Physical and textural characteristics of hydrogenated low-erucic acid rapeseed oil and low-erucic acid rapeseed oil blends

Low-erucic acid rapeseed oil (LERO) and hydrogenated low-erucic acid rapeseed oil (HLERO) were blended in binary systems. The blends were then studied for their physical properties such as solid fat content, melting curves by DSC, textural properties, and polymorphism. Phase behavior diagrams were constructed from the DSC and X-ray results, and isosolid diagrams were constructed from the NMR results. The mixture of HLERO and LERO displayed a monotectic behavior for all the storage time at 15°C. The aim of this work was to evaluate physical characteristics of binary blends of HLERO and nonydrogenated LERO in order to use only LERO and hardened LERO in bakery shortenings. The mixture of 60% HLERO and 40% LERO is suitable to use as a plastic shortening. This blend is β tending upon storage at 15°C. It could be used in pie crust applications.     

Blending of hydrogenated low-erucic acid rapeseed oil,low-erucic acid rapeseed oil,and hydrogenated palm oil or palm oil in the preparation of shortenings

Two ternary systems of fats were studied. In the first system, low-erucic acid rapeseed oil (LERO), hydrogenated lowerucic acid rapeseed oil (HLERO), and palm oil (PO) were blended. In the second system, hydrogenated palm oil (HPO) was used instead of PO and was blended with LERO and HLERO. The blends were then studied for their physical properties such as solid fat content (SFC), melting curves by DSC, and polymorphism (X-ray). HPO showed the highest melting enthalpy after 48 h at 15°C (141±1 J/g), followed by HLERO (131±2 J/g), PO (110±2 J/g), and LERO (65±4 J/g). Binary phase behavior diagrams were constructed from the DSC and X-ray results. Iso-line diagrams of partial-melting enthalpies were constructed from the DSC results, and binary and ternary isosolid diagrams were constructed from the NMR results. The isosolid diagrams demonstrated formation of a eutectic along the binary blend of PO/HLERO. However, no eutectic effect was observed along the binary lines of HPO/HLERO, PO/LERO, HPO/LERO, or HLERO/LERO. The same results were found with the iso-line diagrams of partial-melting enthalpies. As expected, addition of PO or HPO increased polymorphic stability in the β′ form of the HLERO/LERO mixture.     

TAG composition and solid fat content of palm oil, sunflower oil, and palm kernel olein belends before and after chemical interesterification

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.     

A kinetic study on isothermal crystallization of palm oil by solid fat content measurements

Isothermal crystallization of plam oil was studied by means of differential scanning calorimetry (DSC) as well as by nuclear magnetic resonance spectrometry to monitor its solid fat content (SFC). The temperature of crystallization (Tc) varied from 0 to 30°C, depending on the method used. The plot of %SFC vs. time at 25°C was sigmoidal in shape. However, at lower temperatures, two consecutive curves were clearly visible. Results from DSC experiments showed the following interesting features. At each Tc, the crystals produced were of different compositions. From 0 to 8°C, the thermogram showed three peaks, with the first two peaks (I and II) sharp, and the third (III) rather broad. At elevated temperatures up to 20°C, peak II disappeared totally while peak III tended to shift toward peak I. Above 20°C, both peaks shifted downward to longer times. Peak I continued to be broadened, and then suddenly disappeared at Tc above 24°C. The melting thermograms of the crystals obtained above and below this cut-off point were distinctly different. Kinetic studies on isothermal crystallization based on the data of SFC measurements showed that the data fit well into the Avrami-Erofeev equation with n=3 over the first 70% of the crystallization.     

Isothermal crystallization of hydrogenated sunflower oil: II. growth and solid fat content

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).     

Effect of chemical interesterification on triacylglycerol and solid fat contents of palm stearin,sunflower oil and palm kernel olein blends

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.     

Phase behavior of ternary blends containing dimethylpolycarbonate,tetramethylpolycarbonate and poly[styrene‐co‐(methyl methacrylate)] copolymers (or polystyrene)

The miscibility and phase behavior of ternary blends containing dimethylpolycarbonate (DMPC), tetramethylpolycarbonate (TMPC) and poly[styrene‐co‐(methyl methacrylate)] copolymer (SMMA) have been explored. Ternary blends containing polystyrene (PS) instead of SMMA were also examined. Blends of DMPC with SMMA copolymers (or PS) did not form miscible blends regardless of methyl methacrylate (MMA) content in copolymers. However, DMPC blends with SMMA (or PS) blends become miscible by adding TMPC. The miscible region of ternary blends is compared with the previously determined miscibility region of binary blends having the same chemical components and compositions. The region where the ternary blends are miscible is much narrower than that of binary blends. Based on lattice fluid theory, the observed phase behavior of ternary blends was analyzed. Even though the term representing the Gibbs free energy change of mixing for certain ternary blends had a negative value, blends were immiscible. It was revealed that a negative value of the Gibbs free energy change of mixing was not a sufficient condition for miscible ternary blends because of the asymmetry in the binary interactions involved in ternary blends. Copyright © 2004 Society of Chemical Industry     

