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.     

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.     

Pattern recognition of lipase‐catalyzed or chemically interesterified fat blends containing n‐3 polyunsaturated fatty acids

The feasibility to discriminate among samples of different fat blends prior and after inorganic or lipase‐catalyzed interesterification, via pattern recognition techniques [principal component analysis (PCA) and discriminant analysis (DA)], was investigated. Blends I and II, consisting of mixtures of palm stearin, palm kernel oil and a concentrate of triacylglycerols (TAG) rich in n‐3 polyunsaturated fatty acids (EPAX 4510TG or EPAX 2050TG) were used. These blends, prior (64 samples) and after interesterification, catalyzed by an immobilized Thermomyces lanuginosa lipase (Lipozyme TL IM, 54 samples) or by sodium methoxide (10 samples), were characterized by their acylglycerol profiles (25 chromatographic peaks) and solid fat content (SFC) at 10, 20, 30 and 35 °C. PCA on the multivariate data (i) showed that the initial samples were characterized by higher SFC and higher contents of high‐melting TAG and (ii) suggested two separate clusters of initial and interesterified samples. DA was performed on the multivariate data to determine which of the 29 variables have discriminative power. When the 124 samples, characterized by their acylglycerols, were grouped into (i) initial and interesterified samples of blends I or II (four groups) or (ii) also by the catalyst used (six groups), 98.4% of the samples were correctly classified.     

<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.     

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.     

Zero‐Trans Cake Shortening: Formulation and Characterization of Physicochemical,Rheological, and Textural Properties

Cake shortening is an important ingredient that imparts taste and texture in the cake as the final product. Hydrogenated shortenings contain high amounts of trans fatty acids, which is considered a risk factor for obesity, cancers, and cardiovascular diseases. In this research, chemically interesterified blends of canola oil (CO) and palm stearin (PS) were recruited in order to formulate zero‐trans shortening, specifically for cake application. The optimization of shortening formulation was performed by Design‐Expert software, considering melting, congelation, textural, and rheological properties of cake shortening as responses. The formulated shortening in the weight ratio of 66.41:33.58 (PS:CO) (%, w/w) was analyzed and compared with two commercial cake shortenings in terms of fatty acid and triacylglycerol composition, slip melting point (SMP), solid fat content (SFC), and rheological and textural properties. The results showed that the formulated zero‐trans cake shortening with 0.2% trans, 47.2% saturated fatty acids, SMP of 40.9 °C, SFC of 10.51% at 37 °C, firmness of 1522.5 g, and linear viscoelastic range of 0.035% had the most acceptable criteria among cake‐shortening samples. The findings of this study offer insights into the relationship between shortening functionality and physicochemical properties and serve as a base for future studies on zero‐trans shortenings formulation.     

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.     

Effect of enzymatic transesterification with flaxseed oil on the high-melting glycerides of palm stearin and palm olein

The effects of enzymatic transesterification on the melting behavior of palm stearin and palm olein, each blended separately with flaxseed oil in the ratio of 90∶10 and catalyzed by various types of lipases, were studied. The commercial lipases used were Lipozyme IM, Novozyme 435, and myceliumbound lipases of Aspergillus flavus and A. oryzae. The slip melting point (SMP) of the palm stearin/flaxseed oil (PS/FS) mixture transesterified with lipases decreased, with the highest drop noted for the mixture transesterified with Lipozyme IM. However, when palm stearin was replaced with palm olein, the SMP of the palm olein/flaxseed oil (PO/FS) mixture increased, with the commercial lipases causing an increase of 41 to 48% compared to the nontransesterified material. As expected, the solid fat content (SFC) of the transesterified PS/FS was lower at all temperatures than that of the nontransesterified PS/FS sample. In contrast, all transesterified PO/FS increased in SFC, particularly at 10°C. Results from DSc and HPLC analyses showed that the high-melting glycerides, especially the tripalmitin of palm stearin, were hydrolyzed. Consequently, 1,3-dipalmitoylglycerol was found to accumulate in the mixture. There was no difference in the FA compositions between the transesterified and nontransesterified mixtures.     

