Synthesis and characterization of canola oil-stearic acid-based trans-free structured lipids for possible margarine application

Incorporation of stearic acid into canola oil to produce trans-free structured lipid (SL) as a healthy alternative to partially hydrogenated fats for margarine formulation was investigated. Response surface methodology was used to study the effects of lipozyme RM IM from Rhizomucor miehei and Candida rugosa lipase isoform 1 (LIP1) and two acyl donors, stearic acid and ethyl stearate, on the incorporation. Lipozyme RM IM and ethyl stearate gave the best result. Gram quantities of SLs were synthesized using lipozyme RM IM, and the products were compared to SL made by chemical catalysis and fat from commercial margarines. After short-path distillation, the products were characterized by GC and RPHPLC-MS to obtain fatty acid and triacylglycerol profiles, 13C NMR spectrometry for regiospecific analysis, X-ray diffraction for crystal forms, and DSC for melting profile. Stearic acid was incorporated into canola oil, mainly at the sn-1,3 positions, for the lipase reaction, and no new trans fatty acids formed. Most SL products did not have adequate solid fat content or beta' crystal forms for tub margarine, although these may be suitable for light margarine formulation.     

Chemical interesterification of blends of palm stearin, coconut oil, and canola oil: physicochemical properties

trans-Free interesterified fat was produced for possible usage as a margarine. Palm stearin, coconut oil, and canola oil were used as substrates for chemical interesterification. The main aim of the present study was to evaluate the physicochemical properties of blends of palm stearin, coconut oil, and canola oil submitted to chemical interesterification using sodium methoxide as the catalyst. The original and interesterified blends were examined for fatty acid composition, softening and melting points, solid fat content, and consistency. Chemical interesterification reduced softening and melting points, consistency, and solid fat content. The interesterified fats showed desirable physicochemical properties for possible use as a margarine. Therefore, our result suggested that the interesterified fat without trans-fatty acids could be used as an alternative to partially hydrogenated fat.     

Synthesis of structured lipids by transesterification of trilinolein catalyzed by Lipozyme IM60

Structured lipids (SL) containing caprylic, stearic, and linoleic acids were synthesized by enzymatic transesterification using Lipozyme IM60. Pure trilinolein and free fatty acids were used as substrates. Incorporation of stearic acid was higher than that of caprylic acid in all parameters. Highest incorporations of both acids were achieved at 32 h, mole ratio of 1:4:4 (trilinolein/caprylic/stearic acids), water content of 1% (wt %), temperature of 55 degrees C, and 10% (wt %) enzyme load. The maximal incorporations of caprylic and stearic acids were 23.73 and 62.46 mol %, respectively. Reaction time, water content, and enzyme load had major influences on the reaction, whereas substrate mole ratio and temperature showed less influence. Lipozyme showed good stability over six reuses. Differential scanning calorimetric analysis of SL gave a melting profile with a very low melting peak of 0-3.3 degrees C and a solid fat content of 25.21% at 0 degrees C. The melting profile and solid fat content of SL were compared with those of fats extracted from commercially available solid and liquid margarine products. The data suggest that enzymatically produced SL could be used in liquid margarine products.     

