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1.
P. Z. Swe Y. B. Che Man H. M. Ghazali L. S. Wei 《Journal of the American Oil Chemists' Society》1994,71(10):1141-1144
Clouding was obtained by storing palm olein at 12.5°C for up to 24h and was separated by centrifugation. the fat crystals
were collected after washing with cold acetone. The crystals were identified according to their fatty acid and triglyceride
composition, carbon number and degree of unsaturation. Palmitic-oleic-palmitic (POP) and palmitic-oleic-stearic (POS) levels
were high in the cloud material, especially in that recovered between 15–18 h of storage. The increase in POP and POS concentrations
was concomitant with a decrease in the content of palmiticoleic-oleic (POO). The least amount of POO was also obtained in
clouds collected between 15–18 h of storage, compared to the original oil sample. The increase of palmitic acid explained
that triglycerides conjugated with palmitic acid molecules in their acyl chains could have been crystallized, and crystallization
could have taken place in the order of the number of palmitic molecule in the acyl chain. The concentrations of the other
triglycerides did not change much throughout the storage period. Further storage caused the composition of the cloud to become
similar to that of the original oil sample. 相似文献
2.
A model margarine was stored under a temperature fluctuation cycle of 5—20 °C until granular crystals were observed. Using information obtained from the granular crystals, the crystallization behaviors of major triacylglycerols of palm oil, 1,3‐dipalmitoyl‐2‐oleoyl‐glycerol (POP), 1‐palmitoyl‐2,3‐dioleoyl‐glycerol (POO), and their mixtures were then investigated. It was shown that in the model margarine, the POP content in the granular crystals was higher than in their surrounding materials, and the X‐ray diffraction pattern of the granular crystals revealed that they were the most stable polymorph, β. 99% pure POP, POO, and their mixtures were then stored under the above‐mentioned temperature cycle. POP was found to form the unstable polymorph, α, when cooled rapidly from the melt. Within 24 hours transformation into the γ polymorph and then into the β polymorph was observed. POO was shown to transform into the β' polymorph from α. When POP and POO were mixed, the β polymorph did not emerge, instead it was shown that POP and POO were both agglomerated in the mixtures, giving rise to the formation of granular crystals. 相似文献
3.
Solvent-free lipase-catalyzed incorporation of stearic acid in palm olein by the 1,3-regiospecific Novo Lipase Lipozyme IM20
resulted in the formation of a complex mixture of fatty acid glycerides and free fatty acids. The stearoyl incorporation in
palm olein gave rise to the formation of 39.3% of the desired cocoa butter-like triglycerides in the fatty acid glyceride
portion, namely distearoyl-oleoyl-glycerol (SOS), palmitoyl-oleoyl-stearoyl-glycerol (POS) and dipalmitoyl-oleoyl-glycerol
(POP). A combination of fractionation steps involving initially the removal of free fatty acids (FFA) from the product mixture
by steam distillation under vacuum, followed by fractional crystallization of the fatty acid-free glycerides in hexane and/or
acetone, gave a fat, whose triglyceride composition and melting profile were comparable to that of cocoa butter as adduced
by reversed-phase high performance liquid chromatography (HPLC) and differential scanning calorimetry (DSC). The yield of
the cocoa butter-like fat was approximately 25% of the weight of the original palm olein. 相似文献
4.
As are traditional fractionation technologies, static dry fractionation is a highly reliable technology for the consistent
production of good-quality palm kernel stearin (PKS) for use as cocoa butter substitute (CBS) after total hydrogenation. A
new process route now permits the production of unhardened yet high-quality CBS. Also an increase in total stearin yield can
be achieved, via a successful refractionation of palm kernel olein. DSC analysis together with pilot static fractionation trials on the palm
kernel olein indicates that a cooling water temperature that is too low (e.g., 17°C) may result in the quick formation of
unstable crystals that are possibly later converted to a more stable form. The resulting mixture of crystals with a possibly
different polymorphic structure is easily squeezed through the filter cloth during filtration, whereas a slower, but more
homogeneous co-crystallization occurs at higher temperature (18°C or higher) and results in a much more stress-resistant slurry.
