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.     

The influence of chemical interesterification on physicochemical properties of complex fat systems 1. Melting and crystallization

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.     

<Emphasis Type="Italic">Trans</Emphasis>-Free Plastic Shortenings Prepared with Palm Stearin and Rice Bran Oil Structured Lipid

Rice bran oil structured lipid (RBOSL) was produced from rice bran oil (RBO) and the medium chain fatty acid (MCFA), caprylic acid, with Lipozyme RM IM as biocatalyst. RBOSL and RBO were mixed with palm stearin (PS) in ratios of 30:70, 40:60, 50:50, 60:40 and 70:30 v/v (RBOSL to PS) to formulate trans-free shortenings. Fatty acid profiles, solid fat content (SFC), melting and crystallization curves and crystal morphology were determined. The content of caprylic acid in shortening blends with RBOSL ranged from 9.92 to 22.14 mol%. Shortening blends containing 30:70 and 60:40 RBOSL or RBO and PS had fatty acid profiles similar to a commercial shortening (CS). SFCs for blends were within the desired range for CS of 10–50% at 10–40 °C. Shortening blends containing higher amounts of RBOSL or RBO had melting and crystallization curves similar to CS. All shortening blends contained primarily β′ crystals. RBOSL blended with PS was comparable to RBO in producing shortenings with fatty acid profiles, SFC, melting and crystallization profiles and crystal morphologies that were similar. RBOSL blended with PS can possibly provide healthier alternative to some oils currently blended with PS and commercial shortening to produce trans-free shortening because of the health benefits of the MCFA in RBOSL.     

Melting and Solidification Properties of Palm Kernel Oil,Tallow, and Palm Olein Blends in the Preparation of Shortening

Ternary systems composed of palm kernel oil (PKO), tallow, and palm olein (POo) were studied in terms of their physical properties such as solid fat content (SFC), melting characteristics by DSC and polymorphism by X-ray diffraction. Ternary phase behavior was analyzed with isosolid diagrams. The results showed that as the POo content of the blends was increased the SFC value decreased, while the increase of tallow content increased the SFC value. Eutectic effects within the ternary system were confirmed from the deviation of the measured SFC from the calculated SFC for corresponding thermodynamically ideal blends. The deviation reached a maximum when the amounts of PKO and POo are both about 45%. X-ray diffraction results showed that addition of PKO into the blends promoted stabilization in the β′ crystalline form.     

Phase Equilibrium and Optimization Tools: Application for Enhanced Structured Lipids for Foods

Solid–liquid phase equilibrium modeling of triacylglycerol mixtures is essential for lipids design. Considering the α polymorphism and liquid phase as ideal, the Margules 2-suffix excess Gibbs energy model with predictive binary parameter correlations describes the non ideal β and β′ solid polymorphs. Solving by direct optimization of the Gibbs free energy enables one to predict from a bulk mixture composition the phases composition at a given temperature and thus the SFC curve, the melting profile and the Differential Scanning Calorimetry (DSC) curve that are related to end-user lipid properties. Phase diagram, SFC and DSC curve experimental data are qualitatively and quantitatively well predicted for the binary mixture 1,3-dipalmitoyl-2-oleoyl-sn-glycerol (POP) and 1,2,3-tripalmitoyl-sn-glycerol (PPP), the ternary mixture 1,3-dimyristoyl-2-palmitoyl-sn-glycerol (MPM), 1,2-distearoyl-3-oleoyl-sn-glycerol (SSO) and 1,2,3-trioleoyl-sn-glycerol (OOO), for palm oil and cocoa butter. Then, addition to palm oil of Medium-Long-Medium type structured lipids is evaluated, using caprylic acid as medium chain and long chain fatty acids (EPA-eicosapentaenoic acid, DHA-docosahexaenoic acid, γ-linolenic-octadecatrienoic acid and AA-arachidonic acid), as sn-2 substitutes. EPA, DHA and AA increase the melting range on both the fusion and crystallization side. γ-linolenic shifts the melting range upwards. This predictive tool is useful for the pre-screening of lipids matching desired properties set a priori.     