Synthesis of structured lipids containing medium-chain and omega-3 fatty acids

The ability of different lipases to incorporate omega3 fatty acids, namely, eicosapentaenoic acid (EPA, C20:5n-3), docosapentaenoic acid (DPA, C22:5n-3), and docosahexaenoic acid (DHA, C22:6n-3), into a high-laurate canola oil, known as Laurical 35, was studied. Lipases from Mucor miehei (Lipozyme-IM), Pseudomonas sp. (PS-30), and Candida rugosa (AY-30) catalyzed optimum incorporation of EPA, DPA, and DHA into Laurical 35, respectively. Other lipases used were Candida anatrctica (Novozyme-435) and Aspergillus niger (AP-12). Response surface methodology (RSM) was used to obtain a maximum incorporation of EPA, DPA, and DHA into high-laurate canola oil. The process variables studied were the amount of enzyme (2-6%), reaction temperature (35-55 degrees C), and incubation time (12-36 h). The amount of water added and mole ratio of substrates (oil to n-3 fatty acids) were kept at 2% and 1:3, respectively. The maximum incorporation of EPA (62.2%) into Laurical 35 was predicted at 4.36% of enzyme load and 43.2 degrees C over 23.9 h. Under optimum conditions (5.41% enzyme; 38.7 degrees C; 33.5 h), the incorporation of DPA into high-laurate canola oil was 50.8%. The corresponding maximum incorporation of DHA (34.1%) into Laurical 35 was obtained using 5.25% enzyme, at 43.7 degrees C, over 44.7 h. Thus, the number of double bonds and the chain length of fatty acids had a marked effect on the incorporation omega3 fatty acids into Laurical 35. EPA and DHA were mainly esterified to the sn-1,3 positions of the modified oils, whereas DPA was randomly distributed over the three positions of the triacylglycerol molecules. Meanwhile, lauric acid remained esterified mainly to the sn-1 and sn-3 positions of the modified oils. Enzymatically modified Laurical 35 with EPA, DPA, or DHA had higher conjugated diene (CD) and thiobarbituric acid reactive substance (TBARS) values than their unmodified counterpart. Thus, enzymatically modified oils were more susceptible to oxidation than their unmodified counterparts, when both CD and TBARS values were considered.     

Optimization of solid fat content and crystal properties of a trans-free structured lipid by blending with palm midfraction

The optimization of solid fat content (SFC) and crystal properties of trans-free structured lipids (SL) synthesized by incorporating stearic acid into canola oil was investigated. The SLs were blended with varying amounts of palm midfraction (PMF). The SFC and crystal polymorphism were improved. The addition of sucrose stearate (S-170), sorbitan tristearate (STS), and distilled monoglycerides (DMG) to one of the blends, SL40:PMF (70:30, w/w), did not improve crystal polymorphism but had significant effects on crystal morphology. The emulsifiers significantly delayed crystal growth, resulting in smaller crystal sizes as compared to the control. They were unable to inhibit the formation of granular crystals (30-140 microm), which are undesirable in margarine, after 4 weeks of storage at 0 degrees C. Blends treated with S-170 and STS showed many small evenly distributed crystals interspersed with large crystal aggregates (after 4 weeks of storage), whereas the blend treated with DMG and the control showed irregularly shaped globular crystals, also interspersed with large crystal aggregates. However, these crystal aggregates were not observed upon visual and physical examination and may therefore not impart the sensory properties of the finished products negatively.     

Esterified propoxylated glycerol soyate, a fat substitute model compound, and soy oil after heating.

The changes occurring in two oil samples [EPG-00 soyate (transesterified soybean oil) and soy oil esterified propoxylated glycerol (EPG-08 soyate, a model, fat substitute compound)] were compared after heating at approximately 190 degrees C for 12 h/day. The EPG-00 soyate sample required 48 h of heating to attain a polymer content >20%, while the EPG-08 soyate required only 36 h. After 48 h of heating the EPG-00 soyate sample, the free fatty acid value (FFA) increased from 0.19 to 0.79, the acid value (AV) increased from 0.10 to 1.59, and the p-anisidine value (p-AV) increased from 1.6 to 195.4. In comparison, after only 36 h of heating, the EPG-08 soyate sample had FFA, AV, and p-AV increases from 0.19 to 0.71, from 0.26 to 1.36, and from 1.1 to 191.7, respectively. The triacylglycerol substrate degradation rate for EPG-00 soyate was k = 0.0126 +/- 0.0003 h(-)(1), while the rate for EPG-08 soyate was k = 0.0166 +/- 0.0017 h(-)(1). The results suggest that the EPG-00 soyate or transesterified soybean oil is slightly more stable than EPG-08 soyate.     

