Physical and Chemical Properties of Randomly Interesterified Blends of Corn Oil and Tallow

The sodium methylate-catalyzed random interesterification of corn oil-tallow blends was explored in order to develop plastic fats of varying physical properties. Lipase hydrolysis of the randomized fats showed that with 0.5% catalyst, interesterification was completed within 30 min at 80°C. Interesterification decreased the melting point and solid fat index of the randomized fats. The trans- fatty acid level and fatty acid profile of the rearranged fats did not show any change upon interesterification. The oxidative stability of the fats decreased after random interesterification, but addition of 0.01% citric acid and 0.01% butylated hydroxyanisole produced a fat blend of comparable stability to commercial margarine oils.     

The interesterification-induced changes in olive and palm oil blends

Refined olive oil and partially hydrogenated palm oil (PHPO) blends of varying proportions were subjected to both chemical and enzymatic interesterifications. The rearranged fats were investigated for their melting points, solid fat contents at selected temperatures, fatty acid compositions and trans isomer contents, as well as evaluations, by an expert sensory panel, of their spreadibility and appearance characteristics. The analytical results were compared with those of commercial Turkish margarines. The 30:70 olive oil-PHPO blend after enzymatic interesterification was found to have properties very similar to those of Turkish package margarines, with the additional advantage of possessing higher amounts of monounsaturated fatty acids.     

Structured lipids obtained by chemical interesterification of olive oil and palm stearin

Interesterification of palm stearin (PS) with liquid vegetable oils could yield a good solid fat stock that may impart desirable physical properties, because PS is a useful source of vegetable hard fat, providing β′ stable solid fats. Dietary ingestion of olive oil (OO) has been reported to have physiological benefits such as lowering serum cholesterol levels. Fat blends, formulated by binary blends of palm stearin and olive oil in different ratios, were subjected to chemical interesterification with sodium methoxide. The original and interesterified blends were examined for fatty acid and triacylglycerol composition, melting point, solid fat content (SFC) and consistency. Interesterification caused rearrangement of triacylglycerol species, reduction of trisaturated and triunsaturated triacylglycerols content and increase in diunsaturated-monosaturated triacylglycerols of all blends, resulting in lowering of melting point and solid fat content. The incorporation of OO to PS reduced consistency, producing more plastic blends. The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of palm stearin and olive oil.     

Effects of chemical interesterification on physicochemical properties of blends of palm stearin and palm olein

Chemical interesterification is an important technological option for the production of fats targeting commercial applications. Fat blends, formulated by binary blends of palm stearin and palm olein in different ratios, were subjected to chemical interesterification. The following determinations, before and after the interesterification reactions, were done: fatty acid composition, softening point, melting point, solid fat content and consistency. For the analytical responses a multiple regression statistical model was applied. This study has shown that blending and chemical interesterifications are an effective way to modify the physical and chemical properties of palm stearin, palm olein and their blends. The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of palm stearin and palm olein.     

Effects of interesterification and fatty acid supplementation on the digestibility of tallow in milk replacers for calves

The effects of interesterification and fatty acid supplementation on the nutritive value of homogenised fats in milk replacers for calves were studied in two digestibility experiments, each of a 6 × 6 latin square design. Using a level of 20% added fat, the mean apparent digestibilities of the total dietary lipids were: butterfat, 96.5%; interesterified butterfat, 95.5%; tallow, 88.7%; interesterified tallow, 93.1%; tallow supplemented with trimyristin and triolein by interesterification, 92.3%; tallow supplemented with trimyristin and triolein by simple admixture, 89.9%. The high digestibility of butterfat is not dependent apparently on any specific non-random distribution of its constituent fatty acids. The digestibility of the tallow was lower and interesterification just failed to give a significant improvement. The inclusion of additional myristic and oleic acids had no significant effect. Using a level of 15% added fat, the mean apparent digestibilities of the total dietary lipids were: tallow, 79.7%; interesterified tallow, 89.2%; interesterified, reduced stearic acid, tallow 87.9%; interesterified, reduced stearic acid, added butyric acid, tallow, 96.3%; interesterified, added butyric acid, tallow 94.7%; tallow admixed with tributyrin, 84.0%. The inclusion in tallow of butyric acid by a process involving interesterification resulted in substantial increases in digestibility to values similar to those obtained for butterfat and interesterified butterfat in the first experiment. The improvement was not achieved by simple admixture of tributyrin with tallow. Reduction of the stearic acid content in tallow to a level similar to that in butterfat had no significant effect on fat digestibility. The lower digestibility of tallow than of butterfat was due mainly to lower digestibility of palmitic and stearic acids and a higher percentage of the latter acid in tallow. Modifications which effected an improvement in the digestibility of tallow generally did so by improving the digestibility of these acids.     

