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1.
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
2.
Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil 总被引:1,自引:0,他引:1
One of the major difficulties in using crude vegetable oils as substitute fuels in diesel engines is their relatively high
viscosities. Increasing the temperature of the crude vegetable oil, blending it with diesel oil, or the combination of both
offers a simple and effective means of controlling and lowering the viscosities of vegetable oils. This work reports viscosity
data, determined with a rotational bob-and-cup viscometer, for crude palm oil and cononut oil blended with diesel oil over
the temperature range of 20–80°C and for different mixture compositions. All the test oil samples showed a time-independent
newtonian type of flow behavior. The reduction of viscosity with increasing liquid temperature followed an exponential relationship,
with the two constants of the equation being a function of the volume percentage of the vegetable oil in the mixture. A single
empirical equation was developed for predicting the viscosity of these fuel mixtures under varying temperatures and blend
compositions. 相似文献
3.
Jorge de A. Rodrigues Jr. Fabianne de P. Cardoso Elizabeth R. Lachter Luciana R. M. Estevão Edson Lima Regina S. V. Nascimento 《Journal of the American Oil Chemists' Society》2006,83(4):353-357
The influence of FA ester chemical structures on the rheology and crystallization temperature of those compounds was evaluated
using methyl, n-butyl, n-octyl, and 2-ethyl-1-hexyl FA esters with different chain lengths and different degrees of unsaturation. The rheological
properties were analyzed in a high-precision rheometer at various temperatures, and the crystallization temperatures were
determined by DSC. Esters produced from the esterification of pure FA and from the transesterification of vegetable oils (i.e.,
soybean, corn, linseed, and babassu coconut oils) were evaluated. The length of the FA chain was shown to have a marked influence
on the viscosity and crystallization temperature of the systems, whereas branching affected only the crystallization temperature
to a significant extent. The viscosity and crystallization temperature of the systems were also influenced by the degree of
unsaturation. One double bond was shown to increase viscosity, whereas two or three double bonds caused a decrease in the
viscosity of the systems. Unsaturation lowered the crystallization temperature in all cases, regardless of the number of double
bonds. From all the oils studied, methyl esters from babassu coconut oil presented the lowest crystallization temperatures. 相似文献
4.
Physical and Chemical Characterizations of Normal and High-Oleic Oils from Nine Commercial Cultivars of Peanut 总被引:1,自引:0,他引:1
J. P. Davis L. O. Dean W. H. Faircloth T. H. Sanders 《Journal of the American Oil Chemists' Society》2008,85(3):235-243
Density and viscosity data as a function of temperature (5–100 °C) were collected for oils (normal and high-oleic) from nine
cultivars of peanut. Density decreased linearly (R
2 ≥ 0.99) with increasing temperature for all oils, whereas viscosity (dynamic or kinematic) decreased exponentially with increasing
temperature. At any particular temperature, dynamic viscosity increased linearly (R
2
≥ 0.95) with decreasing oil density among the various oils. Slopes of the linear fits (with units of kinematic viscosity)
for dynamic viscosity versus density plots decreased in an exponential fashion as the measurement temperature decreased. High-oleic
oils had both the lowest densities and highest viscosities, with viscosity differences being most apparent at cooler temperatures.
Increasing contents of oleic acid, decreasing contents of linoleic acid, and decreasing contents of palmitic acid were each
associated with decreased density and increased viscosity among the oils. Two of the three high-oleic oils had the significantly
(p < 0.05) highest content of total tocopherols, while the other high-oleic oil was statistically grouped with the oils having
the 2nd highest total tocopherol content. This suggests a link between increased total tocopherols and high-oleic peanut oils;
however, no obvious linear correlations were observed in tocopherol content and oil physical properties (density or viscosity).
The use of trade names in this publication does not imply endorsement by the United States Department of Agriculture-Agricultural
Research Service. 相似文献
5.
