Enzymatic interesterification of structured lipids containing conjugated linoleic acid with palm stearin for possible margarine production

Structured lipids containing conjugated linoleic acid as a functional ingredient were blended with palm stearin in the ratios of 30 : 70, 40 : 60, 50 : 50, 60 : 40 and 70 : 30 (wt/wt). The blends were subjected to enzymatic interesterification by Candida antarctica lipase. After interesterification of the blends, changes in the physical properties of the products, including lower melting points and solid fat contents along with different melting behaviors, were evidenced. Analysis of triacylglycerols (TAG) of the interesterified blends showed a decrease in the concentration of high‐melting TAG. X‐ray diffraction analysis revealed, that all the reacted blends were predominantly in the β' crystal form. The mixture could be used for the formulation of margarines or other, similar products.     

Enzymatic Synthesis of Infant Formula Fat Analog Enriched with Capric Acid

A structured lipid (SL) with a substantial amount of palmitic acid at the sn‐2 position and enriched with capric acid (C), was produced in two enzymatic interesterification stages by using immobilized lipase, Lipozyme^® TL IM (Novozymes North America Inc., Franklinton, NC, USA). The substrates for the reactions were high melting point palm stearin, high oleic sunflower oil and tricaprin. The SL was characterized for total and positional fatty acid profiles, triacylglycerol (TAG) molecular species, free fatty acid content, melting and crystallization profiles. The final SL contained 20.13 mol% of total palmitic acid, of which nearly 40 % was located at the sn‐2 position. The total capric acid content was 21.22 mol%, mostly at the sn‐1 and sn‐3 positions. The predominant TAGs in the SL were oleic–palmitic–oleic, POP and CLC. The melting completion and crystallization onset temperatures of the SL were 27.7 and 6.1 °C, respectively. The yield for the overall reaction was 90 wt%. This SL might be totally or partially used in commercial fat blends for infant formula.     

Synthesis of a Cocoa Butter Equivalent by Enzymatic Interesterification of Illipe Butter and Palm Midfraction

This study aims to synthesize a cocoa butter equivalent (CBE)‐structured lipid from a blend of illipe butter (IB) and palm midfraction (PMF) by means of enzymatic interesterification using Rhizomucor miehei sn‐1,3 specific lipase, Lipozyme^® RM IM (Novozymes North America, Inc., Franklinton, NC, USA) as the biocatalyst. Physical and chemical attributes of the CBE and cocoa butter (CB) were analyzed. The synthesized CBE matched the triacylglycerol (TAG) profile range of a commercial CB and is therefore hypothesized to show similar physical and chemical characteristics to CB. The TAG profile, fatty‐acid constituents, melting and cooling behavior, polymorphism, and crystal morphology were determined using high‐performance liquid chromatography, gas chromatography, differential scanning calorimetry, X‐ray diffraction (XRD), and polarized light microscopy, respectively. Four enzymatically interesterified blends of IB:PMF at different weight ratios were analyzed for their TAG profiles, and a ratio of IB:PMF 10:3 (%, w/w) at 5% enzyme load and a reaction time of 30 min gave similar TAG results to CB. The TAG values of the IB:PMF 10:3 interesterified product (IP) were 1,3‐dipalmitoyl‐2‐oleoylglycerol at 19.1 ± 1.0%, 1‐palmitoyl‐2‐oleoyl‐3‐stearoylglycerol at 42.7 ± 1.0%, and 1,3‐distearoyl‐2‐oleoylglycerol at 29.9 ± 0.3%. The melting and the cooling profile of IP and CB showed no significant difference. XRD of IP and CB displayed similar dominant peaks at 4.6 Å, representing a β polymorph. Both CB and IP have similar granular spherulitic crystals.     

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.     

Melting and solidification characteristics of confectionery fats: Anhydrous milk fat,cocoa butter and palm kernel stearin blends

Differential scanning calorimetry measurements of crystallization and melting characteristics of commercial samples of anhydrous milk fat (AMF), cocoa butter (CB) and hydrogenated palm kernel stearin (PKS) in ternary blends were studied. Results showed that stabilization at 26°C (either for 40 h or 7 d) did not greatly affect the melting thermogram trace of PKS. However, the effect of stabilization became prominent as CB was added into the system. Deviation of measured enthalpy from the corresponding values, calculated for thermodynamically ideal blends, showed clear interaction between all three fats. At 20°C, the strongest deviation occurred at about the AMF/CB/PKS (1∶1∶1) blend, whereas at 30°C the deviation moved toward the CB/MF (1∶1) blend. The presence of 25% AMF in PKS had little effect on its solidification capability, but solidification was adversely affected with inclusion of CB.     