<Emphasis Type="Italic">Trans</Emphasis>-free margarine fat produced using enzymatic interesterification of rice bran oil and hard palm stearin

Trans-free interesterified fats were prepared from blends of hard palm stearin (hPS) and rice bran oil (RBO) at 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, and 80:20 weight % using immobilized Mucor miehei lipase at 60°C for 6 h with a mixing speed of 300 rpm. Physical properties and crystallization and melting behaviors of interesterified blends were investigated and compared with commercial margarine fats. Lipase-catalyzed interesterification modified triacylglycerol compositions and physical and thermal properties of hPS:RBO blends. Slip melting point and solid fat contents (SFC) of all blends decreased after interesterification. Small, mostly β′ form, needle-shaped crystals, desirable for margarines were observed in interesterified fats. Interesterified blend 40:60 exhibited an SFC profile and crystallization and melting characteristics most similar to commercial margarine fats and also had small needle-like β′ crystals. Interesterified blend 40:60 was suitable for use as a transfree margarine fat.     

Enzymatic interesterification of anhydrous butterfat with flaxseed oil and palm stearin to produce low-trans spreadable fat

Lipase-catalysed interesterification was performed to produce low-trans spreadable fat (LTSF) with anhydrous butterfat (ABF), flaxseed oil (FSO), and palm stearin (PS) using biocatalysts (Lipozyme RM IM and Novozym SP435). The reaction was carried out for 24 h at 60 °C in a shaking water bath (180 rpm). Seven substrate blends for the production of LTSF were prepared: 12:6:2, 10:6:4, 9:6:6, 8:6:6, 6:6:8, 6:6:9, and 4:6:10 (ABF/PS/FSO, by weight). After 24-h interesterification, decreased saturated fatty acid (SFA) contents in LTSFs were observed with ranges from 67% to 41%. LTSFs exhibited low atherogenic index (AI) with ranges from 2.8 to 0.8, compared with 3.3–4.7 AI of butter fat. Equivalent carbon number (ECN) 42–46 in the newly produced triacylglycerol (TAG) increased according to rearrangement of FAs on TAG backbone. The α-linolenic acid contents (mol%) of each LTSF were 5.6% (12:6:2), 10.7% (10:6:4), 15.1% (9:6:6), 15.8% (8:6:6), 20.8% (6:6:8), 22.4% (6:6:9) and 26% (4:6:10). The trans fatty acids in the LTSFs was not more than 2%. Melting point ranges of LTSF were from 37 (9:6:6) to 32 °C (4:6:10).     

Edible lipids modification processes: A review

Lipid is the general name given to fats and oils, which are the basic components of cooking oils, shortening, ghee, margarine, and other edible fats. The chosen term depends on the physical state at ambient temperature; fats are solids and oils are liquids. The chemical properties of the lipids, including degree of saturation, fatty acid chain length, and acylglycerol molecule composition are the basic determinants of physical characteristics such as melting point, cloud point, solid fat content, and thermal behavior. This review will discuss the major lipid modification strategies, hydrogenation, and chemical and enzymatic interesterification, describing the catalysts used mechanisms, kinetics, and impacts on the health-related properties of the final products. Enzymatic interesterification will be emphasized as method that produces a final product with good taste, zero trans fatty acids, and a low number of calories, requires less contact with chemicals, and is cost efficient.     