Phase behavior of a binary lipid shortening system: From molecules to rheology

The phase behavior of fully hydrogenated canola oil in soybean oil was investigated using iso-solid lines from temperature-controlled pulse-NMR along with DSC data, with the rate of cooling of crystallized samples kept constant. The molecular diversity within the fat system was investigated using HPLC and GC. The microstructure of the fats was determined using a temperature-controlled polarized light microscope, and the polymorphism of the solidified fat structures was determined via a temperature-controlled X-ray diffractometer. Hardness was measured by a temperature-controlled Instron mechanical analyzer with a penetration cone. The phase behavior predicted by the DSC and iso-solid lines did not account for the hardness trends observed, as the microstructure and polymorphism of the fat also played a significant role. The addition of hard fat to a system did not consistently increase the hardness of the fat system. Furthermore, the solution behavior demonstrated by the iso-solid line diagram did not account for all trends in melting behavior, as both intersolubility and polymorphic changes occurred simultaneously. it was found that variations in hardness can be inferred from structural changes, although the structural level causing variation differs.     

Physical Properties of <Emphasis Type="Italic">trans</Emphasis>-Free Bakery Shortening Produced by Lipase-Catalyzed Interesterification

Lipase-catalyzed interesterified solid fat was produced with fully hydrogenated soybean oil (FHSBO), and rapeseed oil (RSO) and palm stearin (PS) in a weight ratio of 15:20:65, 15:40:45 and 15:50:35. The interesterified fats contained palmitic (27.8–44.6%), stearic (15.6–16.2%), oleic (27.5–36.5%) and linoleic acids (8.0–13.5%). After interesterification of the blends, the physical properties of the products changed and showed lower melting points and solid fat contents, different melting and crystallization behaviors as well as the formation of more stable crystals. The produced interesterified fats (FHSBO:RSO:PS 15:20:65, 15:40:45 and 15:50:35 blends) contained desirable crystal polymorphism (β′ form) as determined by X-ray diffraction spectroscopy, a long plastic range with solid fat content of 51–63% at 10 °C to 4–12% at 40 °C, and melting points of 39 (15:50:35), 42 (15:50:45) and 45 °C (15:20:65). However, a reduction in tocopherols (α and γ) content and a reduced oxidative stability were observed in the interesterified fats. The physical properties of the interesterifed fats were influenced by the amount of PS, resulting in more hardness and higher solid fat contents for 15:20:65 than 15:40:45 and 15:50:35 blends. The present study suggested that the produced interesterified fats containing trans-free fatty acids could be used as alternatives to hydrogenated types of bakery shortenings.     

Physico-chemical characteristics of palm-based oil blends for the production of reduced fat spreads

The effect of blending and interesterification on the physicochemical characteristics of fat blends containing palm oil products was studied. The characteristics of the palm-based blends were tailored to resemble oil blends extracted from commercial reduced fat spreads (RFS). The commercial products were found to contain up to 20.4% trans fatty acids, whereas the palm-based blends were free of trans fatty acids. Slip melting point of the blends varied from 26.0–32.0°C for tub, and 30.0–33.0°C for block RFS. Solid fat content at 5 and 10°C (refrigeration temperature), respectively, varied from 10.9–19.7% and 8.5–17.6% for tub, and 28.2–38.6% and 20.8–33.5% for block RFS. Melting enthalpy of the tub RFS varied from 35.0–54.3 J/g and that of block RFS varied from 58.0–75.4 J/g. To produce block RFS, 65% palm oil (PO) and 18% palm kernel olein (PKOo) could be added in a ternary blend with sunflower oil (SFO), but only 47% PO and 10% PKOo are suggested for tub RFS. Higher proportion of PO, i.e., 72% for block RFS and 65% for tub RFS, could be used after the ternary blend was interesterified. Although a ternary blend of palm olein (POo)/SFO/PKOo was not suitable for RFS formulation, after interesterification as much as 90% POo and 26% PKOo could be used in the block RFS formulation. For tub RFS a maximum of 30% POo was found suitable.     

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.     

Melting behavior of blends of milk fat with hydrogenated coconut and cottonseed oils

The melting behavior of milk fat, hydrogenated coconut and cottonseed oils, and blends of these oils was examined by nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC). Solid fat profiles showed that the solid fat contents (SFC) of all blends were close to the weighted averages of the oil components at temperatures below 15°C. However, from 15 to 25°C, blends of milk fat with hydrogenated coconut oils exhibited SFC lower than those of the weighted averages of the oil components by up to 10% less solid fat. Also from 25 to 35°C, in blends of milk fat with hydrogenated cottonseed oils, the SFC were lower than the weighted averages of the original fats. DSC measurements gave higher SFC values than those by NMR. DSC analysis showed that the temperatures of crystallization peaks were lower than those of melting peaks for milk fat, hydrogenated coconut oil, and their blends, indicating that there was considerable hysteresis between the melting and cooling curves. The absence of strong eutectic effects in these blends suggested that blends of milk fat with these hydrogenated vegetable oils had compatible polymorphs in their solid phases. This allowed prediction of melting behavior of milk-fat blends with the above oils by simple arithmetic when the SFC of the individual oils and their interaction effects were considered.     

