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.     

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.     

Oxidative stability of blends and interesterified blends of soybean oil and palm olein

Improvement of oxidative stability of soybean oil by blending with a more stable oil was investigated. Autoxidation of blends and interesterified blends (9∶1, 8∶2, 7∶3 and 1∶1, w/w) of soybean oil and palm olein was studied with respect to fatty acid composition, fatty acid location and triacylglycerol composition. Rates of formation of triacylglycerol hydroproxides, peroxide value and volatiles were evaluated. The fatty acid composition of soybean oil was changed by blending. Linolenic and linoleic acids decreased and oleic acid increased. The triacylglycerol composition of blends and interesterified blends was different from that of soybean oil. Relative to soybean oil, LnLL, LLL, LLO, LLP, LOO and LLS triacylglycerols were lowered and POO, POP and PLP were higher in blends and interesterified blends (where Ln, L, O, P and S represent linolenic, linoleic, oleic, palmitic and stearic acids, respectively). Interesterification of the blends leads to a decrease in POO and POP and an increase in LOP. Linoleic acid concentration at triacylglycerol carbon-2 was decreased by blending and interesterification. Rates of change for peroxide value and oxidation product formation confirmed the improvement of soybean oil stability by blending and interesterification. But, blends were more stable than interesterified blends. Also, the formation of hexanal, the major volatile of linoleate hydroperoxides of soybean oil, was decreased by blending and interesterification.     

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.     

DSC study on the melting properties of palm oil, sunflower oil, and palm kernel olein blends before and after chemical interesterification

Changes in DSC melting properties of palm oil (PO), sunflower oil (SFO), palm kernel olein (PKOo), and their belends in various ratios were studied by using a combination of blending, and chemical interesterification (CIE) techniques and determining total melting (ΔH _f ) and partial melting (ΔH _i°C ) enthalpies. Blending and CIE significantly modified the DSC melting properties of the PO/SFO/PKOo blends. PO and blends containing substantial amounts of PO and PKOo experienced an increase in their DSC ΔH _f and ΔH _i°C following CIE. The DSC ΔH _f and ΔH _i°C of PKOo, blends of PO/SFO at 1∶1 and 1∶3 ratios, and all blends of PKOo/SFO significantly decreased after CIE. The DSC ΔH _f and ΔH _i°C of SFO changed little following CIE. Randomization of FA distribution within and among TAG molecules of PO and PKOo led to modification in TAG composition of the PO/PKOo blends and improved miscibility between the two fats and consequently diminished the eutectic interaction that occurred between PO and PKOo.     

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.     

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.     

Trans‐free fats through interesterification of canola oil/palm olein or fully hydrogenated soybean oil blends

Binary blends of canola oil (CO) and palm olein (POo) or fully hydrogenated soybean oil (FHSBO) were interesterified using commercial lipase, Lypozyme TL IM, or sodium methoxide. Free fatty acids (FFA) and soap content increased and peroxide value (PV) decreased after enzymatic or chemical interesterification. No difference was observed between the PV of enzymatically and chemically interesterified blends. Enzymatically interesterified fats contained higher FFA and lower soap content than chemically prepared fats. Slip melting point (SMP) and solid‐fat content (SFC) of CO and POo blends increased, whereas those of CO and FHSBO blends decreased after chemical or enzymatic interesterification. Enzymatically interesterified CO and POo blends had lower SMP and SFC (at some temperatures) than chemically interesterified blends. The status was reverse when comparing chemically and enzymatically interesterified CO and FHSBO blends. The induction period for oxidation at 120°C of blends decreased after interesterification. However, chemically interesterified blends were more oxidatively stable than enzymatically interesterified blends. Interesterified blends of CO and POo or FHSBO displayed characteristics suited to application as trans‐free soft tub, stick, roll‐in and baker's margarine, cake shortening and vanaspati fat.     

