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1.
Noor Lida Habi Mat Dian Kalyana Sundram Nor Aini Idris 《European Journal of Lipid Science and Technology》2007,109(2):147-156
Palm stearin (POs) with an iodine value of 41.4, sunflower oil (SFO) and palm kernel olein (PKOo) were blended in various ratios according to a three‐component mixture design and subjected to chemical interesterification (CIE). Triacylglycerol (TAG) and solid fat content (SFC) profiles of the chemically interesterified (CIEed) blends were analyzed and compared with those of the corresponding non‐CIEed blends. Upon CIE, extensive rearrangement of fatty acids (FA) among TAG was evident. The concentrations of several TAG were increased, some decreased and several new TAG might also have been formed. The changes in the TAG profiles were reflected in the SFC profiles of the blends. The SFC of the CIEed blends, except the binary blends of POs/PKOo which experienced an increase in SFC following CIE, revealed that they were softer than their respective starting blends. Randomization of FA distribution within and among TAG molecules of POs and PKOo led to a modification in TAG composition of the POs/PKOo blends and improved miscibility between the two fats, and consequently diminished the eutectic interaction that occurred between POs and PKOo. 相似文献
2.
M. L. Herrera C. Falabella M. Melgarejo M. C. Añón 《Journal of the American Oil Chemists' Society》1999,76(1):1-6
Isothermal crystallization of sunflower seed oil hydrogenated under two different conditions was studied by means of pulse
nuclear magnetic resonance (pNMR) and optical microscopy. Solid fat content (SFC) curves showed two different shapes depending
on supercooling. When supercooling was high, hyperbolic curves were found, whereas with low supercooling sigmoidal curves
were obtained. Curves were interpreted with the modified Avrami equation. Photographs of the crystals were taken from the
beginning of crystallization, every 15 s until 15 min and every 5 min until 60 min. Samples which exhibited hyperbolic curves
showed a slight increase in crystal number, and crystals were needle-shaped in all cases. Samples which had sigmoidal crystallization
curves showed a marked increase in crystal number with time, and crystals were spherical in shape. Crystallization behavior
was also in agreement with the chemical composition of the samples. Samples which had the highest content of high-melting
triacylglycerols (especially trielaidin) showed only hyperbolic curves. Supercooling is a very important parameter that defines
the way nucleation occurs. Depending on the initial number of nuclei, two different growth mechanisms were found: a uniform
linear growth of the nuclei for a small initial number (sigmoidal curves) and an aggregate of the nuclei for a high initial
number (hyperbolic curves). 相似文献
3.
Hermanus Martinus Schaink 《Journal of the American Oil Chemists' Society》2023,100(12):929-944
Vegetable fats are complex multi-component mixtures of triglycerides. Here, the solidification behavior of a few vegetable fats is calculated using the Hildebrand equation. This calculation assumes, in the liquid phase, ideal mixing of the different components, in combination with literature data about the temperatures and enthalpies of fusion of the individual triglycerides. It further assumes a decomposition of the triglyceride blend into binary blends dissolved in an inert solvent. The solid fat content is calculated as function of the temperature, for only all α and only β and only β ' crystal modifications. The minor triglyceride components are explicitly included in the calculation. The calculated solid fat contents for cocoa butter, palm oil, inter-esterified palm oil and palm kernel olein oil are compared to pNMR data, reported in the literature. The standard deviations between calculated and experimental solid fat content lie between 4% and 14%. Temperature ranges are found, in which specific crystal modifications match to the pNMR data for the solid fat content. These temperature ranges are found to be consistent with literature data obtained using x-ray diffraction. As a by-product, the calculation presented here, enables the construction of scenarios that describe which triglyceride solidifies in which temperature interval. 相似文献
4.
H. M. D. Noor Lida K. Sundram W. L. Siew A. Aminah S. Mamot 《Journal of the American Oil Chemists' Society》2002,79(11):1137-1144
Modification of the characteristics of palm oil (PO), sunflower oil, and plam kernel olein (PKOo) according to conventional
three-component mixture designs was undertaken by a combination of blending and chemical interesterification (CIE) techniques.
TAG composition and solid fat content (SFC) profile of the starting blends were analyzed and compared with those of the interesterified
blends. Upon CIE, extensive rearrangement of FA among TAG was evident. Concentrations of several TAG were increased, some
were decreased, and several new TAG were formed. The resulting changes in TAG profile were reflected in the SFC of the blends.
The SFC values of the chemically interesterified blends, except binary blends of PO/PKOo, revealed that they were softer than
their respective starting blends. SFC data also indicated that eutectic interaction occurred between PO and PKOo in the starting
blends and that this interaction was diminished after CIE. 相似文献
5.