Storage stability evaluation of some packed vegetable oil blends

The physicochemical characteristics and minor component contents of blended oils packed in pouches in relation to starting oils used for blending were studied over a period of 6 mon at two storage temperatures and humidity conditions: 27°C/65% RH and 40°C/30–40% RH. Color, PV, FFA value, β-carotene content, tocopherol content, and oryzanol content of the oils were monitored at regular intervals. The color, PV (0.6–20.7 meq O₂/kg, FFA value (0.08–2.1%), tocopherol content (360–1700 ppm%), oryzanol content (460–2,000 mg%), and sesame oil antioxidants (400–2,000 mg%) were not changed in either the starting oils or their blends. Oils and oil blends containing a higher initial PV (18.9–20.7 meq O₂/kg) showed a slight reduction in value at 40°C, whereas oils having lesser PV of 5–10 showed a slight increase during the storage period. Among the minor components studied, only β-carotene showed a reduction, 8.9–60.2% at 27°C and 48–71% at 40°C, for the different oil blends studied. The observed results indicated that the packed oil blends studied were stable under the conditions of the study, and the minor components, other than β-carotene, remained unaltered in the package even at the end of 6 mon of storage.     

Comparison of ultrasonic and pulsed NMR techniques for determination of solid fat content

In this work an ultrasonic velocity technique was compared to direct pulsed NMR (pNMR) spectroscopy for the determination of the solid fat content (SFC) of anhydrous milk fat (AMF), cocoa butter (CB), and blends of AMF and CB with canola oil (CO) in the range 100 to 70% (w/w). In situ measurements of ultrasonic velocity were carried out during cooling (50–5°C) and heating (5–50°C) of the fat samples, and SFC values were calculated. The SFC were also determined simultaneously by pNMR. Peak melting temperatures determined by DSC were used as an indicator of the polymorphic state of the different fats and fat blends. Estimates of SFC obtained using pNMR and ultrasonic velocimetry did not agree. Our results suggested that ultrasonic velocity was highly dependent on the polymorphic state of the solid fat. Ultrasonic velocity in fat that contained crystals in a more stable polymorphic form was consistently higher than in fat that contained crystals in a less stable polymorphic modification. A high attenuation of the signal was observed in milkfat and CB at lower temperatures, particularly after sitting for 24 h. This high attenuation could be a product of scattering by crystallites or by microscopic air pockets formed upon solidification of the material, or it could be due to high ultrasonic absorption associated with phase transitions. This research highlights some of the problems associated with applying ultrasonics to the determination of SFC.     

Physical properties of Pseudomonas and Rhizomucor miehei lipase-catalyzed transesterified blends of palm stearin:palm kernel olein

The physical properties of Pseudomonas and Rhizomucor miehei lipase-catalyzed transesterified blends of palm stearin:palm kernel olein (PS:PKO), ranging from 40% palm stearin to 80% palm stearin in 10% increments, were analyzed for their slip melting points (SMP), solid fat content (SFC), melting thermograms, and polymorphic forms. The Pseudomonas lipase caused a greater decrease in SMP (15°C) in the PS:PKO (40:60) blend than the R. miehei lipase (10.5°C). Generally, all transesterified blends had lower SMP than their unreacted blends. Pseudomonas lipase-catalyzed blends at 40:60 and 50:50 ratio also showed complete melting at 37°C and 40°C, respectively, whereas for the R. miehei lipase-catalyzed 40:60 blend, a residual SFC of 3.9% was observed at 40°C. Randomization of fatty acids by Pseudomonas lipase also led to a greater decrease in SFC than the rearrangement of fatty acids by R. miehei lipase. Differential scanning calorimetry results confirmed this observation. Pseudomonas lipase also successfully changed the polymorphic forms of the unreacted blends from a predominantly β form to that of an exclusively β′ form. Both β and β′ forms existed in the R. miehei lipase-catalyzed reaction blends, with β′ being the dominant form.     