Chemical and Enzymatic Interesterification of a Blend of Palm Stearin: Soybean Oil for Low trans-Margarine Formulation

A blend of palm stearin and soybean oil (70/30, wt%) was modified by chemical interesterification (CIE) and enzymatic interesterification (EIE), the latter batch-wise (B-EIE) and in continuous (C-EIE). Better oil quality, mainly in terms of acidity, free tocopherol and partial acylglycerol content, was obtained after EIE. The clear melting point after any interesterification process was similar and about 9 °C lower as result of the modification in the TAG profile, which approaches the calculated random distribution. Interesterification changed the SFC profile significantly. For the fully refined interesterified blends, the SFC profile was similar and clearly different from the starting blend. Interesterification decreased the content of solids at temperatures >15 °C and increased the content of solids at temperatures <15 °C. This increase was less remarkable after C-EIE, suggesting that full randomization was not achieved in the used conditions, probably caused by a too short residence time of the oil in the enzymatic bed. During B-EIE, variations in SFC with time, principally at low temperatures, were still observed although the TAG composition was stable. At low temperatures, the reaction rate calculated from SFC was very low, confirming an important effect of the acyl migration on this parameter.     

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.     

Comparison of lipase-transesterified blend with some commercial solid frying shortenings in Malaysia

A transesterified experimental solid frying shortening was prepared from a palm stearin/palm kernel olein blend at 1∶1 ratio (by weight) by using Rhizomucor miehei lipase at 60°C for 6 h. The fatty acid (FA) and triacylglycerol compositions, polymorphic forms, melting and cooling characteristics, slip melting point (SMP), and solid fat content (SFC) of the transesterified blend were then compared with five commercial solid frying shortenings (three domestic and two imported) found in Malaysia. All the domestic shortenings contained nonhydrogenated palm oil or palm olein and palm stearin as the hard stock, whereas the imported frying shortenings were formulated from soybean oil and cottonseed oil and contained high level of β′ crystals. Trans FA were also found in these samples. The lipase-transesterified blend was found to be more β′-tending than the domestic samples. The SMP of the transesterified blend (47.0°C) fell within the range of the domestic samples (37.8–49.7°C) but was higher than the imported ones (42.3–43.0°C). All samples exhibited similar differential scanning calorimetry cooling profiles, with a narrow peak at the higher temperatures and a broad peak at the lower temperatures, even though their heating thermograms were quite different. Imported samples had flatter SFC curves than both the experimental and domestic samples. The domestic samples were found to have better workability or plasticity at higher temperatures than the imported ones, probably because they were formulated for a tropical climate.     

Chemical and enzymatic interesterification of tristearin/ triolein-rich blends: Chemical composition,solid fat content and thermal properties

Blends of high-oleic sunflower oil and fully hydrogenated canola oil were subjected to enzymatic and chemical interesterification using Candida antarctica lipase (5%) and sodium methoxide (0.3%), respectively. The effect of each interesterification process was determined by comparing the triacylglycerol (TAG) composition, solid fat content (SFC) profiles and thermal properties of the blends before and after interesterification. Interesterification resulted in a decrease in the concentration of triunsaturated and trisaturated TAG and an increase in the proportion of mono- and disaturated TAG. These alterations in TAG composition and the presence of a greater variety of TAG species upon interesterification was correlated with a broader melting transition by differential scanning calorimetry and, ultimately, a lower melting point for the interesterified blends. Much broader ranges in plasticity were observed for the interesterified blends (chemically and enzymatically) compared to the physical blends. Even though ideal solubility of stearin in oil was observed, the value predicted by the Hildebrand model was higher than the actual amount. Crystallization kinetic parameters (Avrami index and rate constant) were similar for the non-interesterified, enzymatically interesterified and chemically interesterified blends when compared as a function of SFC. Results from this work will aid in the formulation of more healthy fat and oil products and address a critical industrial demand in terms of formulation options for spreads, margarines and shortenings.     

Enzymatic interesterification of tallow-sunflower oil mixtures

In an effort to improve the physical and/or thermal characteristics of solid fats, the enzymatic interesterification of tallow and butterfat with high-oleic sunflower oil and soybean oil was investigated. The two simultaneously occurring reactions, interesterification and hydrolysis, were followed by high-performance liquid chromatography of altered glycerides and by gas-liquid chromatography of liberated free fatty acids. The enzymes used in these studies were immobilized lipases that included either a 1,3-acyl-selective lipase or acis-9-C₁₈-selective lipase. The degree of hydrolysis of the fat/oil mixtures was dependent upon the initial water content of the reaction medium. The extent of the interesterification reaction was dependent on the amount of enzyme employed but not on the reaction temperature over the range of 50–70°C. Changes in melting characteristics of the interesterified glyceride mixtures were followed by differential scanning calorimetry of the residual mixed glycerides after removal of free fatty acids. Interesterification of the glyceride mixes with the two types of enzymes allowed for either a decrease or increase in the solid fat content of the initial glyceride mix.     

