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1.
Maylet Hernández-Martínez Tzayhri Gallardo-Velázquez Guillermo Osorio-Revilla 《Journal of the American Oil Chemists' Society》2011,88(10):1485-1495
In this study, the fatty acid profile of 42 margarines marketed in Mexico was identified and quantified including the total
trans fatty acids (TFA). The ratio of the sum of cholesterol-lowering fatty acids CLFA (cis-oleic, linoleic and α-linolenic fatty acids) to the sum of cholesterol-raising fatty acids CRFA (C12:0, C14:0, C16:0, TFA)
and the ω6/ω3 ratio were calculated to evaluate the nutritional quality of the margarine samples. The results showed that
the high content of C12:0, C14:0 and C16:0 fatty acids in some samples indicated the use of coconut and palm oils instead
of partially hydrogenated fatty acids in order to decreased TFA content. Of the samples, 33% had less than 1 g/100 g of fat
which could be considered as “free from TFA” according to the Danish Legislation. The ω6/ω3 ratio ranged between 5.85:1 and
25.85:1, the ideal relation being 5–10:1. The CLFA/CRFA ranged from 0.46 to 3.10, being the recommended ratio as high as possible.
Of the 42 margarines, only five samples had an acceptable fatty acid profile, that is, low TFA and saturated fatty acids,
high monounsaturated fatty acids content and adequate ω6/ω3 and CLFA/CRFA ratios. 相似文献
2.
Bakery shortenings prepared by hydrogenation contain high levels of trans fatty acids, which are considered to be risk factors for cardiovascular disease. The shortenings prepared from maogo kernel
and mahua fats have no trans fatty acids. Mahua fat was fractionated by dry fractionation to obtain a high-melting fraction (10% yield, Mh1). Mango fat
was fractionated by two-stage solvent fractionation, separating about 15% high-melting fraction (Mk1) in the first stage,
followed by 40% stearin (Mk2) in the second stage. The formulation containing 80% Mh1 and 20% of mango middle stearin fraction
(Mk2) showed melting characteristics and onset and enthalpy of crystallization similar to those of commercial hydrogenated
shortenings designed for cakes and biscuits. The formulation suitable for puff pastry shortening was prepared by blending
50% mango 1st stearin (Mk1) and 50% mahua fat with addition of 5–7% of fully hydrogenated vegetable oil. The formulations
having melting characteristics similar to those of commercial cake and biscuit shortenings were also prepared by blending
40% mango fat and 60% mahua fat with 5–7% incorporation of fully hydrogenated peanut oil. However, these formulations showed
delayed transition to the stable forms compared to those of commercial samples. Fatty acid composition revealed that commercial
hydrogenated shortenings consisted of 18–29% trans oleic acid, whereas the formulations we prepared did not contain any trans acids. The iodine values of commercial samples were 57–58, whereas the value for the formulations prepared were 47–53. The
consistency of the prepared samples as measured by cone penetrometer was slightly harder than commercial samples. These studies
showed that it is possible to prepare bakery shortenings with no trans fatty acids by using mango and mahua fats and their fractions. 相似文献
3.
Eduardo A. Rodríguez-Leyes Víctor L. González Canavaciolo David Marrero Delange Abel R. Sgambelluri Enríquez Yuliamny Adames Fajardo 《Journal of the American Oil Chemists' Society》2007,84(8):765-767
The present study targeted the whole-fruit oil yield and fatty acid composition from five of the most abundant Arecaceae species grown in Cuba. The oil yields (% dry weight), determined by the Soxhlet extraction technique with hexane, were 25.5,
5.3, 6.9, 5.4, and 6.4% for Roystonea regia, Colpothrinax wrightii, Sabal maritima, Sabal palmetto and Thrinax radiata, respectively. The free fatty acid (FFA) content varied from 2.7 to 6.8%. Fatty acid (FA) profiles of the oils indicated
that lauric acid (13.7–44.4%), myristic acid (9.4–22.4%) and palmitic acid (9.2–17.1%) as major saturated FA; whereas oleic
acid (9.6–42.7%) and linoleic acid (9.3–17.0%) as major unsaturated FA. R. regia fruit seemed the most promising among Arecaceae grown in Cuba because of its high oil yield and low oil FFA content. 相似文献
4.