Production of trans‐free margarine stock by enzymatic interesterification of rice bran oil,palm stearin and coconut oil

BACKGROUND: Trans‐free interesterified fat was produced for possible usage as a spreadable margarine stock. Rice bran oil, palm stearin and coconut oil were used as substrates for lipase‐catalyzed reaction. RESULTS: After interesterification, 137–150 g kg^?1 medium‐chain fatty acid was incorporated into the triacylglycerol (TAG) of the interesterified fats. Solid fat contents at 25 °C were 15.5–34.2%, and slip melting point ranged from 27.5 to 34.3 °C. POP and PPP (β‐tending TAG) in palm stearin decreased after interesterification. X‐ray diffraction analysis demonstrated that the interesterified fats contained mostly β′ polymorphic forms, which is a desirable property for margarines. CONCLUSIONS: The interesterified fats showed desirable physical properties and suitable crystal form (β′ polymorph) for possible use as a spreadable margarine stock. Therefore, our result suggested that the interesterified fat without trans fatty acid could be used as an alternative to partially hydrogenated fat. Copyright © 2010 Society of Chemical Industry     

The influence of chemical modification on the hydrolysis of fats by pancreatic lipase and pregastric esterase with reference to fat digestion in the pre-ruminant calf

The hydrolysis of various dietary fats and pure triglycerides by pregastric esterase and pancreatic lipase was studied in vitro in conjunction with a series of digestibility trials to examine the effect of various chemical modifications to beef tallow on its digestibility in milk replacers for pre-ruminant calves. Using pure triglycerides, it was shown that pregastric esterase preferentially hydrolyses triglycerides containing short chain fatty acids; the rate was highest with glyceryl tributyrate and decreased markedly with increase in chain length. Using butterfat, tallow and various modified forms of tallow, it was shown that the inclusion of butyric acid in tallow by interesterification, which markedly improved its digestibility, substantially increased its rate of hydrolysis by pregastric esterase. The initial rate of hydrolysis of tallow by pancreatic lipase was substantially less than that of butterfat. Little improvement in the rate of hydrolysis and solubilisation was obtained when the tallow sample was interesterified or when it was supplemented with the long chain fatty acids, myristic and oleic, or with the short chain fatty acid, butyric. A considerable increase in the initial rate of hydrolysis and solubilisation did occur with tallow samples with a reduced content of stearic acid. The results suggest that hydrolysis by pregastric esterase is a major site of discrimination between different fats in the pre-ruminant calf and an important factor in determining overall digestibility.     

The effects of enzymatic interesterification on the physical-chemical properties of blends of lard and soybean oil

The main goal of the present research effort was to evaluate the physical-chemical properties of blends of lard and soybean oil following enzymatic interesterification catalyzed by an immobilized lipase from Thermomyces lanuginosa (Lipozyme™ TL IM). Lipase-catalyzed interesterification produced new triacylglycerols that changed the physical-chemical properties of the fat blends under study. Solid fat content (31.3 vs 31.5 g/100 g), consistency (104.7 vs 167.6 kPa), crystallized area (0.6 vs 11.8) and softening point (31.8 vs 32.2 °C) of lard increased after interesterification, and this was mostly due to the increase of SSS (saturated) + SSU (disaturated-monounsaturated) triacylglycerols. These contents (SSU + SSS) increased in lard after interesterification from 42.9 to 46.7 g/100 g. The interesterified blends exhibited lower values for the physical properties when compared with their counterparts before enzymatic interesterification. The interesterification of blends of lard with soybean oil increased the amounts of UUU (triunsaturated) and SSS triacylglycerols and reduced the amounts of UUS (diunsaturated-monosaturated) triacylglycerols. The interesterified blends of lard and soybean oil demonstrated physical properties and chemical composition similar to human milk fat and they could be used for the production of a human milk fat substitute.     