Polarized light microscopy analysis confirmed that crystal size is not the only determining factor for a successful filtration.
The total two-stage static fractionation of palm kernel oil (PKO) [iodine value (IV) 18] on a pilot scale results in the following
three end products: PKS IV 5 (yield: 29%, for direct use as CBS), PK olein IV 27 (yield: 58%), and PKS IV 7 (yield: 13% for
use as CBS after full hydrogenation). The unhardened PKS IV 5 has outstanding melting and crystallization properties, comparable
to traditional hydrogenated stearin fractions. Therefore, rather than the higher stearin yield, the reduced hydrogenation
capacity is most probably the most important benefit of the two-stage static fractionation process. 相似文献
5.
Shi-Cheng Tong Yee-Ying Lee Teck-Kim Tang Eng-Seng Chan Eng-Tong Phuah 《Journal of the American Oil Chemists' Society》2023,100(11):889-899
Crude palm oil (CPO) is highly abundant in carotenoids. Previous findings found that dry fractionation can concentrate carotenoids from CPO but resulted in a significant loss of carotenoids. Therefore, the present study aimed to utilize solvent fractionation, which offers a better separation efficiency, to concentrate carotenoids from CPO with improved recovery. Computational study revealed a high binding affinity of phytonutrient towards unsaturated triacylglycerols (TAGs) species in olein fraction due to similar polarity. This prediction was further verified with evidence showing strong, positive correlation between the iodine value and carotenoids concentrations of fractionated oil. The difference in binding affinity of saturated and unsaturated TAG towards different solvents can be used as a guide for screening and selection of solvent suitable for recovery of phytonutrient during solvent fractionation. Subsequently, a lab-scale single- stage fractionation study disclosed that crystallization temperature of 15°C, oil to acetone ratio of 1:5 (w/v) for 4 h under agitation at 100 rpm produced olein with the highest carotenoid concentration (637 ppm) and recovery (94%). Subsequent double-stage fractionation successfully concentrated the carotenoids up to 125% with a recovery of >93%. Conclusively, solvent fractionation provides an effective way to concentrate valuable carotenoids from CPO while minimizing the lost. 相似文献
6.
A. Watanabe I. Tashima N. Matsuzaki J. Kurashige K. Sato 《Journal of the American Oil Chemists' Society》1992,69(11):1077-1080
The use of palm oil for plastic fats has encountered serious difficulty due to its crystallization properties, one of which
is the formation of granular crystals. The granular crystals cause sandy teste and inhomogeneity of fat crystal morphology
of end products. In the present study, we analyzed the formation process of these granular crystals. Chemical and physical
analyses for triacylglycerol (TAG) compositions, polymorphism and melting points of the granular crystals led to the conclusion
that the granular crystals are of the most stable polymorph, β1, of POP (1,3-dipalmitoyl 2-oleoyl glycerol) with triple chainlength fat blend consisting of POP and reapeseed oil. The following
characteristics of β1 polymorph of POP contribute to the formation of granular crystals in fat blends containing palm oil: (i) β1 reveals well-defined plate-like crystal morphology, which grows easily into the bulky granular from; (ii) the triple chainlength
structure of POP has a tendency to segregate and does not from a solid solution together with other TAGs. 相似文献
7.