Ayhan Demirbas 《Fuel》2008,87(8-9):1743-1748
The aim of this study was to estimate mathematical relationships between higher heating value (HHV) and viscosity, density or flash point measurements of various biodiesel fuels. The HHV is an important property defining the energy content and thereby efficiency of fuels, such as vegetable oils and biodiesels. The biodiesels were characterized for their physical and main fuel properties including viscosity, density, flash point and higher heating value. The viscosities of biodiesels (2.8–5.1 mm2/s or cSt at 311 K) were much less than those of pure oils (23–53 mm2/s at 311 K), and their HHVs of approximately 41 MJ/kg were 10% less than those of petrodiesel fules (~46 MJ/kg). Compared to No. 2 diesel fuel, all of the vegetable oil methyl esters were slightly viscous. The density and flash point values of vegetable oil methyl esters are highly lower than those of vegetable oils. The HHVs of vegetable oils and their biodiesels were measured and correlated using linear least square regression analysis. There is high regression between viscosity and higher heating value for vegetable oil and biodiesel samples. An increase in density from 848 to 885 g/L for biodiesels increases the viscosity from 2.8 to 5.1 cSt and the increases are highly regular. There is high regression between density and viscosity values vegetable oil methyl esters. The relationships between viscosity and flash point for vegetable oil methyl esters are considerably regular. 相似文献
6.
Jean‐Philippe Bonnet Laurie Devesvre Jacques Artaud Philippe Moulin 《European Journal of Lipid Science and Technology》2011,113(8):1019-1025
Knowledge of the viscosity of virgin olive oils (VOOs) is of great importance for the design of pilot plants, to determine the time required for the settling of particles at the end of the production chain and from a sensory view point. The dynamic viscosities of French VOOs from four different cultivars (‘Aglandau’, ‘Bouteillan’, ‘Salonenque’ and ‘Tanche’) were studied as a function of their fatty acid and TAG compositions and of the temperature [10–50°C]. These four VOOs had different TAG and fatty acid compositions representative of the range of compositional variations in the main French oils. Their viscosities were similar, although small but measurable differences that depended on their compositions were apparent. All the VOO samples exhibited the same dynamic viscosity pattern over temperature. For a given temperature, the viscosity difference was the greatest between Aglandau and Salonenque oils, Aglandau being the oil with the highest viscosity. The correlation between temperature and viscosity was highlighted by an Arrhenius model for this Newtonian fluid. The Arrhenius activation energy was correlated (R2 = 0.993) with the percentage of triolein, the main TAG in olive oil. 相似文献
7.
Rapid FT-NIR Analysis of Edible Oils for Total SFA, MUFA, PUFA, and Trans FA with Comparison to GC 总被引:1,自引:0,他引:1
Magdi M. Mossoba Hormoz Azizian Cynthia Tyburczy John K. G. Kramer Pierluigi Delmonte Ali-Reza Fardin Kia Jeanne I. Rader 《Journal of the American Oil Chemists' Society》2013,90(6):757-770
Declarations of the total content of trans fatty acids (FA) and saturated FA (SFA) are mandatory on food labels in the US and Canada. Gas chromatography (GC) has been the method of choice for the determination of FA composition. However, GC is time consuming and requires conversion of fats and oils to their FA methyl esters. In the present study, a recently published Fourier transform near-infrared (FT-NIR) spectroscopic procedure was applied to the rapid (<5 min) determination of total SFA, monounsaturated FA (MUFA), polyunsaturated FA (PUFA), and trans FA contents of 30 commercially available edible fats and oils. Good agreement was obtained between the GC and FT-NIR methods for the determination of total SFA, MUFA, and PUFA contents. Differences between the two methods were apparent for the determination of trans fat at trans fat levels <2 % of total fat. The analytical determinations of total SFA, MUFA, and PUFA contents for many of the oils examined differed from the respective values declared on the product labels. Our findings demonstrate that the FT-NIR procedure serves as a suitable alternative method for the rapid determination of total SFA, MUFA, PUFA and trans FA contents of neat vegetable oils. 相似文献
8.