Poly(vinylidene fluoride)/cellulose acetate-butyrate blends: Characterization by DSC,WAXS, and FTIR

Summary Binary blends of poly(vinylidene fluoride), PVDF, with cellulose acetatebutyrate (CAB) were characterized by using differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS) and Fourier transform infrared spectroscopy (FTIR). This system was proved to be partially miscible, showing a significant decrease on the thermal parameters (ΔH_f and T_m) as well as on the crystallinity index (CI) of PVDF with CAB content on the second DSC run. γ crystalline form of PVDF, which is predominant in the as-cast blends, changed to α form with the first DSC run. In contrast, thermal treatment at 200°C (30 min) on blends containing 40–60 wt. % of CAB caused the γ phase to be predominant, as observed by FTIR.     

Modification of margarine fats by enzymatic interesterification: Evaluation of a solid-fat-content-based exponential model with two groups of oil blends

Lipozyme TL IM-catalyzed interesterification for the modification of margarine fats was carried out in a batch reactor at 70°C with a lipase dosage of 4%. Solid fat content (SFC) was used to monitor the reaction progress. Lipase-catalyzed interesterification, which led to changes in the SFC, was assumed to be a first-order reversible reaction. Accordingly, the change in SFC vs. reaction time was described by an exponential model. The model contained three parameters, each with a particular physical or chemical meaning: (i) the initial SFC (SFC₀), (ii) the change in SFC (ΔSFC) from the initial to the equilibrium state, and (iii) the reaction rate constant value (k). SFC_o and ΔSFC were related to only the types of blends and the blend ratios. The rate constant k was related to lipase activity on a given oil blend. Evaluation of the model was carried out with two groups of oil blends, i.e., palm stearin/coconut oil in weight ratios of 90∶10, 80∶20, and 70∶30, and soybean oil/fully hydrogenated soybean oil in weight ratios of 80∶20, 65∶35, and 50∶50. Correlation coefficients higher than 0.99 between the experimental and predicted values were observed for SFC at temperatures above 30°C. The model is useful for predicting changes in the SFC during lipase-catalyzed interesterification with a selected group of oil blends. It also can be used to control the process when particular SFC values are targeted.     

Interesterification of tallow and sunflower oil

The objective of this study was to manufacture a shortening using chemical interesterification (IT) of tallow-sunflower oil blends to replace fish oil in the present formulation, which is now in short supply in Chile. The significant variables of the IT process were obtained by 2⁴⁻¹ fractional factorial design. The proportion of tallow (T) in the blend, catalyst concentration, and reaction temperature had a significant effect on the melting point (mp) (P≤0.05). IT of tallow and sunflower oil blends (90∶10 and 70∶30) diminished the mp, dropping point, and refractive index compared to tallow. However, a noninteresterified 90∶10 blend mp was not significantly different from tallow. IT produced a solid fat content (SFC) profile of IT90∶10 blend that was appropriate for use in shortenings for the baking industry. Blending and IT of the 90∶10 blend increased the melting profile of the tallow and the melting range from −40 to 60°C while the endotherms of the middle-melting triacylglycerols (TAG) decreased. The IT90∶10 blend hardnesswas 70% lower than tallow hardness, and the crystal network was composed of large spherulites in a network. IT resulted in an appropriate method to improve physical properties of tallow, whereas blending did not significantly modify it. The interesterification changed the SFC profile of IT90∶10, giving a more appropriate shortening for use in the baking industry.     

Effects of superfatting agents on cracking phenomena in toilet soap

Palm stearin (POs) is one of the cheapest sources of C16–C18 fatty acids for use in soap making. Toilet-soap formulations containing a high content of POs, however, would result in hard soaps with a tendency to form cracks on the surface. This phenomenon can be overcome by addition of superfatting agents to increase plasticity of the finished product. In this study, two different blends of soap made from distilled POs, palm oil (PO), and palm kernel oil (PKO) fatty acids in the ratio of 40POs/40PO/20PKO and 70POs/30PKO were evaluated. The soaps were superfatted with glycerin, palm kernel olein, coconut oil, olive oil and canola oil. The levels of incorporation of each superfatting material were 1, 2, 4, and 6%, respectively. The samples were subsequently tested for both wet and dry crackings using the Hewitt Soap Company methods (numbers 78 and 79, respectively). The superfatted soaps had a total fatty matter of 73–83% and an average moisture content of 10%. The penetration value which indicates hardness increased with increasing amount of superfatting agents. Foaming or lathering property was good with the exception of the formulation using palm kernel olein and canola oil as superfatting agents. At all the above levels of superfatting agents added, no cracks were observed during both wet and dry cracking tests. A sample of soap superfatted with 2% canola oil, however, developed cracks during the wet cracking test. This resulted in a test score of 7. Superfatting soaps with 1–2% neutral oils or glycerin resulted in better quality soaps that were free of cracks.     