Effect of dehydrochlorination of PVC on miscibility and phase separation of binary and ternary blends of poly(vinyl chloride), poly(ethylene-co-vinyl acetate) and poly(styrene-co-acrylonitrile)

The enhancement of miscibility at the lower critical solution temperature (LCST) of the blends poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) (PVC/EVA), poly(vinyl chloride)/poly(styrene-co-acrylonitrile) (PVC/SAN) and poly(vinyl chloride)/poly(ethylene-co-vinyl acetate)/poly(styrene-co-acrylonitrile) (PVC/EVA/SAN) was observed at the micron level. Such miscibility is attributed to the dehydrochlorination and formation of hydrogen bonds between blend components. However, macrolevel immiscibility of these blends heated to the LCST was observed. Such microdomain compatibility of these blends gives a synergistic character. Brittle-type failure observed for LCST samples testifies to the synergism in treated blends. ©1997 SCI     

Attenuation of ultrasonic waves: Influence of microstructure and solid fat content

Ultrasonic technology can be used to monitor the crystallization of fats and determine solid fat content (SFC) online. Ultrasonic waves are attenuated as crystals form and grow, and this attenuation occurs first at higher frequencies. The attenuation of the ultrasonic signal does not depend on the induction times of crystallization of the systems, or on their thermal behavior; but it does depend on SFC and on microstructure, particularly on the crystal size. At low SFC values (≈5%), bigger crystals generate more attenuation. At intermediate SFC values (≈10%), crystal size does not affect signal attenuation and SFC is the key factor responsible for signal attenuation. At high SFC values (up to 20%), crystal size again seems to be the factor that controls attenuation.     

Miscibility windows in ternary polymer blends of a polyester,polymethacrylate and poly(styrene‐co‐acrylonitrile)

Miscibility, phase diagrams and morphology of poly(ε‐caprolactone) (PCL)/poly(benzyl methacrylate) (PBzMA)/poly(styrene‐co‐acrylonitrile) (SAN) ternary blends were investigated by differential scanning calorimetry (DSC), optical microscopy (OM), and scanning electron microscopy (SEM). The miscibility window of PCL/PBzMA/SAN ternary blends is influenced by the acrylonitrile (AN) content in the SAN copolymers. At ambient temperature, the ternary polymer blend is completely miscible within a closed‐loop miscibility window. DSC showed only one glass transition temperature (T_g) for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends; furthermore, OM and SEM results showed that PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 were homogeneous for any composition of the ternary phase diagram. Hence, it demonstrated that miscibility exists for PCL/PBzMA/SAN‐17 and PCL/PBzMA/SAN‐25 ternary blends, but that the ternary system becomes phase‐separated outside these AN contents. Copyright © 2003 Society of Chemical Industry     

Modelling lipase‐catalysed transesterification of fats containing n‐3 fatty acids monitored by their solid fat content

Transesterification of fat blends rich in n‐3 polyunsaturated fatty acids (n‐3 PUFA), catalysed by a commercial immobilised thermostable lipase from Thermomyces lanuginosa, was carried out batch‐wise. Experiments were performed, following central composite rotatable designs (CCRDs) as a function of reaction time, temperature and media formulation. Mixtures of palm stearin, palm kernel oil and a commercial concentrate of triacylglycerols rich in n‐3 PUFA (“EPAX 2050TG” in CCRD‐1 and “EPAX 4510TG” in CCRD‐2) were used. The time‐course of transesterification was indirectly followed by the solid fat content (SFC) values of the blend at 10 °C, 20 °C, 30 °C and 35 °C. A decrease in all SFC values of the blends at 10 °C, 20 °C, 30 °C and 35°C was observed upon transesterification. The SFC_{10 °C} and SFC_{20 °C} of transesterified blends varied between 18 and 48 and SFC_{35 °C} between 6 and 24. These values fulfil the technological requirements for the production of margarines. Under our conditions, lipid oxidation may be neglected. However, the accumulation up to 8.3% free fatty acids in reaction media is a problem to overcome. The development of response surface models, describing both the final SFC value and the SFC decrease, will allow predicting results for novel proportions of fats and oils and/or a novel combination time‐temperature.     

Morphology and supermolecular structure of polypropylene–poly(1-butene)–hydrogenated oligo(cyclopentadiene) ternary blends

Ternary blends containing polypropylene, poly(1-butene), and hydrogenated oligo(cyclopentadiene) have been studied using microscopic, calorimetric, and X-ray diffraction techniques. While no phase separation was found to occur in the melt for all the considered compositions, demixing phenomena were observed by scanning electron microscopy in the ternary blends after crystallization of both polyolefins. On the other hand, a homogeneous surface without the presence of separate domains was observed for blends quenched avoiding the crystallization of polypropylene. The composition has been found to affect the crystallization and the melting properties of the ternary blends and the crystal modification of polypropylene. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1878–1882, 1998     

Enzymatic transesterification of triolein and stearic acid and solid fat content of their products