A rapid method was developed for classifying and quantifying the FA composition of edible oils and fats using Fourier Transform
near infrared spectroscopy (FT-NIR). The FT-NIR spectra showed unique fingerprints for saturated FA, cis and trans monounsaturated FA, and all n−6 and n−3 PUFA within TAG to permit qualitative and quantitative comparisons of fats and oils.
The quantitative models were based on incorporating accurate GC data of the different fats and oils and FT-NIR spectral information
into the calibration model using chemometric analysis. FT-NIR classification models were developed based on chemometric analyses
of 55 fats, oils, and fat/oil mixtures that were used in the identification of similar materials. This database was used to
prepare three calibration models—one suitable for the analysis of common fats and oils with low levels of trans FA, and the other two for fats and oils with intermediate and high levels of trans FA. The FT-NIR method showed great potential to provide the complete FA composition of unknown fats and oils in minutes.
Compared with the official GC method, the FT-NIR method analyzed fats and oils directly in their neat form and required no
derivatization of the fats to volatile FAME, followed by time-consuming GC separations and analyses. The FT-NIR method also
compared well with the official FTIR method using an attenuated total reflectance (ATR) cell; the latter provided only quantification
of specific functional groups, such as the total trans FA content, whereas FT-NIR provided the complete FA profile. The FT-NIR method has the potential to be used for rapid screening
and/or monitoring of fat products, trans FA determinations for regulatory labeling purposes, and detection of contaminants. The quantitative FT-NIR results for various
edible oils and fats and their mixtures are presented based on the FT-NIR model developed. 相似文献
9.
Kanika Sharma Manoj Kumar Jose M. Lorenzo Sanjay Guleria Sujata Saxena 《Journal of the American Oil Chemists' Society》2023,100(1):5-24
Modification of vegetable oils is carried out to make them suitable according to their specific end use as most of the vegetable oils in original forms do not meet the recommended dietary allowance of saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. Vegetable oils are modified using a variety of techniques including hydrogenation, interesterification, fractionation, and blending. However, blending is the most widely accepted method for improving the physicochemical properties, nutritive value and oxidative stability of vegetable oils because it is simple, cost-effective, non-destructive, and does not involve chemical treatments. Blending vegetable oils with contrasting fatty acid compositions or blending omega 3 fatty acids and antioxidants rich minor oils with major oils are two common strategies to formulate blends. Blended oil with balanced fatty acids could play substantial role in improving the consumers' health. However, while designing vegetable oil blends, it is important to keep in mind the intended application of the formulated blend, consumer's demands and also food laws. This review paper covers the literature related to blending of vegetable oils with a focus on effect of vegetable oils blending on their physicochemical and nutritional properties, health benefits and utility in food industries. 相似文献
10.
Maysa Teixeira Resende Salvatore Campisi-Pinto Charles Linder Zeev Wiesman 《Journal of the American Oil Chemists' Society》2019,96(2):125-135
Polyunsaturated fatty acids (PUFA) are components of many commercial products such as edible oils, foods, cosmetics, medication, and in biological systems such as phospholipids of cellular membranes. Although PUFA aggregates are important functional components, they are also related to system degradation, because PUFA are susceptible to oxidation via their multiple double bonds and allylic carbons. Current technologies are not effective in characterizing the morphological and chemical structural domains of saturated, monounsaturated fatty acids (MUFA) and PUFA materials, or how the morphological structures of fatty acids, at the mesomolecular, nanomolecular, and molecular levels, affect their oxidation mechanisms. In this article, the 1H low-field (LF) NMR energy relaxation time technology is proposed as a tool to analyze PUFA oils undergoing thermal oxidation. This technology generates two-dimensional (2D) chemical and morphological spectra using a primal-dual interior method for the convex objectives (PDCO) optimization solver for computational processing of the energy relaxation time signals T1 (spin–lattice) and T2 (spin–spin). The 2D graphical maps of T1 vs. T2 generated for butter, rapeseed oil, soybean oil, and linseed oil show that the different degrees of unsaturation of fatty-acid oils affect their chemical and morphological domains, which influences their oxidative propensity. The technology of the 1H LF-NMR energy relaxation time proved to be an effective tool to characterize and monitor PUFA oxidation. 相似文献
11.
