty acid levels from 71 women, recruited between 1997 and 1998, were determined using a combination of capillary gas chromatography and silver nitrate thin-layer chromatography. Results indicate that on average cis monounsaturates accounted for 47.9% of total fatty acids, saturates for 32.2%, and linoleic acid for 14.4%. Cis n−3 polyunsaturates represented only 0.7%. Total content of trans fatty acids was 2.32±0.50%, consisting of trans 18∶1 (1.97±0.49%), trans 18∶2 (0.28±0.08%), and trans 16∶1 (0.06±0.03%). Trans 18∶3 isomers were not detectable. The level of trans fatty acids found in adipose tissue of French women was lower than those reported for Canada, the United States, and Northern European countries but higher than that determined in Spain. Therefore, trans fatty acid consumption in France appears to be intermediate between that of the United States or North Europe and that of Spain. Based on the equation of Enig et al., we estimated the mean daily trans 18∶1 acid intake of French women at 1.9 g per person. The major trans 18∶1 isomer in adipose tissue was Δ11trans, as in ruminant fats. Estimates of relative contribution of trans fatty acid intake were 55% from ruminant fats and 45% from PHVO. This pattern contrasts sharply with those established for Canada and the United States where PHVO is reported to be the major dietary source of trans fatty acids.     

Dietary trans α‐linolenic acid does not inhibit Δ5‐ and Δ6‐desaturation of linoleic acid in man

Dietary trans monoenes have been associated with an increased risk of heart disease in some studies and this has caused much concern. Trans polyenes are also present in the diet, for example, trans α‐linolenic acid is formed during the deodorisation of α‐linolenic acid‐rich oils such as rapeseed oil. One would expect the intake of trans α‐linolenic acid to be on the increase since the consumption of rapeseed oil in the western diet is increasing. There are no data on trans α‐linolenic acid consumption and its effects. We therefore carried out a comprehensive study to examine whether trans isomers of this polyunsaturated fatty acid increased the risk of coronary heart disease. Since inhibition of Δ6‐desaturase had also been linked to heart disease, the effect of trans α‐linolenic acid on the conversion of [U‐¹³C]‐labelled linoleic acid to dihomo‐γ‐linolenic and arachidonic acid was studied in 7 healthy men recruited from the staff and students of the University of Edinburgh. Thirty percent of the habitual fat was replaced using a trans ‘free’‐ or ‘high’ trans α‐linolenic acid fat. After at least 6 weeks on the experimental diets, the men received 3‐oleyl, 1,2‐[U‐¹³C]‐linoleyl glycerol (15 mg twice daily for ten days). The fatty acid composition of plasma phospholipids and the incorporation of ¹³C‐label into n‐6 fatty acids were determined at day 8, 9 and 10 and after a 6‐week washout period by gas chromatography‐combustion‐isotope ratio mass spectrometry. Trans α‐linolenic acid of plasma phospholipids increased from 0.04 ? 0.01 to 0.17 ? 0.02 and cis ? ‐linolenic acid decreased from 0.42 ? 0.07 to 0.29 ? 0.08 g/100 g of fatty acids on the high trans diet. The composition of the other plasma phospholipid fatty acids did not change. The enrichment of phosphatidyl ¹³C‐linoleic acid reached a plateau at day 10 and the average of the last 3 days did not differ between the low and high trans period. Both dihomo‐γ‐linolenic and arachidonic acid in phospholipids were enriched in ¹³C, both in absolute and relative terms (with respect to ¹³C‐linoleic acid). The enrichment was slightly and significantly higher during the high trans period (P<0.05). Our data suggest that a diet rich in trans α‐linolenic acid (0.6% of energy) does not inhibit the conversion of linoleic acid to dihomo‐γ‐linolenic and arachidonic acid in healthy middle‐aged men consuming a diet rich in linoleic acid.     

Effect of Different Frying Methods on the Total <Emphasis Type="Italic">trans</Emphasis> Fatty Acid Content and Oxidative Stability of Oils

The main objective of this study was to determine the effect of different frying oils and frying methods on the formation of trans fatty acids and the oxidative stability of oils. Sunflower, canola and commercial frying oils, the most commonly used oils for frying potatoes in the fast food industry, were used as the frying medium. The value for total polar compounds was highest when commercial frying oil was used in the microwave oven (22.5 ± 1.1). The peroxide value, as an indicator of oil oxidation, was lowest for microwave oven frying (2.53 ± 0.03). The K₂₃₂ and K₂₇₀ values were 0.41 ± 0.04 and 0.18 ± 0.02, respectively, for commercial frying oil in the microwave oven. The lowest free fatty acid content was recorded for the commercial frying oil used in the deep‐fat fryer at 190 °C. The highest iodine value was measured for sunflower oil used in the deep‐fat fryer (148.14 ± 0.07), indicating a greater degree of unsaturation. The lowest trans fatty acid value was recorded for sunflower oil in the microwave oven (0.17 ± 0.05), with a higher overall amount of total trans fatty acids observed for oils after frying in the electrical deep‐fat fryer compared to the microwave. Sunflower oil was favourable for both frying methods in terms of the trans fatty acid content.     