Operational stability of Thermomyces lanuginosa lipase during interesterification of fat in continuous packed‐bed reactors

The operational stability of a commercial immobilized lipase from Thermomyces lanuginosa (“Lipozyme TL IM”) during the interesterification of two fat blends, in solvent‐free media, in a continuous packed‐bed reactor, was investigated. Blend A was a mixture of palm stearin (POS), palm kernel oil (PK) and sunflower oil (55 : 25 : 20, wt‐%) and blend B was formed by POS, PK and a concentrate of triacylglycerols rich in n‐3 polyunsaturated fatty acids (PUFA) (55 : 35 : 10, wt‐%). The bioreactor operated continuously at 70 °C, for 580 h (blend A) and 390 h (blend B), at a residence time of 15 min. Biocatalyst activity was evaluated in terms of the decrease of the solid fat content at 35 °C of the blends, which is a key parameter in margarine manufacture. The inactivation profile of the biocatalyst could be well described by the first‐order deactivation model: Half‐lives of 135 h and 77 h were estimated when fat blends A and B, respectively, were used. Higher levels of PUFA in blend B, which are rather prone to oxidation, may explain the lower lipase stability when this mixture was used. The free fatty acid content of the interesterified blends decreased to about 1% during the first day of operation, remaining constant thereafter.     

D. K. Bhattacharyya,Modification of tallow fractions in the preparation of edible fat products

Investigation has been carried out with an intention to prepare shortening, margarine fat bases, and value-added edible fat products like cocobutter substitute from tallow. For this, tallow was fractionated at low (12 and 15 °C) and intermediate (25 °C) temperatures by solvent (acetone) fractionation process. The stearin fractions (yield: 23—40% (w/w) and slip melting point: 45—50.5 °C) thus obtained were blended and interesterified with liquid oils, such as sunflower, soybean, rice bran etc. by microbial lipase catalyzed route. The olein fractions (yield: 60—77% (w/w) and slip melting point: 21—32.5 °C) were also chemically interesterified (using NaOMe) and biochemically (using Rhizomucor miehei lipase, Lipozyme IM 20). The olein fractions were also blended with sal (Shorea robusta) fat, sal olein, and acidolysed karanja (Pongamia glabra) stearin. As revealed from their slip melting point and solid fat index, the products thus prepared were found to be suitable for shortening, margarine fat bases, and vanaspati substitute.     

Cocoa Butter Alternatives from Enzymatic Interesterification of Palm Kernel Stearin,Coconut Oil,and Fully Hydrogenated Palm Stearin Blends

Structured lipids (SL) were produced from enzymatic interesterification (EIE) of palm kernel stearin (PKS), coconut oil (CNO), and fully hydrogenated palm stearin (FHPS) blends in various mass ratios. The EIE reactions were performed at 60 °C for 6 hours using immobilized Lipozyme RM IM with a mixing speed of 300 rpm. The physicochemical properties, crystallization and melting behavior, solid fat content (SFC), crystal morphology and polymorphism of the physical blends (PB), and the SL were characterized and compared with commercial cocoa butter and cocoa butter alternatives (CBA). EIE significantly modified the triacylglycerol compositions of the fat blends, resulting in changes in the physical properties and the crystallization and melting behavior. SFC and slip melting point of all SL decreased from those of their counterpart PB. In particular, SL obtained from EIE of blends 60:10:30 and 70:10:20 (PKS:CNO:FHPS) exhibited a high potential to be used as trans-free CBA as they showed similar melting ranges, melting peak temperatures, and SFC curves to the commercial CBA with fine needle-like crystals and desirable β' polymorph.     

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.     

Enzymatic Interesterification of Lauric Fat Blends Formulated by Grouping Triacylglycerol Melting Points