Tamer Özcan 《Journal of the American Oil Chemists' Society》2007,84(7):653-662
Total oil content and the composition of fatty acids were analyzed in the acorns of 16 Quercus taxa from Turkey. The range of total fat varied between 0.7 and 7.4%. Oleic (10.2–54.4%), linoleic (24.2–49.1%), palmitic
(13.4–30.4%), alpha linolenic (1.5–8.6%) and stearic acid (1.5–4.5%) were major fatty acids for all taxa. Significantly differences
at section level were found (p < 0.05) for palmitic, stearic and oleic acid concentration. Saturated (17.0–38.6%), mono unsaturated (11.0–55.5%) and unsaturated
fatty acids (57.4–81.6%) in total oil were also significantly different between section Quercus, Cerris and Ilex (p < 0.05). In addition, sectional differences were significant (p < 0.02) for the relative concentrations of saturated fatty acids compared to mono, poly and total unsaturated fatty acids.
Considerable variation of individual fatty acid levels were observed in related species and varieties. The species from section
Ilex Loudon exhibited the highest levels of saturated fatty acid while the lowest levels were found in Q. brantii, Q. libani and Q. trojana from section Cerris Loudon. These species also had the highest levels of unsaturated fatty acids. Whereas the lowest values were detected in
the species of section Ilex. Both varieties of Q. cerris showed significant differences (p < 0.05) from the other species in section Cerris for all parameters, except for stearic acid and exhibited little variations among their individual populations. Different
concentrations of fatty acids may be useful biochemical markers for the characterization of Quercus at the infrageneric level. Interesting ratios of linoleic:α-linolenic acid especially in Q. robur ssp. robur, Q. hartwissiana, Q. vulcanica, Q. ithaburensis ssp. macrolepis and Q. libani also were detected with respect to dietary reference for fatty acid intake. 相似文献
5.
G. R. List K. Warner P. Pintauro M. Gil 《Journal of the American Oil Chemists' Society》2007,84(5):497-501
Partially hydrogenated soybean oils (90–110 IV) were prepared by electrochemical hydrogenation at a palladium/cobalt or palladium/iron
cathode, moderate temperature (70–90 °C) and atmospheric pressure. The trans fatty acid (TFA) contents of 90–110 IV products ranged from 6.4 to13.8% and the amounts of stearic acid ranged from 8.8 to
15.4% (the higher stearic acid contents indicated that some reaction selectivity had been lost). The solid fat values and
melting point data indicated that electrochemical hydrogenation provides a route to low-trans spreads and baking shortenings. Shortenings produced by conventional hydrogenation contain 12–25% trans fatty acids and up to 37% saturates, whereas shortening fats produced electrochemically had reduced TFA and saturate content.
Electrochemical hydrogenation is also a promising route to low-trans spread and liquid margarine oils. Compared to commercial margarine/spread oils containing 8–12% TFA, the use of electrochemical
hydrogenation results in about 4% TFA.
Names are necessary to report factually an available data: the USDA neither guarantees nor warrants the standard of the product,
and the use of the name USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献
6.
Physical and chemical properties of trans-free fats produced by chemical interesterification of vegetable oil blends 总被引:1,自引:0,他引:1
V. Petrauskaite W. De Greyt M. Kellens A. Huyghebaert 《Journal of the American Oil Chemists' Society》1998,75(4):489-493
Fat blends, formulated by mixing a highly saturated fat (palm stearin or fully hydrogenated soybean oil) with a native vegetable
oil (soybean oil) in different ratios from 10:90 to 75:25 (wt%), were subjected to chemical interesterification reactions
on laboratory scale (0.2% sodium methoxide catalyst, time=90 min, temperature=90°C). Starting and interesterified blends were
investigated for triglyceride composition, solid fat content, free fatty acid content, and trans fatty acid (TFA) levels. Obtained values were compared to those of low- and high-trans commercial food fats. The interesterified blends with 30–50% of hard stock had plasticity curves in the range of commercial
shortenings and stick-type margarines, while interesterified blends with 20% hard stock were suitable for use in soft tubtype
margarines. Confectionery fat basestocks could be prepared from interesterified fat blends with 40% palm stearin or 25% fully
hydrogenated soybean oil. TFA levels of interesterified blends were low (0.1%) compared to 1.3–12.1% in commercial food fats.