Enzymatic Interesterification of Coconut and High Oleic Sunflower Oils for Edible Film Application

Blends [60:40, 70:30, and 80:20 (w/w)] of coconut oil (CO) and high oleic sunflower oil (HOSO) were interesterified using immobilized enzyme, Lipozyme^® TL IM (Novozymes North America Inc., Franklinton, NC, USA). The structured lipids (SLs), referred to as interesterified products (IPs) IP60:40, IP70:30, and IP80:20, were compared to CO and HOSO for application in edible films. IPs were compared based on fatty acid profile, TAG molecular species, melting profile, moisture vapor permeability, mechanical properties, film transparency, density, and thickness. Interesterification increased oleic acid content at the sn-2 position of IPs. CO had 5.50 ± 1.67 mol% oleic acid at the sn-2 position, and when interesterified with HOSO (92.81 ± 1.10 mol% oleic acid) the amount of oleic acid significantly increased (p < 0.05) at the sn-2 position for IP60:40, IP70:30, and IP80:20 (33.86 ± 1.55, 27.34 ± 1.20, 20.61 ± 1.50 mol%), respectively. There was no significant difference between SLs, HOSO, and CO for water vapor permeability and density when applied to emulsion edible films. The HOSO film was significantly different (1.43 ± 0.27 AUmm^?1) from the rest of the SLs and CO for film transparency. IP60:40 (2.20 ± 0.22 AUmm^?1) decreased the opacity and was significantly different from HOSO and IP80:20 (2.88 ± 0.08 AUmm^?1). Tensile strength of IP60:40 was 0.39 ± 0.17 MPa which was significantly different from IP70:30, IP80:20, and HOSO. The elongation at break was significantly different for HOSO and IP60:40. IP60:40 could be used to further investigate the use of SL in edible film for sports nutrition products.     

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.     

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.     

Synthesis of cocoa butter equivalent by lipase-catalyzed interesterification in supercritical carbon dioxide

With supercritical carbon dixoide as a reaction medium, the syntheses of cocoa butter equivalent by interesterification with various lipases were investigated. The study showed that among those five lipases tested, lipase IM-20 from Mucor miehei was the most effective and specific in synthesizing this cocoa butter equivalent product by interesterification. The yields of cocoa butter equivalent are affected by pressure, substrate oil composition, solubility and co-solvent. The best reaction conditions were: reaction pressure at 1500 psi, triglyceride with high content of POP (P, palmitate; O, oleate) and POO, reaction medium with 5.0% water, and reaction temperature at 50°C. The major component of cocoa butter, POS (S, stearate), can be increased by 6.0% by adding a small amount of carbon dioxide. The yield and melting point of the purified cocoa butter equivalent are 53.0% and 34.3°C, respectively.     

Trans-free vanaspati containing ternary blends of palm oil-palm stearin-palm olein and palm oil-palm stearin-palm kernel olein

Four samples of trans-free vanaspati were made using palm oil-palm stearin-palm olein (PO-POs-POo) blends (set A) and another four samples (set B) using palm oil-palm stearin-palm kernel olein (PO-POs-PKOo). Palm stearin iodine value [iodine value (IV), 30] and soft palm stearin (IV, 44) were used in this study. The products were evaluated for their physical and chemical properties. It was observed that most of the vanaspati were granular (grainy) and had a shiny appearance. Chemical analyses indicated that vanaspati consisting of PO-POs-POo had higher IV (47.7–52.4) than the PO-POs-PKOo vanaspati (37.5–47.3). The higher IV demonstrated by set A samples was due to their higher content of unsaturated fatty acids, 46.0–50.0% compared to 36.6–45.0% in set B. Decreasing the amount of palm oil while increasing palm stearin in the formulations resulted in higher slip melting points and higher yield values. Eutectic interaction was observed in PO-POs-PKOo blends. The β′ crystalline form was predominent in PO-POs-POo samples (set A). One formulation in set B exhibited β crystallinity. From the differential scanning calorimetry thermograms, samples in set B showed a high peak at the low-melting region as well as a high peak at the high-melting region. In set A, the peak at the low-melting region was relatively lower.     

Lipozyme IM‐catalyzed interesterification for the production of margarine fats in a 1 kg scale stirred tank reactor