1,3-Dipalmitoyl-2-oleoyl-sn-glycerol (POP) and 1,2-dioleoyl-3-palmitoyl-rac-glycerol (OOP) are two major molecular species that account for roughly half of the total triacylglycerols in palm oil. The
binary phase behavior of a POP/OOP mixture plays an important role in the crystallization of palm oil. We conducted thermodynamic
and kinetic studies of OOP and its mixtures with POP using differential scanning calorimetry and X-ray diffraction with a
conventional generator and synchrotron radiation. We found that OOP has two polymorphs, α as a metastable form and β′ as the
most stable form, and that the two forms are stacked in a triple-chain-length structure. The POP/OOP mixtures exhibited immiscible
eutectic natures in both their metastable and their most stable states, in contrast to POP/1,2-dipalmitoyl-3-oleoyl-rac-glycerol and POP/1,3-dioleoyl-2-palmitoyl-sn-glycerol mixtures, in which molecular compounds of a double-chain-length structure were formed. A time-resolved synchrotron
radiation X-ray diffraction study undertaken during the cooling and heating processes indicated that the α and β′ forms of
the POP and OOP fractions crystallized and melted in separate manners, and that crystallization of the β′ form and the polymorphic
transformation from α to β′ of POP and OOP are promoted in the presence of another component. The absence of molecular compound
crystals in the binary mixtures of POP/OOP is explained by taking into account the molecular interactions of acyl chain packing,
glycerol conformation, and methyl end stacking, among which glycerol conformation appeared to be most influential. 相似文献
8.
The induction times for the crystallization, under isothermal conditions, of refined, bleached, and deodorized palm oil from
the melt were studied by viscometry. At temperatures below 295 K, the crystallization of palm oil was observed to occur in
a two-stage process. This two-stage process was caused by the fractionation of palm oil, most probably into the stearin and
olein fractions. At temperatures higher than 295 K, only a single-stage crystallization process was observed. As seen under
polarized light microscopy, spherical crystals were initially formed from the first fraction at temperatures from 287 to 293
K. The diameters of these spherical crystals decreased as the temperature increased. After that, needle-shaped crystals were
formed from the second fraction and continued to grow from the surface of these spherical crystals until the spherical crystals
were fully enclosed, i.e., the cocrystallization of two polymorphs was observed. At temperatures higher than 293 K, the needle-shaped
crystals formed from a mixture of the two fractions were found to be the only polymorphs developed with the onset of crystallization.
X-ray diffraction results showed that for temperatures below 295 K, the spherical crystals formed from the first fraction
were in α form, whereas the needle-like crystals that nucleated later from the second fraction were in β′ form. β′ crystals
were the only polymorphs formed for temperatures above 295 K. The results obtained were in good agreement with the discontinuity
observed in the induction time vs. temperature curve. Activation free energies for nucleation were calculated according to
the Fisher-Turnbull equation for the various polymorphic forms. Viscometry was observed to be a sensitive method for characterizing
the overall crystallization process. This technique is suitable for induction time studies of palm oil crystallization, especially
at lower temperatures and with viscous oil. 相似文献
9.
Cunhong Chen Hong Zhang Yanlan Bi Lingzhi Cheong 《Journal of the American Oil Chemists' Society》2015,92(2):277-286
The effects of sucrose esters (SEs) with different acyl chain lengths, namely, lauryl (L‐195), palmitoyl (P‐170), stearoyl (S‐170), oleoyl (O‐170), and erucyl (ER‐190), on isothermal crystallization of a palm oil‐based blend (PO–PS) were studied. From this study, it was found that both α‐ and β′‐crystals coexisted following crystallization of PO–PS from melt to room temperature. Addition of SEs P‐170 and S‐170, which had saturated acyl chains similar to PO–PS, resulted in an accelerating crystallization rate, promoting the appearance of α‐crystals and transition to β′‐crystals and increasing viscosity of PO–PS blend. SE O‐170, which is liquid at room temperature, had little effect on blend crystallization. SEs L‐195 and ER‐190, with an acyl chain dissimilar to PO–PS, inhibited triacylglycerol bonding or further integration to the surface of crystals and reduced the crystallization rate and viscosity of the PO–PS blend. The PO–PS blend with SE L‐195 and ER‐190 contained large crystals and resulted in slower formation of α‐crystals and transformation to β′‐crystals. Results from this study indicate that crystallization of PO–PS was greatly influenced by acyl–acyl interactions between acyl chains of SEs and triacylglycerols. 相似文献
10.