Presented at the 88th AOCS Annual Meeting and Expo, May 11–14, 1997, Seattle, Washington. 相似文献
7.
A Fourier transform infrared spectroscopic procedure was used to analyze 34 edible fats (22 shortenings and 12 vegetable margarines)
as neat fats (IRNF) to determine their total trans fatty acid (TFA) content. The sloping baseline was corrected with a reference spectrum based on a nonprocessed olive oil.
The calibration was done using seven partially hydrogenated fats with an individual TFA content previously determined by the
combination of gas chromatography (GC) with argentation thin-layer chromatography. Taking into account the different absorptivities
of various trans isomers, different correction factors were calculated using the calibration standards (0.83 and 1.71 for single trans bonds in both diethylene and triethylene and for trans, trans-diethylene fatty acids, respectively) and applied to calculate the total TFA of samples. Moreover, the samples were converted
to their methyl esters and reanalyzed following the same procedure (IRFAME). Differences in TFA content of fats were not found when a t-test was used to compare the results obtained by IRNF vs. either IRFAME or GC, suggesting that IR of neat fats could be used, thus avoiding the need to prepare sample solutions in organic solvents
and to prepare fatty acid methyl esters. The mean TFA content (determined by IRNF) of a representative group of Spanish shortenings (22 samples) that varied widely in terms of fat sources, processes, and
purposes (bakery, sandwiches, ice cream, coatings, chocolate coverings) was 6.55±11.40%, although more than 54% contained
<3% of TFA. Fatty acid composition of shortenings by direct GC using a 100-m polar cyanopolysiloxane capillary column indicated
that the mean trans-18∶2 isomer content was 0.58%, ranging from 0.9 to 3.4%. Small amounts of trans-18∶3 isomers (<0.3%) were observed in 18 of the 22 shortenings studied; the maximal value was <2%. The mean value of the
fraction saturated+TFA of shortenings was high (59.95±12.73%), including two values higher than 83%. 相似文献
8.
The effect of dietary conjugated linoleic acid (CLA) supplementation in combination with fat from vegetable versus animal
origin on the fatty acid deposition, including that of individual 18:1 and 18:2 (conjugated and non-conjugated) isomers, in
the liver and muscle of obese rats was investigated. For this purpose, 32 male Zucker rats were randomly assigned to one of
four diets containing palm oil or ovine fat, supplemented or not with 1% of 1:1 cis(c)9,trans(t)11 and t10,c12 CLA isomers mixture. Total fatty acid content decreased in the liver and muscle of CLA-fed rats. In the liver, CLA increased
saturated fatty acids (SFA) in 11.9% and decreased monounsaturated fatty acids (MUFA) in 6.5%. n-3 Polyunsaturated fatty acids
(PUFA) relative proportions were increased in 30.6% by CLA when supplemented to the ovine fat diet. In the muscle, CLA did
not affect SFA but decreased MUFA and PUFA percentages. The estimation of Δ9-indices 16 and 18 suggested that CLA inhibited
the stearoyl-CoA desaturase activity in the liver (a decrease of 13–38%), in particular when supplemented to the ovine fat
diet. Concerning CLA supplementation, the t10,c12 isomer percentage was 60–80% higher in the muscle than in the liver. It is of relevance that rats fed ovine fat, containing
bio-formed CLA, had more c9,t11 CLA isomer deposited in both tissues than rats fed palm oil plus synthetic CLA. These results highlight the importance
to further clarify the biological effects of consuming foods naturally enriched in CLA, alternatively to CLA dietary supplementation. 相似文献
9.