Trans fatty acid isomers in Canadian human milk

The fatty acid composition, totaltrans content (i.e., sum of all the fatty acids which may have one or moretrans double bonds) and geometric and positional isomer distribution of unsaturated fatty acids of 198 human milk samples collected in 1992 from nine provinces of Canada were determined using a combination of capillary gas-liquid chromatography and silver nitrate thin-layer chromatography. The mean totaltrans fatty acid content was 7.19±3.03% of the total milk fatty acids and ranged from 0.10 to 17.15%. Twenty-five of the 198 samples contained more than 10% totaltrans fatty acids, and thirteen samples contained less than 4%. Totaltrans isomers of linoleic acid were 0.89% of the total milk fatty acids with 18∶2Δ9c, 13t being the most prevalent isomer, followed by 18∶2Δ9c, 12t and 18∶2Δ9t, 12c. Using the totaltrans values in human milk determined in the present study, the intake of totaltrans fatty acids from various dietary sources by Canadian lactating women was estimated to be 10.6±3.7 g/person/d, and in some individuals, the intake could be as high as 20.3 g/d. The 18∶1trans isomer distribution differed from that of cow's milk fat but was remarkably similar to that in partially hydrogenated soybean and canola oils, suggesting that partially hydrogenated vegetable oils are the major source of thesetrans fatty acids.     

Influence of native antioxidants on the formation of fatty acid hydroperoxides in model systems

The effect of alpha‐tocopherol (alpha‐T) and quercetin on the formation of hydroperoxides of linoleic and linolenic acids during autoxidation at 60 ± 1 °C was investigated. Three isomers of hydroperoxides were detected using HPLC. Of isomers of linoleic acid hydroperoxides, 13‐hydroperoxy‐octadecadienoic acid trans‐trans (13‐HPODE t‐t), 9‐HPODE cis‐trans (9‐HPODE c‐t) and 9‐HPODE trans‐trans (9‐HPODE t‐t) were identified, constituting 64, 19 and 17% of the total amount, respectively. For linolenic acid, the components 13‐hydroperoxy‐octadecatrienoic acid trans‐trans (13‐HPOTE t‐t), 9‐HPOTE c‐t and 9‐HPOTE t‐t contributed 7, 33 and 60% to the total, respectively. The different dominant hydroperoxide isomers detected in linoleic and linolenic acids during oxidation are related to their chemical structure and the microenvironment of emulsion droplets. The ratios between specific isomers for both fatty acid hydroperoxides did not change during oxidation with or without antioxidants. Alpha‐T effectively inhibited the oxidation of fatty acids and reduced the formation of hydroperoxides. The total amount of the hydroperoxides decreased along with the increase in the concentration of alpha‐T, 1–40 µM. Quercetin inhibited the oxidation of both fatty acids at similar efficiency only at 40 µM concentration. A synergistic antioxidant effect of quercetin with alpha‐T in a binary system on both fatty acids was observed.     

Anti-mutagenic Properties of Mono- and Dienoic Acid Biohydrogenation Products from Beef Fat

Unsaturated fatty acid biohydrogenation products from beef fat and pure fatty acids were subjected to the Ames Salmonella mutagenicity testing, including monounsaturated fatty acids [MUFA: oleic acid, vaccenic acid, elaidic acid; beef fatty acid fractions rich in trans (t)11/t13‐t14‐18:1 (t11,13,14‐Frac), t10‐18:1 (t10‐Frac)] and dienoic fatty acids [linoleic acid, conjugated linoleic isomers cis (c)9,t11‐18:2 and t10,c12‐18:2, and a mixed beef dienoic fatty acid fraction high in c9,t13‐/t8,c12/t11c15‐18:2 (MD)]. Significantly higher anti‐mutagenic effects of oleic acid, vaccenic acid, t11, 13, 14‐Frac, and t10‐Frac against daunomycin were observed at 2.5 mg. All dienoic acids except MD significantly reduced daunomycin mutagenicity at ≥0.25 mg. Anti‐mutagenicity of oleic and vaccenic acids against 2‐aminoanthracene was found at 2.5 and 0.25 mg, respectively. All dienoic acids significantly reduced 2‐aminoanthracene mutagenicity at ≥0.25 mg. Findings of this study show that unsaturated fatty acids, including trans‐fatty acids commonly found in beef, can act as strong anti‐mutagens.