Chemical and physical properties of butterfat-vegetable oil blend spread prepared with enzymatically transesterified canola oil and caprylic acid

Structured Lipid was synthesized from canola oil and caprylic acid with sn-1,3 specific lipase from Rhizomucor miehei. Cold spreadable butter was made by blending butterfat with the SL at a weight ratio of 80:20. Its chemical and physical properties were compared with pure butter and butterfat-canola oil 80:20 blend spread. The butterfat-SL blend had lower contents of hypercholesterolemic fatty acids (FAs) and the lowest atherogenic index (AI) as compared to the others. Melting and crystallization behaviors of butterfat-SL blend were similar to those of butterfat-canola oil blend above 0 degrees C. It showed solid fat contents (SFCs) similar to butterfat-canola oil blend but lower than pure butterfat. The butterfat-SL blend was shown to crystallize in the beta' form. There were no differences between the hardness of butterfat-SL blend spread and butterfat-canola oil blend spread. Rheological analysis showed that butterfat-SL blend spread lost its elastic behavior at 5 degrees C, a lower temperature than pure butter.     

Characteristics of structured lipid prepared by lipase-catalyzed acidolysis of roasted sesame oil and caprylic acid in a bench-scale continuous packed bed reactor

Structured lipid (SL) was prepared from roasted sesame oil and caprylic acid (CA) by Rhizomucor miehei lipase-catalyzed acidolysis in a bench-scale continuous packed bed reactor. Total incorporation and acyl migration of CA in the SL were 42.5 and 3.1 mol %, respectively, and the half-life of the lipase was 19.2 days. The SL displayed different physical and chemical properties, less saturated dark brown color, lower viscosity, lower melting and crystallization temperature ranges, higher melting and crystallization enthalpies, higher smoke point, higher saponification value, and lower iodine value, in comparison to those of unmodified sesame oil. The oxidative stability of purified SL was lower than that of sesame oil. There were no differences in the contents of unsaponifiables including tocopherols and phytosterols. However, total sesame lignans content was decreased in SL due to the loss of sesamol when compared to sesame oil. Most of the 70 volatiles present in roasted sesame oil were removed from SL during short-path distillation of SL. These results indicate that the characteristics of SL are different from those of original sesame oil in several aspects except for the contents of tocopherols and phytosterols.     

trans-Free margarines prepared with canola oil/palm stearin/palm kernel oil-based structured lipids

Structured lipids (SLs) for formulating trans-free margarines were synthesized by lipase-catalyzed interesterification of the blends of canola oil (CO), palm stearin (PS), and palm kernel oil (PKO) in weight ratios (CO/PS/PKO) of 40:60:0, 40:50:10, 40:40:20, 40:30:30, 50:30:20, and 60:25:15. The atherogenicity was determined using fatty acid profiles. We also determined the physical properties (melting/crystallization profiles, solid fat content, polymorphism, and microstructure) of SLs and the textural properties of margarines made with the SLs. The SLs from the 50:30:20 and 60:25:15 blends had atherogenic indices similar to or lower than those of the commercial trans (CTMF) and similar to the trans-free margarine fats (CTFMF). SLs from the blends with PKO contained a wide range of fatty acids (C6-C20) and had more beta' than beta polymorphs. Margarines made with SLs from 50:30:20 and 60:25:15 blends possessed similar hardness, adhesiveness, or cohesiveness to margarines made with CTMF and CTFMF, respectively. Therefore, CO/PS/PKO-based SLs were suitable for formulating trans-free margarines with low atherogenicity and desirable textural properties.     

Production of human milk fat analogue containing docosahexaenoic and arachidonic acids

Human milk fat (HMF) analogue containing docosahexaenoic acid (DHA) and arachidonic acid (ARA) at sn-1,3 positions and palmitic acid (PA) at sn-2 position was produced. Novozym 435 lipase was used to produce palmitic acid-enriched hazelnut oil (EHO). EHO was then used to produce the final structured lipid (SL) through interesterification reactions using Lipozyme RM IM. Reaction variables for 3 h reactions were temperature, substrate mole ratio, and ARASCO/DHASCO (A:D) ratio. After statistical analysis of DHA, ARA, total PA, and PA content at sn-2 position, a large-scale production was performed at 60 °C, 3:2 A:D ratio, and 1:0.1 substrate mole ratio. For the SL, those results were determined as 57.3 ± 0.4%, 2.7 ± 0.0%, 2.4 ± 0.1%, and 66.1 ± 2.2%, respectively. Tocopherol contents were 84, 19, 85, and 23 μg/g oil for α-, β-, γ-, and δ-tocopherol. Melting range of SL was narrower than that of EHO. Oxidative stability index (OSI) value of SL (0.80 h) was similar to that of EHO (0.88 h). This SL can be used in infant formulas to provide the benefits of ARA and DHA.     