Jing Li Yawei Fan Zhiwu Zhang Hai Yu Yin An John K. G. Kramer Zeyuan Deng 《Lipids》2009,44(3):257-271
Human milk was obtained from 97 healthy lactating women from five different regions in China. Twenty-four hour dietary questionnaire
identified the foods consumed that showed distinct differences in food types between cities. The southern and central regions
had higher levels of total trans fatty acids (TFA) and conjugated linoleic acids (CLA) in human milk than the northern region. The major isomers in human
milk from the northern region were vaccenic and rumenic acids, whereas the other regions had a random distribution of these
isomers. This was consistent with the isomer distribution in the refined vegetable oils used and their increased formation
during high temperature stir-frying. The human milk composition showed little evidence that partially hydrogenated fats were
consumed, except eight mothers in Guangzhou who reported eating crackers, plus four other mothers. The TFA concentration in
these human milk samples was higher (2.06–3.96%). The amount of n-6 (1.70–2.24%) and n-3 (0.60–1.47%) highly unsaturated fatty
acids (HUFA) in human milk and the resultant ratio (1.43–2.95) showed all mothers in China had an adequate supply of HUFA
in their diet. Rapeseed oil was consumed evidenced by erucic acids in human milk. The levels of erucic acid were below internationally
accepted limits for human consumption. The levels of undesirable TFA and CLA isomers in human milk are a concern. Efforts
to decrease the practice of high temperature stir-frying using unsaturated oils, and a promotion to increase consumption of
dairy and ruminant products should be considered in China. 相似文献
10.
Robert Hrastar Ling-Zhi Cheong Xuebing Xu Rasmus Leth Miller Iztok Jože Košir 《Journal of the American Oil Chemists' Society》2011,88(4):581-588
Camelina sativa oil is characterized by its high content (up to 40 wt%) of α-linolenic acid and its unique flavor. It is considered to have
beneficial health properties and is suitable for food and cosmetic uses. In the present study, response surface methodology
was used to optimize processing parameters for bench-scale deodorization of camelina oil. The mathematical models generated
described the effects of process parameters (temperature, steam flow, time) on several deodorization quality indicators: free
fatty acids (FFA), trans fatty acids (TFA), color, and polymerized triglycerides (PTG). These newly established models can be used as a tool to identify
optimum deodorization process conditions within chosen constraints. Based on the optimization of minimum retained FFA with
the constraint of a maximum allowable TFA, deodorization parameters can be defined. At a constant steam flow rate of 42 ml/h,
a temperature range of 210–220 °C, and deodorization time of 70–120 min were defined. 220 °C appears to be a critical upper
temperature limit; above this temperature, isomerization rates significantly increase. 相似文献
11.
S. Gómez-González J. Ruiz-Jiménez M. D. Luque de Castro 《Journal of the American Oil Chemists' Society》2011,88(11):1737-1745
The oils produced from five olive cultivars (i.e. arbequina, gordal, manzanilla, picual and picudo) and the evolution of fatty
acid profile during olive fruit ripening were studied. The total oil content increased throughout ripening for Picudo cultivars;
however, all other cultivars reached maximum oil contents between ripeness stage 2 and 4. The content of trans (0.3–5.8%), saturated (8.3–21.4%), monounsaturated (41.9–84.1%) and polyunsaturated fatty acids (2.3–49.7%) varied with the
ripeness state and cultivar. Different trends of the different parameters were found as a function of the ripeness state and
the cultivar. Statistical analysis reveal that manzanilla drupes, at the different ripeness states, are clearly different
from the rest of the cultivars. In addition, there were no significant differences in the fatty acid profile of the oils obtained
from drupes at ripeness states between 2 and 4. 相似文献
12.