Lauric fat blends (appreciable amount of lauric fat with liquid oil and hard fat) initially formulated for shortening production by grouping triacylglycerol (TAG) melting points were further modified by enzymatic interesterification (EIE) to improve their key functionalities as plastic fats. At a similar fat blend formulation, only the high melting fat and medium melting fat were interesterified in binary‐EIE. Meanwhile, both fats and the liquid oil were interesterified in ternary‐EIE. The solid fat content (SFC) of all binary‐EIE blends was generally retained as similar in the temperature range between 0 and 20 °C when the amount of unsaturated TAGs was limited by excluding the liquid oil during EIE. However, the SFC was significantly reduced at temperatures above 20 °C compared to that of the initial blends. Furthermore, the melting point of binary‐EIE blends at BH50H15 formulation prepared with palm stearin and fully hydrogenated rapeseed oil as the hard fat was found to be drastically reduced from 54.6 to 35.3 °C and from 62.8 to 39.2 °C, respectively. In contrast, the SFC of ternary‐EIE blends was generally reduced when more unsaturated TAGs were available for EIE by including the liquid oil. However, higher SFC was noticed at temperatures around 10 °C in ternary‐EIE blends, as the amount of high‐melting fractions in their initial blends was increased from BH50H5 to BH50H15. Eventually, both binary and ternary‐EIE were also found to significantly alter the crystal microstructure of lauric fat blends, in terms of crystal morphology, size and network density.     

Application of palm olein in the production of zero‐trans Iranian vanaspati through enzymatic interesterification

The utilization of palm olein in the production of zero‐trans Iranian vanaspati through enzymatic interesterification was studied. Vanaspati fat was made from ternary blends of palm olein (POL), low‐erucic acid rapeseed oil (RSO) and sunflower oil (SFO) through direct interesterification of the blends or by blending interesterified POL with RSO and SFO. The slip melting point (SMP), the solid fat content (SFC) at 10–40 °C, the carbon number (CN) triacylglycerol (TAG) composition, the induction period (IP) of oxidation at 120 °C (IP₁₂₀) and the IP of crystallization at 20 °C of the final products and non‐interesterified blends were evaluated. Results indicated that all the final products had higher SMP, SFC, IP of crystallization and CN 48 TAG (trisaturated TAG), and lower IP₁₂₀, than their non‐interesterified blends. However, SMP, SFC, IP₁₂₀, IP of crystallization and CN 48 TAG were higher for fats prepared by blending interesterified POL with RSO and SFO. A comparison between the SFC at 20–30 °C of the final products and those of a commercial low‐trans Iranian vanaspati showed that the least saturated fatty acid content necessary to achieve a zero‐trans fat suitable for use as Iranian vanaspati was 37.2% for directly interesterified blends and 28.8% for fats prepared by blending interesterified POL with liquid oils.     

Plastic fats with zero trans fatty acids by interesterification of mango,mahua and palm oils

Speciality plastic fats with no trans fatty acids suitable for use in bakery and as vanaspati are prepared by interesterification of blends of palm hard fraction (PSt) with mahua and mango fats at various proportions. It was found that the interesterified samples did not show significant differences in solid fat content (SFC) after 0.5 or 1 h reaction time. The blends containing PSt/mahua (1:1) showed three distinct endotherms, indicating a heterogeneity of triacylglycerols (TG), the proportions of which altered after interesterification. The SFC also showed improved plasticity after interesterification. Similar results were observed with other blends of PSt/mahua (1:2). These changes in melting behavior are due to alterations in TG composition, as the trisaturated‐type TG were reduced and the low‐melting TG increased after interesterification. The blends containing PSt/mango (1:1) showed improvement in plasticity after interesterification, whereas those containing PSt/mango (2:1) were hard and showed high solid contents at higher temperature and hence may not be suitable for bakery or as vanaspati. The blends with palm and mahua oils were softer and may be suitable for margarine‐type products. The results showed that the blends of PSt/mahua (1:1, 1:2) and PSt/mango (1:1) after interesterification for 1 h at 80 °C showed an SFC similar to those of commercial hydrogenated bakery shortenings and vanaspati. Hence, they could be used in these applications in place of hydrogenated fats as they are free from trans acids, which are reported to be risk factors involved in coronary heart disease. For softer consistency like margarine applications, the blends containing palm oil and mahua oil are suitable.     