Boron nutrition for improving the quality of diverse canola cultivars

Abstract

Canola (Brassica napus L.), is the most important oilseed crop due to high oil contents and low concentration of erucic acid and glucosinolates. In Pakistan, oil seed production is not sufficient to fulfill the needs of the country. Thus, the planned experiment was aimed to evaluate the performance of different canola cultivars i.e. Faisal Canola, Pakola, PARC Canola hybrid and Rainbow at grown under various soil applied boron (B) levels viz., 0, 1, 2?kg ha^?1 under a rainfed environment. The experiment was laid out in randomized complete block design with four replications. Among the canola cultivars, the maximum seed oil contents were recorded in cultivar ‘Pakola’ whereas, higher linolenic acid and protein were recorded in cultivar ‘Faisal canola’ as compared to other cultivars. A synergistic effect was found between various levels of B and quality parameters of the canola seed; as higher concentration of oil contents were found when B was applied 2?kg ha^?1. Conversely the linolenic acid showed the antagonistic behavior with the various B levels. On the other hand, protein contents, oleic acid and erucic acid revealed non-significant differences under different B application rates. In conclusion, the cultivar ‘Pakola’ provided the highest oil content when the B was applied at 2?kg ha^?1; the low concentration of unsaturated fatty acid was observed in ‘PARC canola’ cultivar in the Pothwar region of Punjab, Pakistan.     

Antiatherogenic effects of structured lipid containing conjugated linoleic acid in C57BL/6J mice

Conjugated linoleic acids (CLA) were enzymatically acidolyzed with olive oil to produce structured lipids (SL), and their antiatherosclerotic properties were investigated in C57BL/6J mice. Twenty-eight mice were divided into four groups and fed control diet or atherogenic diets supplemented with high cholesterol and high fat (HCHF) containing 5% of lard, olive oil, or SL based on control diet for 4 weeks. The supplementation of SL diet (0.6% CLA) significantly reduced the levels of serum total cholesterol and total triglyceride and increased high-density lipoprotein cholesterol level as compared to lard and olive oil diet groups (p < 0.05). The activity of liver acyl CoA:cholesterol acyltransferase (ACAT) of mice fed the SL diet was significantly lower than that of mice fed the lard or olive oil diet. A reduced formation of aortic fatty streak was observed in SL group. The extent of CLA incorporation depended on tissues or types of phospholipids. More CLA was incorporated in adipose tissue (1.85 mol %) than in the liver (0.33 mol %). Besides, more CLA was found in phosphatidylethanolamine (PE) (0.47 mol %) than in phosphatidylcholine (PC) (0.05 mol %) of hepatic phospholipids. Hepatic phospholipids (PC and PE) of mice fed the SL diet contained reduced contents of arachidonic and linoleic acid compared with mice fed the olive oil or lard diet. The present study suggests that SL could be considered as a functional oil for preventing risks of atheroscelerosis.     

Preparation of spread oils meeting U.S. Food and Drug Administration Labeling requirements for trans fatty acids via pressure-controlled hydrogenation

On July 11, 2003, the U.S. Food and Drug Administration (FDA) announced final regulations for trans fatty acid (TFA) labeling. By January 1, 2006, the TFA content of foods must be labeled as a separate line on the Nutrition Facts label. Products containing <0.5 g of TFA/14 g serving may be declared as zero. This paper describes technologies allowing compliance with TFA labeling requirements. Soybean oil was hydrogenated in a 2-L vessel at temperatures ranging from 120 to 170 degrees C at a hydrogen pressure of 200 psi. A commercial nickel-supported catalyst (25% Ni) was used at 0.02% Ni by weight of oil. The hydrogenated oils were characterized for fatty acid composition, solid fat content, and melting point. Compared to commercially processed soybean oil basestocks that typically contain approximately 40% TFA, those obtained at lower temperatures and higher pressures contain >56% less TFA. Basestocks prepared in the laboratory when blended with liquid soybean oil will yield spread oils meeting FDA labeling requirements for zero TFA, that is, <0.5 g of TFA/serving.     