This study presents the FA composition and trans FA (TFA) contents of different hydrogenated vegetable oils and blended fats marketed in Pakistan. Thirty-four vanaspati (vegetable
ghee), 11 shortenings, and 11 margarines were analyzed. The contents of saturated FA, cis monounsaturated FA, and cis PUFA were in the following ranges: vanaspati 27.8–49.5, 22.2–27.5, 9.3–13.1%; vegetable shortenings 37.1–55.5, 15.8–36.0,
2.7–7.0%; and margarines 44.2–55.8, 21.7–39.9, 2.9–20.5%, respectively. Results showed significantly higher amounts of TFA
in vanaspati samples, from 14.2 to 34.3%. Shortenings contained TFA proportions of 7.3–31.7%. The contents of TFA in hard-type
margarines were in the range of 1.6–23.1%, whereas soft margarines contained less than 4.1% TFA. 相似文献
13.
M. Charef Mohamed Yousfi M. Saidi P. Stocker 《Journal of the American Oil Chemists' Society》2008,85(10):921-924
The fruits of two plants from Algeria (Quercus and Pistacia lentiscus) were investigated. The paper reports the chemical characteristics and the fatty acid composition of the oil extracts from
the fruits. The black fruits of P. lentiscus has the highest crude fat of 32.8%, followed by the red fruits with 11.7%, and the lowest value of 9% in Quercus (acorn). The acid value was highest in red fruits of P. lentiscus oil (24.0 mg KOH/g), followed by the black fruits oil and lowest in acorn oil. The relatively high iodine value in the oils
indicates the presence of many unsaturated bonds. Saponification value was highest in the Quercus ilex oil (166.7 mg KOH/g), while the lowest value was in the black fruits of P. lentiscus oil. Gas-liquid chromatography revealed that the three dominant fatty acids found are: palmitic C16:0 (16.3–19.5%), oleic
C18:1 (55.3–64.9%), linoleic C18:2 (17.6–28.4%). The oils contain an appreciable amount of unsaturated fatty acids (78.8–83.5%). 相似文献
14.
W. M. N. Ratnayake C. Gagnon L. Dumais W. Lillycrop L. Wong M. Meleta P. Calway 《Journal of the American Oil Chemists' Society》2007,84(9):817-825
Dietary trans fatty acids (TFA) are of major concern because of their adverse effects on blood lipid levels and coronary heart disease.
In Canada, margarines were significant sources of TFA during the 1980s and 1990s. However, this is expected to change with
increased public awareness over their adverse health effects and the introduction of new legislature to include TFA content
on the Nutritional Facts table of food labels. In this study, the TFA content of the top-selling 29 Canadian margarines, which
represented 96.3% of the market share, was determined by capillary gas-liquid chromatography in order to assess the influence
of regulatory development during the 3-year transition period between the announcement of new food labelling regulations in
Canada that require mandatory declaration of the trans fat content in most pre-packaged foods in January 2003 and its enforcement on 12 December 2005. The 29 margarines included
15 tub margarines made from non-hydrogenated vegetable oils (NHVO-tub margarines), 11 tub margarines made from partially hydrogenated
vegetable oils (PHVO-tub margarines) and three print margarines, which were also made from partially hydrogenated vegetable
oils (PHVO-print margarines). The 15 NHVO tub-margarines accounted for 71% of the total margarine market share and generally
contained less than 2% TFA (mean value 0.9 ± 0.3% of total fatty acids). The mean total TFA contents of PHVO-tub margarines
and PHVO-print margarines, were 20.0 ± 4.5% and 39.6 ± 3.5%, and their market shares were 19.3 and 6.0%, respectively. Although
during the last 10 years, increasing number of soft tub margarines that contained very little trans fats have been made available in Canada, the PHVO-tub- and -print margarines still contain high levels of trans fats similar to those margarines that were sold in the 1990s. The market share data suggest that the margarines prepared
using NHVO and containing almost no TFA were preferred by Canadians over those margarines prepared using PHVO, even before
the mandatory declaration of TFA content came into effect on 12 December 2005. 相似文献
15.