Yuichi Shimomura Miki Tsuchiya Satoru Ueno Makoto Shiota 《Journal of the American Oil Chemists' Society》2019,96(1):35-42
The effect of triacylglycerol (TAG) compositions and physical properties related to solid fat content (SFC) on the behavior of granular crystal formation was investigated. Four fat blends involving different 1,3-dipalmitoyl-2-oleoyl-sn-glycerol (POP) and 1-palmitoyl-2,3-dioleoyl-sn-glycerol (POO) compositions or SFC were prepared, and crystallization was investigated using polarizing microscopy, X-ray diffraction, SFC, whereas hardness was determined using a texture analyzer. Samples containing a higher saturated fatty-acid content from palm and higher SFC showed higher β-type crystals in the initial period, yielding a number of small-sized crystals, with no growth occurring afterward. Growth of the granular crystals as a function of time was observed in the samples, transforming from the β’- to β-type polymorph gradually. Large granular crystals at the initial stage were observed in the sample with a higher POO content and lowest SFC. These results suggested that POO promotes the rate of the crystals’ polymorphic transformation, resulting in the growth of granular crystals. In contrast, excess high-melting-point TAG content, such as tripalmitin and POP, retarded granular crystal growth regardless of the increased β’ to β transition rate. We concluded that the behavior of the growth of granular crystals is influenced by the combined effect of TAG composition and SFC. 相似文献
11.
I. NorAini H. Hanirah W. L. Siew M. S. A. Yusoff 《Journal of the American Oil Chemists' Society》1998,75(6):749-751
Cold stability of crude and refined red palm oleins was investigated. Single- and double-fractionated crude as well as refined
single- and double-fractionated red palm oleins were stable against crystallization for more than 1 h but less than 2 h, whereas
commercial red palm oleins remained stable for more than 5 h at 5°C. At 20°C, refined red palm oleins had better resistance
to crystallization than crude palm oleins. Red palm oleins with lower amounts of saturated fatty acids (C16:0 and C18:0), lower levels of POP and POS triacylglycerols, and lower cloud points have increased resistance to crystallization and result
in better cold stability. 相似文献
12.
K. Kawamura 《Journal of the American Oil Chemists' Society》1979,56(8):753-758
Polymorphic behavior of palm oil crystals was studied by DSC isothermal analysis and microscopic observation. Different crystal
forms developed specific spherulites depending on the degree of super-cooling from the melt. The A-form crystal was capable
of forming a dotted spherulite and the B-form crystal of forming a dendritic spherulite. Experimental results of B form crystallization
studied by the DSC and a microscope under kinetic conditions were evaluated using Avarami’s theory, since the behavior of
the oil during crystallization related well to that of high polymers. The crystallization process was divided into nucleation
and crystal-growth phases to facilitate a theoretical treatment similar to that of high polymers, providing crystals possessing
overall structural regularity. 相似文献
13.
分别采用低黏度和高黏度的聚对苯二甲酸乙二醇酯(PET)树脂切片,利用差示扫描量热分析(DSC)的方法研究不同的熔融温度条件对PET结晶行为和熔融行为的影响。结果表明:和高黏度PET相比,低黏度PET的结晶过程对熔融温度的变化极其敏感,不同熔融温度将对它的结晶行为与熔融行为产生显著的影响;在同等条件下,低黏度PET结晶速率快且易生成稳定的结晶结构,其稳定结晶的熔融温度要比高黏度PET高数度;总体上,采用较低的熔融温度有利于提高PET结晶温度和结晶速率,而采用较高的熔融温度有利于提高PET结晶的稳定性。 相似文献
14.
Nor Aini Idris Leny deMan T. S. Tang C. L. Chong 《Journal of the American Oil Chemists' Society》1996,73(8):995-1001
Seven samples of domestic and imported Malaysian tub margarines were analyzed for their fatty acid and triglyceride (carbon
number) composition, solid fat content, dropping and softening points, crystallization temperature, polymorphic form, color,
and textural attributes. Domestic margarines were formulated from palm oil or palm olein and palm kernel oil with a liquid
oil but no hydrogenated oils. Two imported products contained hydrogenated palm oil product, which resulted in a high level
of β′ crystals, whereas the domestic nonhydrogenated products contained more β than β′ crystals. Crystal habit was related
to the fatty acid and triglyceride composition of the high-melting glycerides. Domestic products were firmer in texture, probably
because they were formulated to be sold in a tropical climate. 相似文献
15.