Two systems were investigated and compared as models for making margarine-type fats. Two immobilized lipases, IM60 from Rhizomucor miehei and SP435 from Candida antarctica, were used to catalyze the transesterification of triolein with stearic acid and stearic acid methyl ester, respectively, in n-hexane. The optimal reaction temperature for both enzymes was 55°C at a mole ratio of triolein to acyl donor of 1:2. Equilibria were reached at 18 h for IM60 and 24 h for SP435. Analysis of the overall yield and incorporation of fatty acid at the sn-2 position indicated that the triacylglycerol products contained 38.4 and 16.2% 18:0 for acidolysis and 34.2 and 11.3% for interesterification reactions, respectively, at the 2-position. With SP435, the softest fat was produced after 18 h of incubation, and the hardest after 30 h. For IM60 system, 18 h of incubation gave the most plastic fat.     

<Emphasis Type="Italic">In situ</Emphasis> monitoring of solid fat content by means of pulsed nuclear magnetic resonance spectrometry and ultrasonics

An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships were found between ultrasonic parameters [integrated response, time of flight (TF), and full width half maximum] and SFC. TF, which is an indirect measurement of the ultrasonic velocity (v), was highly correlated to SFC (r ²>0.9) in a linear fashion (v=2.601 SFC+1433.0).     

Elongational rheology of biodegradable poly(lactic acid)/poly[(butylene succinate)‐co‐adipate] binary blends and poly(lactic acid)/poly[(butylene succinate)‐co‐adipate]/clay ternary nanocomposites

A series of blends based on poly(lactic acid) (PLA) and poly[(butylene succinate)‐co‐adipate] (PBSA) as well as their nanocomposites with nanoclay (PLA/PBSA/Clay ternary nanocomposites) were prepared using the twin‐screw extruder. The blends were prepared for PBSA contents ranging from 25 to 75 wt % and their corresponding nanocomposites were prepared at a single‐clay concentration. The morphology and structure of the blends and the nanocomposites were examined using field emission scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction. Rheological properties (dynamic oscillatory shear measurements and elongational viscosities) of the blends, nanocomposites, and pure components were studied in detail. The strain hardening intensity of different blends and nanocomposites was compared with the behavior of the pure components. Strong strain hardening behavior was observed for blends composed of 50 wt % and higher PBSA content. However, the effect of PBSA content on the elongational viscosity was less pronounced in PLA/PBSA/Clay ternary nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A miscibility study of ternary blends of polystyrene,tetramethylbisphenol-A polycarbonate,and poly(2,6-dimethyl-1,4-phenylene oxide)

Phase behaviorof ternary blends of polystyrene (PS), tetramethylbisphenol-A polycarbonate (TMPC), and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) at two different temperatures (i.e., 210 and 300 °C, respectively) was studied by means of differential scanning calorimetry. Miscibility of the ternary blends at either temperature was found restricted to limited compositions, in agreement with simulated spinodal curves based on published values of interaction parameters. The limited ability of PS, which is separately miscible with TMPC and PPO at 210 °C, to act as a common solvent for the immiscible TMPC/PPO pair at this temperature was explained in terms of the disparity in PS/TMPC and PS/PPO pair interactions (i.e., the 'X effect).     

Novel method to prepare charged mosaic membrane by using dipole‐like microspheres. I. Preparation and characterization of poly(4‐vinylpyridine/n‐butyl acrylate) seed latex with high solid content by soap‐free emulsion polymerization

The stable latex of poly(4‐vinylpyridine‐co‐n‐butyl acrylate) (P4VP/nBA) with a solid content as high as 10 wt % was prepared by a modified soap‐free emulsion polymerization. A mixture of water and organic solvents was employed as the continuous phase for increasing the solid content of the latex. Several organic solvents were investigated and, among them, ethyl acetate (EA) and diethyl ether (DE) were effective. The stable latex with 10 wt % solid content was prepared by charging 10 wt % EA or a EA/DE mixture (5 wt % each); however, more than 10 wt % solid content of the stable latex could not be obtained even by charging more than 10 wt % EA or a EA/DE mixture. The stable latex with 10 wt % solid content, which was crosslinked with less than 0.5 wt % (based on monomer) of ethylene glycol dimethacrylate, was prepared by charging 10 wt % of EA. In this case, however, the pH of the continuous phase had to be adjusted to lower than 4. The effects of EA on the characteristics of the resulting uncrosslinked latex were investigated by employing ζ‐potential measurements and scanning electron microscopy. It was found that the mass of coagulum decreased as the EA increased. At 8 wt % of EA, a stable latex of 10 wt % solid content without any coagulum was obtained. The ζ potential of particles increased from −100 up to 45.7 mV as the EA increased from 0 to 10 wt %. The effects of batch and semicontinuous copolymerization on the morphology of the microspheres were investigated by using DSC and ultrathin cross‐sectional transmission electron miscroscopy photos. A core–shell structure was not found, despite the batch copolymerization of 4VP(1)/nBA(2) (r₁ = 4.3, r₂ = 0.23), even with disparate reactivity ratios. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1731–1740, 2000