Sarojini J. K. A. Ubhayasekera Alba Tres Rafael Codony Paresh C. Dutta 《Journal of the American Oil Chemists' Society》2010,87(2):173-184
Chicken is the most widely consumed meat all over the world due to chickens being easy to rear, their fast growth rate and
the meat having good nutritional characteristics. The main objective of this paper was to study the effects of dietary fatty
by-products in low, medium and high levels of oxidized lipids and trans fatty acids (TFAs) on the contents of cholesterol and oxycholesterols in meat, liver, and plasma of chickens. A palm fatty
acid distillate, before and after hydrogenation, and a sunflower–olive oil blend (70/30, v/v) before and after use in a commercial
frying process were used in feeding trials after adding 6% of the fats to the feeds. Highly oxidized lipid and TFA feeds significantly
increased the contents of cholesterol and oxycholesterols in all tissues of chicken (0.01 < p ≤ 0.05). The contents of oxycholesterols in chicken meat, liver and plasma obtained from TFA feeding trials varied between
17 and 48 μg/100 g in meat, 19–42 μg/100 g in liver and 105–126 μg/dL in plasma. In contrast, in the oxidized lipid feeding
trials, oxycholesterols varied between 13 and 75 μg/100 g in meat, 30–58 μg/100 g in liver and 66–209 μg/dL in plasma. Meat
from chickens fed with feeds containing high levels of TFAs or oxidized lipids may contribute to higher ingestion of cholesterol
and oxycholesterols by humans. 相似文献
16.
Two gas chromatography (GC) procedures were compared for routine analysis of trans fatty acids (TFA) of vegetable margarines, one direct with a 100-m high-polarity column and the other using argentation thin-layer
chromatography and GC. There was no difference (P>0.05) in the total trans 18∶1 percentage of margarines with a medium level of TFA (∼18%) made using either of the procedures. Both methods offer good
repeatability for determination of total trans 18∶1 percentage. The recoveries of total trans isomers of 18∶1 were not influenced (P>0.1) by the method used. Fatty acid composition of 12 Spanish margarines was determined by the direct GC method. The total
contents of trans isomers of oleic, linoleic, and linolenic acids ranged from 0.15 to 20.21, from 0.24 to 0.99, and from 0 to 0.47%, respectively,
and the mean values were 8.18, 0.49, and 0.21%. The mean values for the ratios [cis-polyunsaturated/(saturated +TFA)] and [(cis-polyunsaturated + cis-monounsaturated)/(saturated +TFA)] were 1.25±0.39 and 1.92±0.43, respectively. Taking into account the annual per capita
consumption of vegetable margarine, the mean fat content of the margarines (63.5%), and the mean total TFA content (8.87%),
the daily per capita consumption of TFA from vegetable margarines by Spaniards was estimated at about 0.2 g/person/d. 相似文献
17.
Michael Lefevre Ronald P. Mensink Penny M. Kris-Etherton Barbara Petersen Kim Smith Brent D. Flickinger 《Lipids》2012,47(10):951-962
The varied functional requirements satisfied by trans fatty acid (TFA)—containing oils constrains the selection of alternative fats and oils for use as potential replacements in specific food applications. We aimed to model the effects of replacing TFA-containing partially hydrogenated soybean oil (PHSBO) with application-appropriate alternatives on population fatty acid intakes, plasma lipids, and cardiovascular disease (CVD) risk. Using the National Health and Nutrition Examination Survey 24-hour dietary recalls for 1999–2002, we selected 25 food categories, accounting for 86 % of soybean oil (SBO) and 79 % of TFA intake for replacement modeling. Before modeling, those in the middle quintile had a mean PHSBO TFA intake of 1.2 % of energy. PHSBO replacement in applications requiring thermal stability by either low-linolenic acid SBO or mid-oleic, low-linolenic acid SBO decreased TFA intake by 0.3 % of energy and predicted CVD risk by 0.7–0.8 %. PHSBO replacement in applications requiring functional properties with palm-based oils reduced TFA intake by 0.8 % of energy, increased palmitic acid intake by 1.0 % of energy, and reduced predicted CVD risk by 0.4 %, whereas replacement with fully hydrogenated interesterified SBO reduced TFA intake by 0.7 % of energy, increased stearic acid intake by 1.0 % of energy, and decreased predicted CVD risk by 1.2 %. PHSBO replacement in both thermal and functional applications reduced TFA intake by 1.0 % of energy and predicted CVD risk by 1.5 %. Based solely on changes in plasma lipids and lipoproteins, all PHSBO replacement models reduced estimated CVD risk, albeit less than previously reported using simpler replacement models. 相似文献
18.