An investigation on the physicochemical characterization of interesterified blends of fully hydrogenated palm olein and soybean oil

In this study, the effect of interesterification (using sodium methoxide) on physicochemical characteristics of fully hydrogenated palm olein (FHPO)/soybean oil blends (10 ratios) was investigated. Interesterification changed free fatty acid content, decreased oil stability index, solid fat content (SFC) and slip melting point (SMP), and does not affected the peroxide value. With the increase of FHPO ratio, oil stability index, SFC and SMP increased in both the interesterified and non-interesterified blends. Fats with higher FHPO ratio had narrower plastic range, as well. Compared to the initial blends, interesterified fats had wider plastic ranges at lower temperatures. Both the non-interesterified and interesterified blends showed monotectic behavior. The Gompertz function could describe SFC curve (as a function of temperature, saturated fatty acid (SFA) content or both) and SMP (as a function of SFA) of the interesterified fats with high R² and low mean absolute error.     

MELTING CHARACTERISTIC AND SOLID FAT CONTENT OF MILK FAT AND PALM STEARIN BLENDS BEFORE AND AFTER ENZYMATIC INTERESTERIFICATION

Melting characteristics and solid fat content of anhydrous milk fat (AMF), soft palm oil stearin (SPOs), hard palm oil stearin (HPOs) and their blends were studied by differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy, respectively. Solid fat contents (SFC) determined by NMR were used to construct isosolid diagrams; these indicated the presence of an eutectic effect along the binary blends of AMF:SPOs which only could be observed at 5 and 10C. The effect was reduced after interesterification by sn-1,3-specific lipase. The modification also reduced the number of the distinct DSC melting peaks, demonstrating a better miscibility among the blended fats. A substantial decrease in DSC melting enthalpy of interesterified blends was found to be parallel to a decrease in SFC that was observed at 25–40C. Fatty acid composition showed that improved functionality of AMF may be due to an enrichment in long-chain saturated fatty acids contributed both by SPOs and HPOs.     

Fatty acid composition and characteristics of Pentadesma butyracea fat extracted from ghana seeds

Recent interest in the development of the tallow tree (Pentadesma butyracea S) as an oil-tree crop has stimulated agronomic and chemical studies of the tree and the fat obtained from its seeds. Tallow fat extracted from local seeds has been analysed for its chemical and physical constants and fatty acid composition. These characteristics have been compared with those of the better known cocoa butter and shea butter. Dry tallow kernels, shea butter kernels and cocoa beans contained 50, 52.1 and 53.4% fat, respectively. Tallow fat and shea butter are similar in several of their characteristics, particularly slip point, saponification number, solidification point and fatty acid composition; but tallow fat has a much lower unsaponifiable matter content (1.5–1.8%) than shea butter (7.3–9.0%). Both are markedly different from cocoa butter and cocoa butter replacement fats in respect of their melting points and fatty acid composition. Cooling curves of 3:1, 1:1, and 1:3 mixtures of tallow fat and cocoa butter indicate poor compatibility between the two fats.     

Effects of chemical interesterification on solid fat content and slip melting point of fat/oil blends

Fat/oil blends, formulated by mixing fully hydrogenated palm oil stearin or palm oil stearin with vegetable oils (canola oil and cottonseed oil) in different ratios from 30:70 to 70:30 (w/w %), were subjected to chemical interesterification reactions on a laboratory scale. Fatty acid (FA) composition, iodine value, slip melting point (SMP) and solid fat content (SFC) of the starting blends were analysed and compared with those of the interesterified blends. SMPs of interesterified blends were decreased compared to starting blends because of extensive rearrangement of FAs among triacylglycerols. These changes in SMP were reflected in the SFCs of the blends after the interesterification. SFCs of the interesterified blends also decreased with respect to the starting blends, and the interesterified products were softer than starting blends. These interesterified blends can be used as an alternative to partial hydrogenation to produce a plastic fat phase that is suitable for the manufacture of margarines, shortenings and confectionary fats.     

