Enzymatic Interesterification of Vegetable Oil:A Review on Physicochemical and Functional Properties, and Its Health Effects.

In recent years, scientists and technologists have become increasingly interested in producing modified lipids with enhanced nutritional and functional properties. The application and functional properties of fats and oil depend on the composition and structure of triacylglycerols (TAG). As a result, lipid TAG changes can be used to synthesize tailored lipids with a broader range of applications. However, no natural edible oil is available with appropriate dietary and functional properties to meet the human recommended dietary allowances (RDA). On the other hand, the arising health concern is the transfat consumption produced during the chemical modification of vegetable oil through the partial hydrogenation process. Therefore, innovative technologies are shifting toward modifying fat and oil to improve their functionality. Enzymatic interesterification (EIE) is one of the emerging and novel technology to modify the technological traits of naturally available edible oil. It helps in modifying physicochemical, functional, oxidative, and nutritional characteristics of fats and oil due to the rearrangement of the fatty acid positions in the glycerol backbone after interesterification. Enzymatic interesterification utilizes lipase as a biocatalyst with specificity and selectivity to produce desired lipids. Alternation in the molecular structure of triacylglycerol results in changes in melting/dropping point, thermal properties, crystallization behavior, solid fat content, and oxidative stability. Because of its high acyl exchange reaction efficiency, simple reaction process, flexibility, eco-friendly, and generation of fewer by-products, (EIE) is gaining more attention as a substitute lipid modification approach. This review paper discusses the uses of EIE in developing modified fat with desirable physicochemical and nutritional properties. EIE is one of the potential techniques to modify vegetable oil's physicochemical, functional, and nutritional characteristics without producing any undesirable reaction products. EIE produces different modified lipids such as trans fat-free margarine, plastic fat, bakery, confectionery fat, therapeutic oil, infant food, cocoa butter substitute, and equivalent.

Soybean Oil Treatment Using the Dissolving Curve Equation of Hydrogen.

The solubility of hydrogen in n-hexane was determined using a homemade reactor. The solubility of hydrogen in soybean oil was established using the Peng-Robinson (PR) equation of state and the van der Waals mixing rule. The curve equation established a linear relationship between the solubility of hydrogen in oil and the number of moles of hydrogen in the reactor. Under the optimal temperature and catalyst, the relationship between the hydrogen consumption of the hydrogenation of oil and fat and the TFAs formed in the oil was determined. When the reaction pressure exceeded 3.0 MPa, the hydrogenation of oil was consumed. The amount of hydrogen, the rate of hydrogenation, and the change in the TFAs all stabilized. Therefore, the pressure of the general hydrogenation reaction should not exceed 3.0 MPa. This result provides a quick and simple method for controlling TFAs in oils and fats for industrial applications.

[Molecular Mechanisms Underlying Toxic Actions of trans-Fatty Acids and Prevention of Related Diseases].

trans-Fatty acids (TFAs), including elaidic acid and linoelaidic acid, are unsaturated fatty acids that contain one or more carbon-carbon double bonds in trans configuration. TFAs are not synthesized in the human body, but are taken into the body from various foods, which are mainly produced during industrial food manufacturing. Recent epidemiological studies have revealed that TFA consumption is a major risk factor for various disorders, such as atherosclerosis, cardiovascular diseases, allergic diseases, and dementia. However, the underlying pathogenic mechanisms of TFA-related disorders and the specific molecular targets evoking TFA toxicity are largely unknown. To elucidate the molecular mechanisms by which TFAs cause the cytotoxicity, we focused on cell death and inflammation, which are the main and common pathogenesis of the TFA-related diseases, and analyzed the effects of TFAs on cellular responses to various stimulations inducing cell death and inflammation. This review provides recent progress in our studies on the molecular mechanisms causing toxic actions of TFAs, which lead to diverse TFA-related disorders.

Reduction of trans fatty acids in hydrogenated soybean oil using Ni/TiO2 catalysts.

The effects of the support on the catalytic performance of supported Ni catalysts for the hydrogenation of soybean oil were examined. The turnover frequency (TOF) for Ni/TiO2 was greater than those for other Ni catalysts. Among the examined Ni catalysts, the Ni/TiO2 catalysts were effective for the reduction of trans fatty acid (TFA) levels (minimum 10.5%) in hydrogenated oils at an iodine value (IV) of 70, independent of the difference in the crystalline structure of TiO2. In addition, the oils hydrogenated by Ni/TiO2 had suitable properties for feedstock of margarine and vegetable shortening. The highly dispersed Ni nanoparticles formed by reduction of the NiO monolayer on the surface of TiO2 contribute to increasing the catalytic activity and to reducing the TFA levels.

Action of phytosterols on thermally induced trans fatty acids in peanut oil.

The effects of six phytosterols on thermally induced trans fatty acids (TFAs) in peanut oil were investigated. Peanut oil, triolein, trilinolein and trilinolenin heated at 180 °C for 12 and 24 h with or without phytosterols were analyzed by GC-FID. The atomic net charge distribution, frontier molecular orbital energy (FMOE), and bond dissociation energy (BDE) of six phytosterols were calculated by density functional theory. Results showed that six phytosterols inhibited the formation of trans oleic acid, trans linoleic acids, trans linolenic acids, and total TFAs. The anti-isomerization effects of phytosterols were mainly associated with hydroxyl site activities, which were affected by the double bond position in the main skeleton of cyclopentane tetrahydrophenanthrene and the number of double bonds on the C17 branch chain. The FMOE difference and BDE of phytosterol molecules were closely related to their anti-isomerization rates. The anti-isomerization mechanisms of phytosterols on TFAs in peanut oil were proposed.