Chemical and enzymatic interesterification of a beef tallow and rapeseed oil equal‐weight blend

A mixture of beef tallow and rapeseed oil (1:1, wt/wt) was interesterified using sodium methoxide or immobilized lipases from Rhizomucor miehei (Lipozyme IM) and Candida antarctica (Novozym 435) as catalysts. Chemical interesterifications were carried out at 60 and 90 °C for 0.5 and 1.5 h using 0.4, 0.6 and 1.0 wt‐% CH₃ONa. Enzymatic interesterifications were carried out at 60 °C for 8 h with Lipozyme IM or at 80 °C for 4 h with Novozym 435. The biocatalyst doses were kept constant (8 wt‐%), but the water content was varied from 2 to 10 wt‐%. The starting mixture and the interesterified products were separated by column chromatography into a pure triacylglycerol fraction and a nontriacylglycerol fraction, which contained free fatty acids, mono‐, and diacylglycerols. It was found that the concentration of free fatty acids and partial acylglycerols increased after interesterification. The slip melting points and solid fat contents of the triacylglycerol fractions isolated from interesterified fats were lower compared with the nonesterified blends. The sn‐2 and sn‐1,3 distribution of fatty acids in the TAG fractions before and after interesterification were determined. These distributions were random after chemical interesterification and near random when Novozym 435 was used. When Lipozyme IM was used, the fatty acid composition at the sn‐2 position remained practically unchanged, compared with the starting blend. The interesterified fats and isolated triacylglycerols had reduced oxidative stabilities, as assessed by Rancimat induction times. Addition of 0.02% BHA and BHT to the interesterified fats improved their stabilities.     

利用脂肪酶催化酯交换制备棕榈油基人造奶油基料

文章考察了Lipozyme TL IM脂肪酶在无溶剂条件下,催化棕榈油硬脂与棕榈油软脂的酯交换。混合油为棕榈油硬脂和棕榈油软脂的比例为75∶25,脂肪酶的添加量为油重量的4%,酶催化反应的操作温度为70℃,反应时间为20 h。酯交换产物的氧化稳定性更高,SFC35℃降低了24.79%,改善了酯交换油的打发性,提高了人造黄油的可操作性及口感。     

Utilization of high-melting palm stearin in lipase-catalyzed interesterification with liquid oils

Palm stearin with a melting point (m.p.) of 49.8°C was fractionated from acetone to produce a low-melting palm stearin (m.p.=35°C) and a higher-melting palm stearin (HMPS, m.p.=58°C) fraction. HMPS was modified by interesterification with 60% (by weight) of individual liquid oils from sunflower, soybean, and rice bran by means of Mucor miehei lipase. The interesterified products were evaluated for m.p., solid fat content, and carbon number glyceride composition. When HMPS was interesterified individually with sunflower, soybean or rice bran at the 60% level, the m.p. of the interesterified products were 37.5, 38.9, and 39.6°C, respectively. The solid fat content of the interesterified products were 30–35 at 10°C, 17–19 at 20°C, and 6–10 at 30°C, respectively. The carbon number glyceride compositions also changed significantly. C₄₈ and C₅₄ glycerides decreased remarkably with a corresponding increase of the C₅₀ and C₅₂ glycerides. All these interesterified products were suitable for use as trans acid-free and polyunsaturated fatty acid-rich shortening and margarine fat bases.     

Plastic fats and margarines through fractionation,blending and interesterification of milk fat

Milk fat stearins and oleins were blended with high‐ and low‐melting natural fats to produce plastic fats, vanaspati substitute and confectionery fats. Margarines of improved nutritional value were also formulated. Fractionation was carried out using acetone, hexane, and isopropyl alcohol. The yield (wt‐%) of high‐melting stearin (HMS) from acetone and IPA was 13.0 ± 0.2 to 13.3 ± 0.1 after crystallization for 24 h at 20 °C. The melting point of the products was 49.0 ± 0.5 to 49.8 ± 0.6 °C. However, in hexane the yield of HMS was 12.2 ± 0.2% at 10 °C. The olein fractions were further fractionated at 10 °C from acetone and IPA, and at 0 °C from hexane, to obtain superoleins and low‐melting stearins (LMS). HMS fractions were blended with rice bran oil and cottonseed oil at the ratio 70 : 30 (wt/wt), and the superoleins were blended with sal fat and palm stearin at the ratios 40 : 60, 30 : 70 and 20 : 80 (wt/wt). The blends were interesterified (product melting point: 22.7 ± 0.04 to 39.3 ± 0.10 °C) chemically and enzymatically to prepare margarine. The penetration values (in 0.1 mm) of these margarines were noted to be 112 ± 1.52 to 145 ± 0.00.     

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.