Lipozyme IM‐catalyzed interesterification of the oil blend between palm stearin and coconut oil (75/25 w/w) was studied for the production of margarine fats in a 1 kg scale batch stirred tank reactor. Parameters such as lipase load, water content, temperature, and reaction time were investigated. The reusability of Lipozyme IM was also studied under optimized conditions. The interesterification products were monitored by analysis of triacylglycerol profiles, the contents of diacylglycerols, free fatty acids (FFA), and solid fat contents. The contents of some triacylglycerol species, which were categorized by equivalent carbon number (ECN), namely ECN34, 36, 48, and 50, decreased by 6.0, 5.9, 5.8, and 13.7%, respectively, after enzymatic interesterification, similar to the reduction of those species after chemical interesterification, 6.6, 6.0, 7.1, and 12.9%, respectively. On the other hand, those of ECN38, 40, 42, 44, and 46 increased by 1.1, 1.6, 6.8, 16.7, and 6.5%, respectively, in comparison with the increase of those species after chemical interesterification, 0.2, 1.5, 6.5, 17.0, and 9.2%, respectively. Lipase load and reaction time had great influence on the degree of interesterification. A Lipozyme IM load of 6% was required for a reaction of 6 h and at 60 °C, to reach a stable degree of interesterification. Temperature variation in the range of 50—75 °C did not affect the reaction degree as well as the contents of diacylglycerols, but the content of FFA slightly increased with higher temperature. Addition of water to the enzyme increased the contents of diacylglycerols and FFA in the products linearly. However, it had no effect on the degree of interesterification for the first batch when the enzyme was reused. Lipozyme IM was stable in the 10‐batch test after adjusting the water content in the system. The relationship between the content of water in the system and that of FFAs in the products was evaluated and discussed.     

利用有机相酶促反应由乌桕脂生产类可可脂

研究了利用有机相酶促反应，将我国资源丰富、价格低廉的乌桕脂改良成高附加值的类可可脂的工艺，着重探讨了乌桕脂中ＰＯＰ三甘油酯与硬脂酸间的酯交换反应，并考察了温度、有机溶剂、酶浓度及底物对该反应速度及产物组成的影响，得到了一组最佳的酯交换反应条件。     

Properties of soaps derived from distilled palm stearin and palm kernel fatty acids

Soaps made from blends of distilled palm stearin (PS) and palm (PK) kernel fatty acids were evaluated for total fatty matter, sodium chloride content, moisture content, hardness, Hunter whiteness, foamability, iodine value, titer value, and acid value. Data showed that these soaps had properties similar to palm-based soaps made from distilled palm oil and palm kernel fatty acids. The soaps showed good whiteness (greater than 80%) and foamability. Total fatty matter ranged from 10–18%, sodium chloride content was 0.5%, and free caustic was 0.1% except for blend 8 containing 10 PS:90 PK, which had a free caustic of 0.03%. Initial penetration value, a reflection of soap hardness, ranged from 32–126 mm, with an average value of 54 mm. This value is within the range of the best blends of palm-based soaps (50–63 mm). There was no obvious trend observed. Penetration value, however was found to stabilize after a month of storage with an average value of 19.4 mm. Soap with this hardness value is relatively hard and therefore should be blended with a small amount of soft oils.     

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.     

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.     

Crystallization kinetics of palm stearin in blends with sesame seed oil

This study investigates the crystallization kinetics of palm stearin (PS), a palm oil fraction, in blends with sesame seed oil. The results indicate that the crystallization behavior of PS in sesame oil is mainly associated with the crystallization of tripalmitin. Therefore, crystallization of blends of 26, 42, 60, and 80% (wt/vol) PS in sesame oil was described by equations developed for simpler systems (e.g., Fisher and Turnbull equation). The isothermal crystallization, melting profile, and fitting of the kinetics of nucleation to the Fisher and Turnbull equation showed that the 26, 42, and 60% PS/sesame oil blends crystallized mainly in the β₁′ polymorph state. In contrast, the 80% blend crystallized in two different polymorph states (i.e., β₁′ at T⪯307.6 K and β₁ at T≽308.2 K). The data indicated that, in spite of the higher concentration of PS in the 80% PS/sesame oil system, crystallization in the β₁ state required more free energy for nucleation (δG _c ) than β₁′ crystallization in the 26, 42, and 60% PS/sesame oil. At the low cooling rate used (1 K/min) it was observed that, for a particular PS blend, the higher the effective supercooling the higher the viscosity of the oil phase and the smaller the induction time of crystallization (T_i). Additionally, the β₁′ crystals from PS, developed at the highest effective supercooling investigated, were smaller than the β₁ crystals obtained at lower effective supercooling.     

Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil

One of the major difficulties in using crude vegetable oils as substitute fuels in diesel engines is their relatively high viscosities. Increasing the temperature of the crude vegetable oil, blending it with diesel oil, or the combination of both offers a simple and effective means of controlling and lowering the viscosities of vegetable oils. This work reports viscosity data, determined with a rotational bob-and-cup viscometer, for crude palm oil and cononut oil blended with diesel oil over the temperature range of 20–80°C and for different mixture compositions. All the test oil samples showed a time-independent newtonian type of flow behavior. The reduction of viscosity with increasing liquid temperature followed an exponential relationship, with the two constants of the equation being a function of the volume percentage of the vegetable oil in the mixture. A single empirical equation was developed for predicting the viscosity of these fuel mixtures under varying temperatures and blend compositions.