Antioxidant evaluation and oxidative stability of structured lipids from extravirgin olive oil and conjugated linoleic acid

Structured lipid (SL) was synthesized from extravirgin olive oil (EVOO) and conjugated linoleic acid (CLA) via a lipase-catalyzed reaction. CLA provides a variety of health benefits, but it is not consumed in free fatty acid form. The synthesized SL olive oil contained 42.5 mol % CLA isomers, and the major isomers were cis-9,trans-11-CLA (16.9 mol %) and trans-10,cis-12-CLA (24.2 mol %). The antioxidant activity determined by the radical scavenging capacity with the 2,2-diphenyl-1-picrylhydrazyl radical was lower in SL olive oil than in EVOO. The oxidative stability was also lower in SL olive oil since it had a higher peroxide value, rho-anisidine value, and 2-thiobarbituric acid reactive substances values during 20 days of storage at 60 degrees C. This observation could be due to the reduction in the natural phenolic compounds (97%) and tocopherols (56%), and the incorporated CLA with two conjugated double bonds in the SL olive oil. The oxidative stability of SL olive oil was increased by added rosemary extracts at concentrations of 100, 200, and 300 ppm. The present study suggests that the SL olive oil may be a suitable way to incorporate or deliver CLA into human diets. However, the addition of a proper antioxidant would be required for improving its oxidative stability.     

Effect of nitrogen fertilizer on the concentrations of oil and protein in canola (brassica napus) seed

The oil and protein concentration response of canola (Brassica napus L.) to application of nitrogen (N), applied as urea (46%), was measured in 210 field plots done in 1994 and 1995 in south‐western Australia (WA). The canola was grown on a range of soil types deficient in N for maximum seed production. The sites were sown in late May to early June. The concentration of oil in the canola seed decreased concomitantly with an increase in protein. In all experiments, in both years, there was no relationship between the seed yield and the resultant oil or protein concentration. The addition of the oil plus protein concentration in the canola seed was an approximately constant 62% in the both years.     

Effects of alpha-tocopherol, beta-carotene, and soy isoflavones on lipid oxidation of structured lipid-based emulsions

Structured lipids (SLs) are triacylglycerols that have been modified to change the fatty acid composition and/or positional distribution in the glycerol backbone by chemically and/or enzymatically catalyzed reactions and/or genetic engineering. Ten percent oil-in-water emulsions were formulated with a canola oil/caprylic acid SL and stabilized with 0.5% whey protein isolate (WPI) or sucrose fatty acid ester (SFE). The effects of alpha-tocopherol, beta-carotene, genistein, and daidzein (added at 0.02 wt % of oil) on lipid oxidation were evaluated over a 15-day period in emulsion samples. Significantly (p < 0.05) less total oxidation (calculated from peroxide value and anisidine value measurements) occurred in the WPI emulsions compared to their SFE counterparts. In this study, alpha-tocopherol, beta-carotene, and both soy isoflavones exhibited prooxidant activities in SFE emulsions. Because of their ability to exhibit prooxidant activity under certain conditions, manufacturers must experiment with these compounds before adding them to SL-based products as functional ingredients.     

Effect of potassium sulfate on quantitative and qualitative characteristics of canola cultivars upon late-season drought stress conditions

In order to reduce the damage caused by late-season drought stress of canola, a factorial split plot experiment was performed on the basis of the randomized complete blocks design with three replications in Karaj, Iran. The treatments were potassium sulfate in two levels, including application and non-application of potassium sulfate, irrigation at three levels including normal irrigation (control), restricted irrigation from the flowering and pod formation stage, as factorial were in main plots and winter canola cultivars including Opera, L72, KR1, GKH3705, GKH0224 were in subplots. The interaction effect of potassium sulfate?×?irrigation?×?cultivar on seed yield, stomatal resistance, oil yield, linoleic acid, linolenic acid and glucosinolate was significant at the 1% level. The promising line of L72 in normal irrigation and application of potassium sulfate and Opera cultivar under late-season drought stress and application of potassium sulfate had the highest seed yield, oil yield and fatty acids composition.     