Enzymatic interesterification of palm and coconut stearin blends

Hard fractions of palm oil and coconut oil, blended in the ratios of 90:10, 85:15, 80:20 and 75:25, were interesterified for 8 h using Lipozyme TL IM. Major fatty acids in the blends were palmitic acid (41.7–48.4%) and oleic acid (26.2–30.8%). Medium‐chain fatty acids accounted for 4.5–13.1% of the blends. After interesterification (IE), slip melting point was found to decrease from 44.8–46.8 °C to 28.5–34.0 °C owing to reduction in solids content at all temperatures. At 37.5 °C, the blends containing 25% coconut stearins had 17.4–19% solids, which reduced to 0.4–1.5% on IE, and the slip melting point (28.6 and 28.8 °C) indicated their suitability as margarine base. The reduction in solid fat index of the interesterified fats is attributed to the decrease in high‐melting triacylglycerols in palm oil (GS₃ and GS₂U type) and increase in triolein (GU₃) content from 1 to 9.2%. Retention of tocopherols and β‐carotene during IE was 76 and 60.1%, respectively, in 75:25 palm stearin and coconut stearin blend.     

Rheological and crystalline properties of trans-free model fat blends as affected by the length of fatty acid chains

Three structured fats were prepared by the total catalytic hydrogenation and random chemical transesterification using medium (coconut oil) and long (palmstearine, low and high erucic rapeseed oil) chain saturated fatty acids triglycerides. All three structured fats crystallized in β′ modification and had the same solid fat content profile. Hardness was dependent on the type of long chain fatty acid (palmitic, stearic and behenic) in structured fat. Molar ratio of medium:long chain fatty acids was 2:1. Model fat blends prepared on the base of these structured fats had the same solid fat content profile (at constant content of structured fat). Yield stress of the fat blends was dependent on the content and mainly on the composition of structured fat. None of the model fat blends crystallized in β modification. The substitution of the stearic–palmitic by stearic or by stearic–behenic acids in the structured fats appears possible.     

Influence of triglycerides and free fatty acids in milk replacers on calf performance, blood plasma, and adipose lipids

In a 4-wk study of 48 3-day-old calves we compared effects of feeding various fats or their free fatty acids in skim milk-powder based milk replacer, on calf performance, feed utilization, and blood plasma and adipose lipids. When fat was fed, calf performance and feed utilization were equivalent for tallow and coconut oil diets but markedly poorer for corn oil. Complete replacement (tallow) or one-half replacement (coconut and corn oils) of the fats with their free fatty acids reduced calf gains and feed efficiency. Tallow free fatty acids gave lower digestibilities of palmitic and stearic acid and reduced calcium absorption. Free fatty acids from both coconut and corn oils reduced diet palatability and intake; those from tallow and coconut oil markedly interfered (in vitro) with rennet clotting of milk replacers. The main lipid classes in blood plasma for all treatments were cholesteryl esters and phosphatidylcholine. High concentrations (56 to 87%) of linoleic acid occurred in cholesteryl esters for all diets despite low concentrations of linoleic acid in the tallow and coconut oil diets.     

Compositional and textural properties of milkfat–soybean oil blends following enzymatic interesterification

Milkfat–soybean oil blends were enzymatically interesterified (EIE) by Aspergillus niger lipase immobilized on SiO₂–PVA hybrid composite in a solvent free system. An experimental mixture design was used to study the effects of binary blends of milkfat–soybean oil (MF:SBO) at different proportions (0:100; 25:75; 33:67; 50:50; 67:33; 75:25; 100:0) on the compositional and textural properties of the EIE products, considering, as response variables, the interesterification yield (IY), consistency and hardness. Lipase-catalysed interesterification reactions increased the relative proportion of TAGs’ C₄₆–C₅₂ and decreased the TAGs’ C₄₀–C₄₂ and C₅₄ concentrations. The highest IY was attained (10.8%) for EIE blend of MF:SBO 67:33 resulting in a more spreadable material at refrigerator temperature in comparison with butter, milkfat or non-interesterified (NIE) blend. In this case, consistency and hardness values were at least 32% lower than values measured for butter. Thus, using A. niger lipase immobilized on SiO₂–PVA improves the textural properties of milkfat and has potential for development of a product incorporating unsaturated and essential fatty acids from soybean oil.