Crude enzyme isolate was prepared from the intestine of rainbow trout. Positional specificity of the crude enzyme isolate
was determined from both 1(3)- and 2-MAG products after in vitro lipolysis of radioactive-labeled triolein. The ratio of 2-MAG/1(3)-MAG was 2∶1, suggesting that the overall lipase specificity
of the enzyme isolate from rainbow trout tended to be 1,3-specific; however, activity against the sn-2 position also was shown. In vitro lipolysis of four different unlabeled oils was performed with the crude enzyme isolate. The oils were: structured lipid [SL;
containing the medium-chain FA (MCFA) 8∶0 in the sn-1,3 positions and long-chain FA (LCFA) in the sn-2 position], DAG oil (mainly 1,3-DAG), fish oil (FO), and triolein (TO). MCFA were rapidly hydrolyzed from the SL oil. LCFA
including n−3 PUFA were, however, preserved in the sn-2 position and therefore found in higher amounts in 2-MAG of SL compared with 2-MAG of FO, DAG, and TO. Lipolysis of the
DAG oil produced higher amounts of MAG than the TAG oils, and 1(3)-MAG mainly was observed after lipolysis of the DAG oil.
The positional specificity determined and the results from the hydrolysis of the different oils suggest that n−3 very long-chain
PUFA from structured oils may be used better by aquacultured fish than that from fish oils. 相似文献
12.
Weiguo Lang Shahab Sokhansanj Frank W. Sosulski 《Journal of the American Oil Chemists' Society》1992,69(10):1054-1055
Viscosities of refined, bleached, deodorized (RBD) and refined, bleached, winterized (RBW) canola oils were measured at temperatures
from 4 to 100°C. The viscosities of these refined canola oils were exponentially related to the oil temperature. Viscosity
of the RBW oil was slightly greater than that of the RBD oil when the temperature was below 15°C. Compared to refined soybean
oil, the canola oils were substantially more viscous. The viscosity of canola oil was modelled asv = exp(C0 + C1T + C2T2). The maximum predicted error was less than 1.6% over the tested temperature range. 相似文献
13.
Dietary trans fatty acids: Review of recent human studies and food industry responses 总被引:4,自引:0,他引:4
Dietary trans FA at sufficiently high levels have been found to increase low density lipoprotein (LDL)-cholesterol and decrease high density
lipoprotein (HDL)-cholesterol (and thus to increase the ratio of LDL-cholesterol/HDL-cholesterol) compared with diets high
in cis monounsaturated FA or PUFA. The dietary levels of trans FA at which these effects are easily measured are around 4% of energy or higher to increase LDL-cholesterol and around 5
to 6% of energy or higher to decrease HDL-cholesterol, compared with essentially trans-free control diets. Very limited data at lower levels of intake (less than 4% of energy) are available. Most health professional
organizations and some govemments now recommend reduced consumption of foods containing trans FA, and effective January 1, 2006, the U.S. Food and Drug Administration requires the labeling of the amounts of trans FA fer serving in packaged foods. In response, the food industry is working on ways to eliminate or greatly reduce trans FA in food products. Current efforts focus on four technological options: (i) modification of the hydrogenation process,
(ii) use of interesterification, (iii) use of fractions high in solids from natural oils, and (iv) use of trait-enhanced oils.
Challenges to the food industry in replacing trans FA in foods are to develop formulation options that provide equivalent functionality, are economically feasible, and do not
greatly increase saturated FA content. 相似文献
14.
Rheological and thermal properties of five soybean oils with modified FA compositions were studied. Viscosity decreased with
increasing temperature at different rates for the different oils. Oil with a high-oleic acid content had higher viscosity
and a greater rate of change than did oils with typical FA compositions, oil with low-saturated FA or low-linolenic acid content,
or oil from lipoxygenase-free soybeans. The melting and crystallization behaviors of the oils were examined using DSC. The
high-oleic acid oil and the oil with low-saturated FA content had different DSC profiles compared with the other oils. Specific
heat capacities of oils were estimated using a mathematical model; the high-oleic acid oil had a higher specific heat value,
and the low-saturated FA oil had a lower value than did the other oils. 相似文献
15.