Characterization of stearidonic acid soybean oil enriched with palmitic acid produced by solvent-free enzymatic interesterification

Stearidonic acid soybean oil (SDASO) is a plant source of n-3 polyunsaturated fatty acids (n-3 PUFAs). Solvent-free enzymatic interesterification was used to produce structured lipids (SLs) in a 1 L stir-batch reactor with a 1:2 substrate mole ratio of SDASO to tripalmitin, at 65 °C for 18 h. Two SLs were synthesized using immobilized lipases, Novozym 435 and Lipozyme TL IM. Free fatty acids (FFAs) were removed by short-path distillation. SLs were characterized by analyzing FFA and FA (total and positional) contents, iodine and saponification values, melting and crystallization profiles, tocopherols, and oxidative stability. The SLs contained 8.15 and 8.38% total stearidonic acid and 60.84 and 60.63% palmitic acid at the sn-2 position for Novozym 435 SL and Lipozyme TL IM SL, respectively. The SLs were less oxidatively stable than SDASO due to a decrease in tocopherol content after purification of the SLs. The saponification values of the SLs were slightly higher than that of the SDASO. The melting profiles of the SLs were similar, but crystallization profiles differed. The triacylglycerol (TAG) molecular species of the SLs were similar to each other, with tripalmitin being the major TAG. SDASO's major TAG species comprised stearidonic and oleic acids or stearidonic, α-linolenic, and γ-linolenic acids.     

Effect of long-term dietary supplementation of high-gamma-linolenic canola oil versus borage oil on growth, hematology, serum biochemistry, and N-6 fatty acid metabolism in rats

Dietary supplementation of a high-gamma-linolenic acid canola oil (HGCO) containing approximately 36% (w/w) of gamma-linolenic acid (GLA, 18:3n-6) from the seeds of a genetically transformed canola strain, was assessed for its long-term biological effects. Growing Sprague-Dawley rats (n = 30) were fed a purified AIN93G diet containing 5, 10, or 15% (w/w) of HGCO as the fat source. For comparison, a separate group of rats (n = 10) was given the diet containing 15% (w/w) of borage oil (BO), which contained 22% (w/w) of GLA. After 12 weeks of feeding, the growth, relative organ weights, hematology, and serum biochemistry were found to be similar among rats fed the 5, 10, and 15% HGCO diets. The GLA levels in plasma and liver phospholipids (PL) were also similar. However, the levels of GLA in peripheral tissues (muscle PL and adipose triacylglycerols) were significantly higher in rats fed the 10 and 15% HGCO diets than those fed the 5% HGCO diet. When the above biologic parameters were compared between the 15% HGCO and 15% BO dietary groups, there were no significant differences except for lower final body weights and higher tissue levels of GLA, dihomo-gamma-linolenic acid (20:3n-6) and arachidonic acid (20:4n-6) in the 15% HGCO dietary group as compared with the 15% BO dietary group. This is due to a higher GLA content and possibly a more favorable stereospecific distribution of GLA in HGCO. Overall, long-term (12-week) feeding with diets containing up to 15% HGCO resulted in no adverse effects on growth, organ weight, hematology and serum biochemistry as compared to the diet containing 15% BO, suggesting that HGCO may be a safe alternative source of GLA.     

Antioxidant activity of capsaicinoid in canola oil

Interest in replacing synthetic antioxidants, namely, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), with natural antioxidants is increasing. The present study examined the antioxidant activity of capsaicinoid from chili pepper in heated canola oil. The oxidation was conducted at 60, 90, 120, and 180 °C by monitoring oxygen consumption and the decrease in linoleic acid and α-linolenic acid in canola oil. At 60 °C, capsaicinoid was more effective against oxidation of canola oil compared with BHT. At higher temperatures of 90, 120, and 180 °C, capsaicinoid possessed an antioxidant activity similar to or slightly weaker that that of BHT. It was found that capsaicinoid prevented canola oil from oxidation in a dose-dependent manner. To study the structure-antioxidant relationship, it was found that the trimethylsiloxy (TMS) derivatives of capsaicinoid did not exhibit any antioxidant activity, suggesting the hydroxyl moiety was the functional group responsible for the antioxidant activity of capsaicinoid. It was concluded that capsaicinoid had the potential to be further explored as a natural antioxidant in foods, particularly spicy foods.