Restructing butterfat through blending and chemical interesterification. 1. Melting behavior and triacylglycerol modifications

Chemical interesterification of butterfat-canola oil blends, ranging from 100% butterfat to 100% canola oil in 10% increments, decreased solid fat content (SFC) of all blends in a nonlinear fashion in the temperature range of 5 to 40°C except for butterfat and the 90∶10 butterfat/canola oil blend, whose SFC increased between 20 and 40°C. The sharp melting associated with butterfat at 15–20°C disappeared upon interesterification. Heats of fusion for butterfat to the 60∶40 butterfat/canola oil blend decreased from 75 to 60 J/g. Blends with >50% canola oil displayed a much sharper drop in enthalpy. Heats of fusion were 30–50% lower on average for interesterified blends than for their noninteresterified counterparts. Both noninteresterified and interesterified blends deviated substantially from ideal solubility, with greater deviation as the proportion of canola oil increased. The change in the entropy of melting was consistently higher for noninteresterified blends than for interesterified blends. Chemical interesterification generated statistically significant differences for all triacylglycerol carbon species (C) from C₃₀ to C_56′ except for C_42′ and in SFC at most temperatures for all blends.     

Zero-<Emphasis Type="Italic">trans</Emphasis> shortening using palm stearin and rice bran oil

Several pilot-scale trials reported in this paper, using palm stearin-rice bran oil (PS-RBO) blends, obviously did not contain trans FA (TFA), whereas the commercial products were found to contain 18–27% TFA. The effects of processing conditions such as rate of agitation, crystallization temperature, and composition of the blends on the crystal structure of shortenings were studied. The products were evaluated for their physicochemical characteristics using DSC, X-ray diffraction (XRD), HPLC, and FTIR techniques. The formulation containing 50% PS and 50% RBO showed melting and cooling characteristics similar to those of hydrogenated commercial “vanaspati” samples. Analysis of the FA composition revealed that the formulated shortenings contained 15–19% C_18∶2 PUFA. Tocopherol and tocotrienol contents of the experimental shortenings were in the range of 850–1000 ppm with oryzanol content up to 0.6%. XRD studies demonstrated that the crystal form in the shortenings was predominantly the most stable β′ form, and there was less of the undesirable β form.     

The effect of supercooling on crystallization of cocoa butter-vegetable oil blends

The solid fat content (SFC), Avrami index (n), crystallization rate (z), fractal dimension (D), and the pre-exponential term [log(γ)] were determined in blends of cocoa butter (CB) with canola oil or soybean oil crystallized at temperatures (T _Cr) between 9.5 and 13.5°C. The relationship of these parameters with the elasticity (G′) and yield stress (σ^*) values of the crystallized blends was investigated, considering the equilibrium melting temperature (T _M ^o) and the supercooling (i.e., T _Cr ^o−T _M ^o) present in the blends. In general, supercooling was higher in the CB/soybean oil blend [T _M ^o=65.8°C (±3.0°C)] than in the CB/canola oil blend [T _M ^o=33.7°C (±4.9°C)]. Therefore, under similar T _Cr values, higher SFC and z values (P<0.05) were obtained with the CB/soybean oil blend. However, independent of T _Cr TAG followed a spherulitic crystal growth mechanism in both blends. Supercooling calculated with melting temperatures from DSC thermograms explained the SFC and z behavior just within each blend. However, supercooling calculated with T _M ^o explained both the SFC and z behavior within each blend and between the blends. Thus, independent of the blend used, SFC described the behavior of G′_eq and σ^* and pointed out the presence of two supercooling regions. In the lower supercooling region, G′_eq and σ^* decreased as SFC increased between 20 and 23%. In this region, the crystal network structures were formed by a mixture of small β′ crystals and large β crystals. In contrast, in the higher supercooling region (24 to 27% SFC), G′_eq and σ^* had a direct relationship with SFC, and the crystal network structure was formed mainly by small β′ crystals. However, we could not find a particular relationship that described the overall behavior of G′_eq and σ^* as a function of D and independent of the system investigated.