Marisol Cordova-Barragan Alejandro G. Marangoni Fernanda Peyronel Elena Dibildox-Alvarado 《Journal of the American Oil Chemists' Society》2021,98(4):413-424
A high behenic stabilizer (HBS) at concentrations of 0.3%, 0.6%, and 0.9% w/w was added to the oil phase of a fat-reduced water-in-oil (W/O) emulsion intended for margarine manufacture. The crystallization kinetics, thermal behavior, and microstructure of an oil phase and its 35/65 w/w fat-reduced W/O emulsion were studied. The oil phase was composed of a palm oil-based model fat blend, three emulsifiers, and the HBS. Differential scanning calorimetry results showed that, when 0.9% of stabilizer was added, the crystallization started 2.5 °C higher than when no HBS was added, hence reducing the time needed for crystallization. Polarized light microscopy results showed that the cocrystallization of the high-melting triacylglycerols of the oil phase with the HBS significantly decreased the fat crystal size and increased the number of crystals. The solid fat content also was increased by 2.4%. Interfacial tension experiments corroborated that HBS was located in the oil phase and not at the emulsion interface. This work shows that margarine can be successfully manufactured by adding 0.9% HBS to a 35/65 w/w fat-reduced W/O emulsion without losing functionality, as shown by the presence of the β′ polymorph. This work also suggests that 15% fat could be removed from the system without changing functionality by merely adding up to 0.9% of HBS. 相似文献
16.
Y. B. Che Man T. Haryati H. M. Ghazali B. A. Asbi 《Journal of the American Oil Chemists' Society》1999,76(2):237-242
Gas-liquid chromatography and high-performance liquid chromatography (HPLC) were used to determine fatty acids and triglyceride
(TG) compositions of crude palm oil (CPO), refined, bleached, and deodorized (RBD) palm oil, RBD palm olein, and RBD palm
stearin, while their thermal profiles were analyzed by differential scanning calorimeter (DSC). The HPLC chromatograms showed
that the TG composition of CPO and RBD palm oil were quite similar. The results showed that CPO, RBD palm oil, RBD olein,
and superolein consist mainly of monosaturated and disaturated TG while RBD palm stearin consists mainly of disaturated and
trisaturated TG. In DSC cooling thermograms the peaks of triunsaturated, monosaturated and disaturated TG were found at the
range of −48.62 to −60.36, −25.89 to −29.19, and −11.22 to −1.69°C, respectively, while trisaturated TG were found between
13.72 and 27.64°C. The heating thermograms of CPO indicated the presence of polymorphs β2′, α, β2′, and β1. The peak of CPO was found at 4.78°C. However, after refining, the peak shifted to 6.25°C and became smaller but more apparent
as indicated by RBD palm oil thermograms. The heating and cooling thermograms of the RBD palm stearin were characterized by
a sharp, high-melting point (high-T) peak temperature and a short and wide low-melting point (low-T) peak temperature, indicating
the presence of occluded olein. However, for RBD palm olein, there was only an exothermic low-T peak temperature. The DSC
thermograms expressed the thermal behavior of various palm oil and its products quite well, and the profiles can be used as
guidelines for fractionation of CPO or RBD palm oil. 相似文献
17.