Production of margarine fats by enzymatic interesterification with silica-granulated Thermomyces lanuginosa lipase in a large-scale study

Interesterification of a blend of palm stearin and coconut oil (75∶25, w/w), catalyzed by an immobilized Thermomyces lanuginosa lipase by silica granulation, Lipozyme TL IM, was studied for production of margarine fats in a 1- or 300-kg pilot-scale batch-stirred tank reactor. Parameters and reusability were investigated. The comparison was carried out between enzymatic and chemical interesterified products. Experimentally, Lipozyme TL IM had similar activity to Lipozyme IM for the interesterification of the blend. Within the range of 55–80°C, temperature had little influence on the degree of interesterification for 6-h reaction, but it had slight impact on the content of free fatty acids (FFA). Drying of Lipozyme TL IM from water content 6 to 3% did not affect its activity, whereas it greatly reduced FFA and diacylglycerol contents in the products. Lipozyme TL IM was stable in the 1-kg scale reactor at least for 11 batches and the 300-kg pilot-scale reactor at least for nine batches. Due to regiospecificity of the lipase (sn-1,3 specific), enzymatically interesterified products had different fatty acid distribution at sn-2 position from the chemically randomized products, implying the potential nutritional benefits of the new technology. Presented at the 91st American Oil Chemists' Society Annual Meeting in San Diego, April 28, 2000.     

Triglyceride selectivity of immobilized <Emphasis Type="Italic">Thermomyces lanuginosa</Emphasis> lipase in interesterification

The triglyceride (fatty acid) selectivity of an immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) was investigated in lipase-catalyzed interesterification reactions between two nono-acid TG in n-hexane. Tristearin (tri-C18∶0) was used as a reference in a series of TG with saturated FA from tri-C4∶0 to tri-C20∶0, except for tri-C6∶0, and in a series of unsaturated FA from tri-C18∶1 to tri-C18∶3. The quantification was performed by HPLC, and different methods of selectivity evaluation were used. None of the methods used showed any significant differences between the performances of the lipase on the different TG, indicating that Lipozyme TL IM is nonselective toward FA or TG in the system used. A response surface design was used to investigate the influence of water activities (a _w ) and reaction temperatures on the reactivity of Lipozyme TL IM with a system of tripalmitin (tri-C16∶0) and trilaurin (tri-C12∶0) in n-hexane. An increase in temperature (40 to 60°C) was found to affect the reactivity of the lipase significantly. The reactivity of Lipozyme TL IM was unaffected by the change in a _w from 0.1130 to 0.5289. An increase in a _w only led to an increase in FFA formation.     

Effect of dietary fats on desaturase activities and the biosynthesis of fatty acids in rat-liver microsomes

Four groups of rats were fed diets containing 15% (w/w) high-oleic safflower oil (SFO, rich incis-18∶1 acids), a mixture of 80% partially hydrogenated soybean oil plus 20% corn oil (H+CO, rich intrans-18∶1 acids), lard (L, rich in saturated fatty acids) and corn oil (Co, rich in 18∶2ω6). Fatty acid composition of liver microsomes and activities of the Δ⁵, Δ⁶ and Δ⁹ desaturases were determined. Microsomal Δ⁶ desaturase activity and arachidonic acid were lower in the H+CO group compared with SFO of L. No difference was found in the Δ⁵ or Δ⁶ desaturase activity of CO and SFO groups. Thus, the oleic-acid level of the SFO diet had no effect on the metabolism of 18∶2ω6. Fluorescent polarization studies, usingtrans-parinaric acid as a probe, showed no differences between the physical states of phospholipid vesicles made from lipids isolated from each group. We concluded that thetrans-18∶1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.     