George J. Piazza Thomas A. Foglia 《Journal of the American Oil Chemists' Society》2006,83(12):1021-1025
In our previous work we used ground oat (Avena sativa) seeds as an inexpensive source of enzymes for the modification of FA or their chemical derivatives. We have extended this
work by observing the products derived from an intact fat and three vegetable oils through the concerted action of oat seed
enzymes. A modified reversed-phase HPLC protocol was devised that allowed the quantification of FFA, epoxy FA, and acylglycerols
without derivatization. It was found that the addition of the surfactant deoxycholate or calcium chloride was needed to observe
best hydrolysis of TAG to FA. Without an added oxidant, lipase action produced up to 80% by weight of FA at pH 7–9 with small
amounts of DAG and MAG. When the oxidant t-butyl hydroperoxide was added in the presence of deoxycholate, the FA were partially converted to epoxide derivatives (up
to 35% by weight). When calcium chloride replaced deoxycholate, only 4% by weight of the product was epoxide derivatives.
The highest levels of FA epoxides were generated at pH7, and up to 15% by weight of the product at this pH was epoxymonostearin
(monoepoxyoctadecanoylglycerol). The optimal molar amount of t-butyl hydroperoxide to add with deoxycholate for high epoxide formation was 1.4 to 2.8 times the amount of fatty esters in
soybean oil. In no instance were oxidized DAG or TAG detected, demonstrating that a highly specific enzymatic process was
responsible for epoxide formation. The epoxide products may be used to produce polyols with high viscosity for grease preparations. 相似文献
16.
Viscosity estimation of triacylglycerols and of some vegetable oils, based on their triacylglycerol composition 总被引:1,自引:0,他引:1
M. Noor Azian A. A. Mustafa Kamal F. Panau W. K. Ten 《Journal of the American Oil Chemists' Society》2001,78(10):1001-1005
The experimentally determined kinematic viscosities of simple triacylglycerols [trilaurin, trimyristin (MMM), tripalmitin
(PPP), tristearin (SSS), triolein (OOO), and trilinolein (LiLiLi) were correlated to a modified Andrade-type equation. The
constants for the modified equation were derived for each simple triacylglycerol. The method was also used to estimate the
viscosity of mixed triacylglycerols [1,2-dimyristoyl-3-palmitoyl (MMP), 1,2-dioleoyl-3-palmitoyl (OOP), 1,2-dimyristoyl-3-oleoyl
(MMO), and 1,2-dipalmitoyl-3-oleoyl (PPO)], binary triacylglycerol mixtures (PPO/OOP, PPP/SSS, and OOO/SSS of different portions),
and three types of vegetable oils [refined, bleached, and deodorized palm oil; cocoa butter; and canola oil] by applying modified
Kay’s rule utilizing the simple triacylglycerol constants derived earlier. In all cases, the estimated values for liquid viscosity
were compared with experimental values determined in this work and with previous work from the literature. When applied to
vegetable oils, the method requires knowledge of their triacylglycerol composition. Despite its simplicity, the method gives
a reasonable estimate. The method may be used to predict the viscosity of different blends of vegetable oils, and the accuracy
is expected to increase when more experimental data on simple triacylglycerols become available. 相似文献
17.
Borage oil sterols were isolated by TLC and characterized using GC and GC-MS. Several diunsaturated Δ5-sterols, some of them not previously recorded in vegetable oils, were found. Of these, 24-methylcholesta-5,23-dienol and
24-ethylcholesta-5,23-dienol could be useful markers for borage oil. Two other diunsaturated Δ5-sterols that are rarely found in vegetable oils, 24-methylcholesta-5,24(25)-dienol and 24-ethylcholesta-5,24(25)-dienol,
were identified. The diunsaturated C-24(28)-sterol, isofucosterol, was also found, as well as the monounsaturated Δ5-sterols campesterol and sitosterol. These are normally present in vegetable oils, which makes them unsuitable as markers
for borage oil. 相似文献
18.