Afaf Kamal-Eldin Lars Åke Appelqvist 《Journal of the American Oil Chemists' Society》1994,71(2):135-139
Seeds from different collections of cultivatedSesamum indicum Linn. and three related wild species [specifically,S. alatum Thonn.,S. radiatum Schum and Thonn. andS. angustifolium (Oliv.) Engl.] were studied for their oil content and fatty acid composition of the total lipids. The wild seeds contained
less oil (ca. 30%) than the cultivated seeds (ca. 50%). Lipids from all four species were comparable in their total fatty acid composition, with palmitic (8.2–12.7%), stearic
(5.6–9.1%), oleic (33.4–46.9%) and linoleic acid (33.2–48.4%) as the major acids. The total lipids from selected samples were
fractionated by thin-layer chromatography into five fractions: triacylglycerols (TAG; 80.3–88.9%), diacylglycerols (DAG; 6.5–10.4%),
free fatty acids (FFA; 1.2–5.1%), polar lipids (PL; 2.3–3.5%) and steryl esters (SE; 0.3–0.6%). Compared to the TAG, the four
other fractions (viz, DAG, FFA, PL and SE) were generally characterized by higher percentages of saturated acids, notably palmitic and stearic
acids, and lower percentages of linoleic and oleic acids in all species. Slightly higher percentages of long-chain fatty acids
(20∶0, 20∶1, 22∶0 and 24∶0) were observed for lipid classes other than TAG in all four species. Based on the fatty acid composition
of the total lipids and of the different acyl lipid classes, it seems thatS. radiatum andS. angustifolium are more related to each other than they are to the other two species. 相似文献
19.
M. M. Mossoba J. K. G. Kramer V. Milosevic M. Milosevic H. Azizian 《Journal of the American Oil Chemists' Society》2007,84(4):339-342
The mandate to label food products with the content of total trans fatty acids has led to an increase in demand for sensitive and accurate methodologies for the rapid quantitation of trans fats. Unfortunately, the latest official infrared (IR) spectroscopic method lacks the required sensitivity. A more sensitive
IR procedure that requires the measurement of the height of the second derivative (2D) of the trans absorption band at 966 cm−1 was recently proposed; however, a reported inconsistency at low trans levels between GC (0% of total fat) and IR (1.2% of total fat) results for a fully hydrogenated vegetable oil could not be
reconciled, and triggered further investigations. For the first time, we recognize and report the presence of weak interference
bands (962–956 cm−1) attributed to saturated fats in the IR spectra of trans fats; these interference bands have an adverse impact on the sensitivity and accuracy of the IR determination at low trans levels (≤0.5% of total fat). Therefore, weak spectral features observed at energies below the one expected for trans bands (966 cm−1) in test samples high in saturated fat (coconut oil and cocoa butter) must not be mistaken for trans bands. 相似文献
20.
Margarines and shortenings have been major contributors to the intake by humans of the probably atherogenic trans FA (TFA). In 1999, all 73 brands of margarines and shortenings on the Danish market were analyzed by GLC on a 50-m highly
polar capillary column, and the results were compared with similar investigations in 1992 and 1995. A gradual decline of TFA
in Danish margarines was observed. From 1992 to 1995, a reduction of TFA from 10.4 to 3.6% took place in margarines with 20–40%
linoleic acid. In 1999, TFA was practically absent in all the margarines, but it remained unchanged in shortenings, averaging
about 6–7%. Long-chain TFA from hydrogenated fish oil, although present in 13 brands in 1995, were not found at all in the
1999 samples. Trans-linoleic acids or CLA were not found. The reduction in TFA content in margarines has not resulted in a systematic change
over the years in the content of saturated FA, monounsaturated FA, or PUFA. Calculated from sales figures, the intake of TFA
decreased from 2.2 g per capita per year in 1992, to 1.5 g in 1995, and to 0.4 g in 1999. 相似文献