Physical and chemical properties of trans-free fats produced by chemical interesterification of vegetable oil blends

Fat blends, formulated by mixing a highly saturated fat (palm stearin or fully hydrogenated soybean oil) with a native vegetable oil (soybean oil) in different ratios from 10:90 to 75:25 (wt%), were subjected to chemical interesterification reactions on laboratory scale (0.2% sodium methoxide catalyst, time=90 min, temperature=90°C). Starting and interesterified blends were investigated for triglyceride composition, solid fat content, free fatty acid content, and trans fatty acid (TFA) levels. Obtained values were compared to those of low- and high-trans commercial food fats. The interesterified blends with 30–50% of hard stock had plasticity curves in the range of commercial shortenings and stick-type margarines, while interesterified blends with 20% hard stock were suitable for use in soft tubtype margarines. Confectionery fat basestocks could be prepared from interesterified fat blends with 40% palm stearin or 25% fully hydrogenated soybean oil. TFA levels of interesterified blends were low (0.1%) compared to 1.3–12.1% in commercial food fats. Presented at the 88th AOCS Annual Meeting and Expo, May 11–14, 1997, Seattle, Washington.     

Reduction of Graininess Formation in Beef Tallow-Based Plastic Fats by Chemical Interesterification of Beef Tallow and Canola Oil

To manufacture beef tallow (BT)-based shortening and margarine with a reduced tendency to developing sandiness, BT/canola oil (CaO) blend (80:20 w/w), selected from the BT and CaO blends mixed in different ratios from 60:40 to 85:15 with 5% increments, was subjected to chemical interesterification (CIE) with sodium methoxide as the catalyst. The interesterified products were compared with the starting mixture in terms of solid fat content (SFC), and contents of high-melting point 1,3-disaturated long-chain fatty acid 2-monounsaturated long-chain fatty acid triacylglycerols (SUS TAGs) including 1,3-distearoyl-2-oleoyl-glycerol (StOSt), 1,3-dipalmitoy-2-oleoyl-glycerol (POP), and 1-palmitoyl-2-oleoyl-3-stearoyl-glycerol (POSt). Under the selected conditions: 60 °C, 0.6% CH₃ONa, 90 min, the CIE product had a SFC profile that meets suggested bakery fat requirements, besides a content of SUS TAGs which is 22.14% lower than that of the non-interesterified blend. Also the fat produced had stable β′ polymorphs, crystal morphology, crystal sizes (<20 μm), and could resist temperature fluctuations. The CIE product obtained herein has an increased potential for manufacturing bakery shortenings and margarines with reduced graininess formation, increasing the possibilities for the commercial use of BT and CaO.     

Interesterification of Lard and Soybean Oil Blends Catalyzed by Immobilized Lipase in a Continuous Packed Bed Reactor

Structured lipids (SL), formulated by blends of lard and soybean oil in different ratios, were subjected to continuous enzymatic interesterification catalyzed by an immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) in a continuous packed bed reactor. The original and interesterified blends were examined for fatty acid and triacylglycerol composition, regiospecific distribution, and solid fat content. Blends of lard and soybean oil in the proportions 80:20 and 70:30 (w/w), respectively, demonstrated a fatty acid composition, and proportions of polyunsaturated/saturated fatty acids (PUFA/SFA) and monounsaturated/polyunsaturated fatty acids (MUFA/PUFA), that are appropriate for the formulation of pediatric products. These same blends were suited for this purpose after interesterification because their sn-2 positions were occupied by saturated fatty acids (52.5 and 45.4%, respectively), while unsaturated fatty acids predominantly occupied sn-1,3 positions, akin to human milk fat. Interesterification caused rearrangement of triacylglycerol species.     

Enzymatic interesterification of palm stearin and palm kernel olein

Palm stearin (POs) and palm kernel olein (PKOo) blends were modified by enzymatic interesterification (IE) to achieve the physical properties of margarine fats. POs and PKOo are both products of the palm oil industry that presently have limited use. Rhizomucor miehei lipase (Lipozyme IM 60) was used to catalyze the interesterification of oil blends at 60°C. The progress of interesterification was monitored by following changes in triacylglyceride composition. At 60°C interesterification can be completed in 5 h. Degrees of hydrolysis obtained through IE for all blends were decreased from 2.9 to 2.0 by use of dry molecular sieves. The solid fat contents of POs/PKOo 30:70 and 70:30 interesterified blends were 9.6 and 18.1 at 20°C, and 0 and 4.1 at 35°C, respectively. The slip melting point (SMP) of POs/PKOo 30:70 was 40.0°C before interesterification and 29.9°C after IE. For POs/PKOs 70:30, SMP was 47.7 before and 37.5°C after IE. These thermal characteristics of interesterified POs/PKOo blend ratios from 30:70 to 70:30 were comparable to those of commercial margarines. Results showed that IE was effective in producing solid fats with less than 0.5% trans.