K Dzulkefly W
H Lim S Hamdan K Norsilah 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(6):627-632
Solubilization of methanol and ethanol in crude palm oil, refined, bleached and deodorized palm oil (RBD PO) and RBD palm olein (POL) was studied using medium‐ and long‐chain alkanols (C4–C12). Ternary phase diagrams were constructed to determine the solubilization (isotropic) region. The results showed that methanol and ethanol are solubilized to a greater extent in an unsaturated palm olein than the saturated CPO and RBD PO in the presence of long‐chain alkanols. The minima of the solubilization curves for dodecanol, decanol and octanol were 27%, 30% and 33% of alkanol respectively in the methanol system, whereas in the ethanol system, the minima for the same alkanols were found at 22%, 24% and 27%. The longer chain‐length alkanol (dodecanol) requires a lesser amount (21% and 32%) to achieve miscibility compared with 53% and 57% for butanol in mixtures containing 70:30 and 50:50 wt ratios respectively. The kinematic viscosity of the isotropic solutions increases with the chain‐length and percentage of alkanols. Solubilization using a POL/methanol/butanol system significantly reduced the kinematic viscosity of POL from 72.7 mm2 s?1 to the value allowable for No 2 diesel fuel (1.9–4.1 mm2 s?1) or about a 96% reduction from the initial kinematic viscosity of POL. © 2002 Society of Chemical Industry 相似文献
18.
Mohd Zaki Sulaiman Nik Meriam Sulaiman Sivaruby Kanagaratnam 《Journal of the American Oil Chemists' Society》1997,74(12):1553-1558
This paper discusses the results of an investigation to identify triacylglycerols that induce clouding of refined bleached
deodorized (RBD) palm olein, which occurred within 24 h after fractionation. The experiments were conducted in a jacketed
glass vessel in which the liquid sample was cooled from 70 to 23°C at a predetermined rate. Clouding began at around 28.5°C.
The presence of three different types of saturated triglycerides, namely tripalmitin, dipalmitoyl-myristoylglycerol and dipalmitoyl-stearoyl-rac-glycerol, is critical in the formation of nuclei and thus clouding of the RBD palm olein. This conclusion is based on the
significant increase in the relative concentration of these components in the nuclei as compared to the mother oil. 相似文献
19.
David A. Glassner Eric A. Grulke 《Journal of the American Oil Chemists' Society》1986,63(8):1066-1071
The surfactant concentration, the electrolyte concentration, the detergent solution to tallow weight ratio and the crystal surface area affect the olein yield from the detergent fractionation of tallow. Three crystal sizes were produced by using various rates of cooling for the partial crystallization step. The amount of sodium dodecyl sulfate (SDS) needed to maximize olein yield was proportional to the surface area of the crystals. The olein yield of the separation increased with increasing detergent solution to tallow weight ratio and increased with increasing electrolyte concentration up to their optimum levels. 相似文献
20.
Susumu Miura Akihiro Yamamoto Hiroaki Konishi 《European Journal of Lipid Science and Technology》2002,104(4):222-227
This study has been carried out on solidification of a model cream using palm oil as a sole fat source. It was found that the addition of 1‐palmitoylglycerol to palm oil promoted the solidification of the model cream while the addition of 1‐oleoylglycerol had no such effect. Solid fat content of palm oil in the cream with 1‐palmitoylglycerol was found to be lower than those of palm oil and palm oil with 1‐oleoylglycerol after cooling from 60 to 5 °C. Crystallization behaviors of bulk palm oil and mixture of 1, 3‐dipalmitoyl‐ 2‐oleoyl‐glycerol (POP) and 1‐palmitoyl‐2, 3‐dioleoyl‐glycerol (POO) were then studied in the presence of monoacylglycerols. Formation of granular crystals was observed for palm oil and POP/POO mixture in the presence of 1‐palmitoylglycerol. HPLC of the granular crystals revealed that agglomeration of higher melting point triacylglycerols (TAGs) around 1‐palmitolyglycerol took place, which promoted the formation of granular crystals. It was suggested that the agglomeration of higher melting point TAGs around 1‐palmitoylglycerol which was preferentially adsorbed at the oil‐water interface of oil droplets in the model cream led to destabilization of oil‐in‐water emulsion and the solidification of the model cream. At the same time, it was suggested that the fatty acid moiety of emulsifiers played an important role in the agglomeration of TAGs and stabilization of o/w emulsions. 相似文献