Wai-Lin Siew Chiew-Let Chong Yew-Ai Tan 《Journal of the American Oil Chemists' Society》1995,72(12):1587-1589
The composition of oil from the outer, middle, and inner section of palm kernel had been evaluated by gas-liquid chromatography
and nuclear magnetic resonance techniques. The composition was not homogenous throughout the kernel and was found to be more
unsaturated in the outer kernel. The inner core of the kernel is less unsaturated, having a higher lauric content. The variation
in the iodine value from the outer to inner section of the kernel suggested that composition of palm kernel oil was affected
by the kernel size. This was found to be true, as small kernels tend to have oil with higher iodine value than do larger kernels. 相似文献
6.
Similar physical characteristics but distinguishable sn‐2 palmitic acid content and reduced solid fat content of chemically interesterified palm olein compared with native palm olein by dry fractionation: A lab‐scale study 下载免费PDF全文
Shuen‐Yeing Mo Kim‐Tiu Teng Kalanithi Nesaretnam Oi‐Ming Lai 《European Journal of Lipid Science and Technology》2016,118(9):1389-1398
7.
W. L. Ng 《Journal of the American Oil Chemists' Society》1990,67(11):879-882
Nucleation from a supercooled melt of palm oil was studied by optical microscopy and differential scanning calorimetry (DSC).
Despite being a multicomponent system, palm oil exhibits a rather simple cooling thermogram with its high- and low-T exotherms
exclusively related to the “hard” and “soft” components of the oil. As the “hard” components are being removed, the position
of the high-T peak shifts down toward the low-T peak with diminishing peak intensity, while the position of the latter remains
virtually unchanged.
At 288°K, nucleation in a palm oil melt is instantaneous. Its induction time-temperature curve shows an abrupt discontinuity
at 297°K, which demarcates the occurrence of one polymorph from another. Nucleation data fit very well into the Fisher-Turnbull
equation. Its larger activation free energy of nucleation is accompanied by lowering of the melting point and an increase
in the crystal/melt interfacial free energy as compared to palm stearin. The slow rate of nucleation in palm oil is attributed
to intermolecular interaction between its “hard” and “soft” components.
Partly presented at the 1989 PORIM International Palm Oil Development Conference, September 5–9, Kuala Lumpur, Malaysia. 相似文献
8.
Salwa Bornaz Jacques Fanni Michel Parmentier 《Journal of the American Oil Chemists' Society》1994,71(12):1373-1380
Three ways have been undertaken to modify solid fat content of butter oil: (i) interesterification, (ii) adjunction of high-melting
glycerides and (iii) joint effect of adjunction of high-melting glycerides and interesterification. A solvent-free interesterification,
carried out with 1,3-specific lipase fromMucor miehei, resulted in an increase of the solid fat content (SFC) by about 114% after 48 h of interesterification. The changes in triglyceride
composition induced by this method were followed by quantitative determination of triglycerides of different equivalent carbon
number (ECN) and different theoretical carbon number. The major changes in the triglyceride composition occurred mainly in
the concentration of three groups of triglycerides with the same ECN (ECN=38). Adding high-melting glycerides trimyristin
(MMM) and tripalmitin (PPP) led to an increase of the SFC measured at 20°C as these proportions increased in the mixture.
The joint effect of the addition of MMM or PPP and interesterification was quite significant, mainly for triglycerides that
included myristic and palmitic acids. As far as the increase of SFC is concerned, the effect of interesterification decreases
when both substrate amounts increase. 相似文献
9.
The effects of enzymatic transesterification on the melting behavior of palm stearin and palm olein, each blended separately
with flaxseed oil in the ratio of 90∶10 and catalyzed by various types of lipases, were studied. The commercial lipases used
were Lipozyme IM, Novozyme 435, and myceliumbound lipases of Aspergillus flavus and A. oryzae. The slip melting point (SMP) of the palm stearin/flaxseed oil (PS/FS) mixture transesterified with lipases decreased, with
the highest drop noted for the mixture transesterified with Lipozyme IM. However, when palm stearin was replaced with palm
olein, the SMP of the palm olein/flaxseed oil (PO/FS) mixture increased, with the commercial lipases causing an increase of
41 to 48% compared to the nontransesterified material. As expected, the solid fat content (SFC) of the transesterified PS/FS
was lower at all temperatures than that of the nontransesterified PS/FS sample. In contrast, all transesterified PO/FS increased
in SFC, particularly at 10°C. Results from DSc and HPLC analyses showed that the high-melting glycerides, especially the tripalmitin
of palm stearin, were hydrolyzed. Consequently, 1,3-dipalmitoylglycerol was found to accumulate in the mixture. There was
no difference in the FA compositions between the transesterified and nontransesterified mixtures. 相似文献
10.