The suitability of a recently proposed method based on ethanolysis with immobilized Candida antarctica lipase for regiospecific analysis of oils containing long-chain PUFA such as [PA and DHA has been evaluated using selected
marine oils and regio-isomerically enriched synthetic TAG substrates. 1,3-Regios-electivity of the lipase was enhanced when
the ethanolysis was conducted in a high excess of ethanol, typically 10–50 times by weight of the oil. This enabled the reaction
to be conducted on a milligram scale. However, irrespective of the ethanol-to-oil ratio, C. antarctica lipase released FA from TAG at different rates depending on the degree of unsaturation and/or chain length of the FA. Differences
in lipolysis rates were particularly significant for EPA and DHA, with EPA released faster than DHA. Although DHA can be measured
with reasonable accuracy by ethanolysis with C. antarctica, the method requires further optimization before it can be adopted for reliable regiospecific analyses that are as accurate
as those obtainable by 13C NMR analysis for all major FA occurring in oils rich in long-chain PUFA. 相似文献
19.
Physicochemical and instrumental characterization of rubber (Hevea brasiliensis Müll. Arg.) seed oil (RSO) was carried out for the purposes of quality assessment, identification, and authentication. Properties
such as color (Lovibond), specific gravity, percent FFA (as oleic acid), acid value, saponification value, iodine value, and
viscosity were determined. FA composition and M.W. averages of RSO were determined using GLC and gel permeation chromatography
(GPC), respectively. Structural features of RSO were also determined using FTIR, 1H NMR, and 13C NMR spectroscopy. The natural form of RSO is highly acidic (acid value≈43.6 mg KOH/g). The saturated FA are palmitic (17.50%)
and stearic (4.82%), and the main unsaturated FA are oleic (25.33%), linoleic (37.50%), and linolenic (14.21%). The oil can
be classified as semidrying. GPC shows an unusual peak that is due to a very high M.W. (≈38,800) fraction that is not found
in the chromatogram of known vegetable oils and is therefore unique to RSO. FTIR, 1H NMR, and 13C NMR analyses confirmed that RSO is composed mainly of TAG of saturated and unsaturated FA. Functional groups such as carbonyl,
olefinic unsaturation, esters, glyceryl, methylene, and terminal methyl that are present in vegetable oils are also present
in RSO. 相似文献
20.
Ali Moayedi Karamatollah Rezaei Sohrab Moini Behnam Keshavarz 《Journal of the American Oil Chemists' Society》2011,88(4):503-508
Chemical compositions of oils extracted from three wild almond species [Amygdalus scoparia from Beyza, Iran (AZ); A. scoparia from Borazjan, Iran (AJ), and A. hausknechtii from the Firuzabad region, (AH)] and a domestic species, A. dulcis from Estahban, Iran (AD), as a reference, were investigated. Total oil content ranged from 44.4% in AJ to 51.4% in AD. Saponification
numbers were in the range of 173.5 (for AJ) to 192.9 for AD. Oxidative stability, total phenolic contents and total wax contents
were found to be within the ranges 11.7–14.0 h, 33.9–43.2 and 2.05–2.53%, respectively. The main monounsaturated fatty acid
(MUFA) was oleic acid ranging from 66.7% for AH to 69.7% for AZ. The only polyunsaturated fatty acid (PUFA) was linoleic acid
ranging from 18.2% for AZ to 23.0% for AD. The major saturated fatty acid was palmitic acid. MUFA contents and MUFA to PUFA
ratio in the oils from wild almond species as well as those in the domestic one were found at higher levels than those in
the common vegetable oils such as soybean, various nut oils, and also those from the seeds of pomegranate, grape, date and
sesame. Oils from wild almond species investigated here are rich in oleic acid and can be considered as potential vegetable
oils in the human diet. 相似文献