Dispersions of coating fat in corn oil (2.5–12.5 wt%) were prepared following two different protocols: Type A dispersions
had an average crystal size of 30–36 μm, whereas type B dispersions were less than 1 μm. In both dispersions the fat crystals
were aggregated into larger structures (up to 80 μm). The longitudinal ultrasonic properties (i.e., velocity, attenuation,
and reflectance) were linearly related to the solid fat content, but only attenuation was sensitive to the different microstructures.
The velocity and reflectance measurements were modeled using the Urick equation. Shear ultrasonic reflectance and oscillatory
viscometry were used to measure the dynamic viscosity of all dispersions. According to both methods, type B samples were always
more viscous than type A at a similar solids content. The correlation between the two techniques was good (r
2>0.99), but the numeric agreement was different for both systems. 相似文献
11.
A quantitative relationship between slip melting point (SMP) of palm kernel oil and pulsed nuclear magnetic resonance (NMR)
data was established. Regression analysis on the SMP and solid fat content (SFC) data by NMR afforded the following relationship:
SMP (°C) = 0.03278 X (SFC 10) + 0.1458 X (SFC 20) + 19.1738 where SFC 10 was the solid fat content (%) at 10°C and SFC 20
was the solid fat content (%) at 20°C. The coefficient of multiple correlation was 0.87871. The equation was tested with 12
samples of crude and refined palm kernel oil. SMPs as determined indirectly by NMR correlated well with the conventional open
capillary tube results (r = 0.99998). The maximum difference observed was 0.3°C. The correlation can be applied usefully for
quality control. 相似文献
12.
13.
G. Lakshminarayana M. M. Paulose B. Vishwanadham J. Laxminarayana P. A. Ramalingaswamy 《Journal of the American Oil Chemists' Society》1991,68(3):179-182
A single step process has been developed on a pilot plant scale (15 kg/batch) for simultaneous hydrogenation and dehydration
of castor oil using nickel catalyst and attapulgite to yield solid fats having a hydroxyl value of 7–33 and an iodine value
of 41–56. The polymer and keto fatty acid contents in the products were up to 2% and 3.2%, respectively. The product can be
used in the manufacture of soap as the hard fat component and in textile sizing. 相似文献
14.
Margarines made from refined, bleached, and deodorized palm oil at different emulsion temperatures showed no significant difference
in their consistency, polymorphic behavior, and solid fat content (SFC) during storage, although differences were observed
during processing. The emulsion temperatures studied were 40, 45, and 50°C, with other parameters such as emulsion flow rates,
tube cooler temperature, and pin rotor speed kept constant. The SFC developed during processing and storage at 28°C was measured
to evaluate the quality of margarine. The emulsion contained no SFC at any emulsion temperature studied. However, the amount
of SFC in the perfector or tube cooler unit increased to 15.9, 13.9, and 15.6% in margarine produced at emulsion temperatures
of 40, 45, and 50°C, respectively. At 40°C, the lowest SFC was developed during storage even though this margarine had the
highest consistency. The softening point of this sample was moderately high and closely related to the type of crystal developed,
which was a mixture of β′ and β crystals. Emulsion at 45°C gave the most stable margarine consistency and SFC with crystal
in the β′ form even after the fourth week. At 50°C, moderately soft product was produced, which might be undesirable for some
applications, although the crystals were in the β′ form. 相似文献
15.
Sabine Braipson-Danthine Claude Deroanne 《Journal of the American Oil Chemists' Society》2006,83(7):571-581
Several oils and fats often used for the industrial preparation of European shortenings were blended in binary systems. The
equilibrium (after 48 h at 15°C) solid fat contents (SFC; determined by pulsed NMR spectroscopy) were measured and plotted
against blend composition. SFC of the blends resulted from the SFC of each fat for the considered temperature as well as the
type of interaction existing between those fats (namely, ideal behavior, monotectic interaction, eutectic interaction, and
so on). The type of relationship fitted was dependent on the kind of interaction: Linear relationships were found for total
compatibility between fats, and polynomial-type (order 2) relationships were found for fats exhibiting incompatibility. Some
corresponding ternary oils and fats blends were also prepared and analyzed. Selected relationships (regression equations of
the fitted curves) obtained for binary blends were combined in order to calculate the SFC of the corresponding ternary blends.
Experimental values were generally close to predicted ones. The representation of SFC as a function of composition is interesting
as it allows one to determine rapidly and easily the type of molecular interaction between two fats and also to determine
equations that can be combined to calculate easily the SFC of corresponding ternary blends crystallized in the same way with
a good accuracy. The texture (hardness) of several binary and ternary blends was also measured. The combination of the results
obtained for SFC with the results obtained for the hardness of binary blends allows the prediction of the hardness of a corresponding
ternary blend under the same conditions. 相似文献
16.
A simple, rapid, and direct Fourier transform infrared (FTIR) spectroscopic method was developed for the determination of
moisture content of crude palm oil (CPO). The calibration set was prepared by adding double-distilled water to dried CPO in
ratios (w/w) between 0 and 13% moisture. A partial least squares (PLS) regression technique was employed to construct a calibration
model followed by cross-validation step. The accuracy of this method was comparable to the accuracy of the American Oil Chemists'
Society's vacuum oven method, which is used for determination of moisture and volatile matter, with mean difference (MDa) of 0.0105, a coefficient of determination (R
2) and a standard error of calibration (SEC) of 0.9781 and 0.91, respectively. It is also comparable to the accuracy of the
International Union of Pure and Applied Chemistry's distillation method with MDa, R
2, and SEC of 0.0695, 0.9701, and 0.65, respectively. The study showed that midband FTIR spectroscopy combined with the PLS
regression calibration technique is rapid and accurate for determination of moisture content of CPO samples with a total analysis
time of less than 2 min and less than 2 mL of sample. 相似文献
17.
Alejandro G. Marangoni Dérick Rousseau 《Journal of the American Oil Chemists' Society》1998,75(10):1265-1271
The effects of blending palm oil (PO) with soybean oil (SBO) and lard with canola oil, and subsequent chemical interesterification
(CIE), on their melting and crystallization behavior were investigated. Lard underwent larger CIE-induced changes in triacylglycerol
(TAG) composition than palm oil. Within 30 min to 1 h of CIE, changes in TAG profile appeared complete for both lard and PO.
PO had a solid fat content (SFC) of ∼68% at 0°C, which diminished by ∼30% between 10 and 20°C. Dilution with SBO gradually
lowered the initial SFC. CIE linearized the melting profile of all palm oil-soybean oil (POSBO) blends between 5 and 40°C.
Lard SFC followed an entirely different trend. The melting behavior of lard and lard-canola oil (LCO) blends in the 0–40°C
range was linear. CIE led to more abrupt melting for all LCO blends. Both systems displayed monotectic behavior. CIE increased
the DP of POSBO blends with ≥80% PO in the blend and lowered that of blends with ≤70% PO. All CIE LCO blends had a slightly
lower DP vis-à-vis their noninteresterified counterparts. 相似文献
18.
棕榈油酯交换制备生物柴油的反应动力学 总被引:1,自引:1,他引:0
在甲醇与棕榈油的摩尔比为6∶1和催化剂KOH用量为棕榈油质量1.0%的条件下,研究不同温度下棕榈油制备生物柴油的酯交换反应动力学,采用Origin软件拟合曲线方程,建立棕榈油酯交换反应的宏观动力学模型。研究结果表明:棕榈油制备生物柴油的酯交换反应遵循1.40级动力学方程,反应速率随温度的升高而加快,二者符合Arrhenius方程,该反应的活化能为27.23 kJ/mol,频率因子为1.4×103。文中研究建立的反应动力学模型将对扩大试验研究提供理论依据和基础数据支持。 相似文献
19.
The kinetics of palm oil and mustard oil transesterification are compared. Transesterification of palm oil and mustard oil using KOH as a catalyst was performed at various reaction temperatures ranging from 40 to 60°C. The reaction steps are reversible and transesterification is favoured at elevated temperatures. The reaction step of triglyceride to diglyceride is the rate determining step (RDS) that controls kinetics of overall transesterification with activation energies of 30.2 and 26.8 kJ/mol for palm oil and mustard oil transesterification, respectively. It is found that percentage of saturated compounds play a vital role on transesterification kinetics. © 2011 Canadian Society for Chemical Engineering 相似文献
20.
The color of refined palm oil and palm oil products is conventionally measured using the manually operated Lovibond® Tintometer. In the present study, one manual/visual and three automatic colorimeters for the measurement of vegetable oil color were used for color measurements of refined palm oil. All colorimeters used were commercially available instruments except for an automatic palm oil colorimeter developed specifically for the measurement of palm oil color. The color values obtained from all four instruments were compared using the visually obtained readings as reference values. Results showed that all three automatic instruments gave correlation coefficients of greater than 0.9300 for red color measurements. In addition, the Student t-test showed no difference between the analysis of red color using the visual method and the palm oil colorimeter. This investigation concludes that, although it is extremely difficult to reduce the lack of precision in color measurement of palm oil, a properly designed and calibrated automatic instrument may still be the better choice because reproducibility and repeatability are required in all standard test methods. The palm oil colorimeter offers a ready and relatively inexpensive solution to the problem of color matches based on visual observations. 相似文献