Red blood cell membrane trans fatty acid levels and risk of non-Hodgkin lymphoma: a prospective nested case-control study.

BACKGROUND: Trans fatty acid (TFA) intake persists in much of the world, posing ongoing threats to public health that warrant further elucidation. Published evidence suggests a positive association of self-reported TFA intake with non-Hodgkin lymphoma (NHL) risk. OBJECTIVES: To confirm those reports, we conducted a prospective study of prediagnosis RBC membrane TFA levels and risk of NHL and common NHL histologic subtypes. METHODS: We conducted a nested case-control study in Nurses' Health Study and Health Professionals Follow-Up Study participants with archived RBC specimens and no history of cancer at blood draw (1989-1090 and 1994-1995, respectively). We confirmed 583 incident NHL cases (332 women and 251 men) and individually matched 583 controls on cohort (sex), age, race, and blood draw date/time. We analyzed RBC membrane TFA using GLC (in 2013-2014) and expressed individual TFA levels as a percentage of total fatty acids. We used unconditional logistic regression adjusted for the matching factors to estimate ORs and 95% CIs for overall NHL risk per 1 SD increase in TFA level and assessed histologic subtype-specific associations with multivariable polytomous logistic regression. RESULTS: Total and individual TFA levels were not associated with risk of all NHL or most subtypes. We observed a positive association of total TFA levels with diffuse large B cell lymphoma (DLBCL) risk [n = 98 cases; OR (95% CI) per 1 SD increase: 1.30 (1.05, 1.61); P = 0.015], driven by trans 18:1n-9(ω-9)/elaidic acid [OR (95% CI): 1.34 (1.08, 1.66); P = 0.007], trans 18:1n-7/vaccenic acid [OR (95% CI): 1.28 (1.04, 1.58); P = 0.023], and trans 18:2n-6t,t [OR (95% CI): 1.26 (1.01, 1.57); P = 0.037]. CONCLUSIONS: Our findings extended evidence for TFA intake and DLBCL risk but not for other NHL subtypes. Reduced TFA consumption through dietary choices or health policy measures may support prevention of DLBCL, an aggressive NHL subtype.

Drinkable lecithin nanovesicles to study the biological effects of individual hydrophobic macronutrients and food preferences.

Fundamental nutritional studies on bioactive molecules require minimizing exposure to confounding foreign elements, like solvents. Herein, aqueous formulations of lecithin nanovesicles are proposed to study three individual trans fatty acids relevant to human nutrition: elaidic acid, trans-vaccenic acid and trans-palmitoleic acid. This proof-of-concept study describes the encapsulation of fatty acids, in vivo bioavailability, and the use of nanovesicles in behavioral experiments. The oral bioavailability of the encapsulated molecules and the selective exposure of animals to each trans-fatty acid of interest were confirmed in healthy rats. Behavioral studies also evidenced that nanovesicles can be used to evaluate the palatability of the lipids and investigate food preferences in mice. Altogether this study shows that lecithin nanovesicles offer an elegant tool to efficiently deliver hydrophobic molecules to animal models. This approach paves the way for future studies deconvoluting the nutritional effects of trans-fatty acids.

Eighteen­carbon trans fatty acids and inflammation in the context of atherosclerosis.

Endothelial dysfunction is a pro-inflammatory state characterized by chronic activation of the endothelium, which leads to atherosclerosis and cardiovascular disease (CVD). Intake of trans fatty acids (TFAs) is associated with an increased risk of CVD. This risk is usually associated with industrial TFAs (iTFAs) rather than ruminant TFAs (rTFAs); however it is not clear how specific TFA isomers differ in their biological activity and mechanisms of action with regard to inflammation. Here we review the literature on 18­carbon TFAs, including the research associating their intake or levels with CVD and studies relating 18­carbon TFA exposure to modulation of inflammatory processes. The evidence associating iTFAs with CVD risk factors is fairly consistent and studies in humans usually show a relation between iTFAs and higher levels of inflammatory markers. In contrast, studies in humans, animals and in vitro suggest that rTFAs have null or mildly beneficial effects in cardiovascular health, metabolic parameters and inflammatory markers, although the evidence is not always consistent. More studies are needed to better identify the beneficial and detrimental effects of the different TFAs, including those with 18 carbons.

Lipid Composition of Brazilian Chocolates and Chocolate Products with Special Emphasis on Their Fat Origin and Trans C18:1 Isomeric Profile.

The aim of this work was to provide recent fatty acid (FA) profiling of chocolates and chocolate products, principally C18:1 trans FAs (TFAs). Thirty-two samples were analyzed by gas chromatography and FAs were quantified. The total TFA content declared in chocolate labeling and the real TFA content were compared. The TFA content ranged from 0.04 to 2.51 g/100 g of sample, and it was noticed that several manufacturers were underestimating the total TFA content in their labeling. The main TFA isomers quantified were C18:1 trans-9 (0.006-0.244%), C18:1 trans-10 (0.009-0.392%), and C18:1 trans-11 (0.013-0.464%), expressed in g/100 g of sample. Principal component analysis was used to discriminate industrial fats from natural trans fats based on the isomeric TFA profile and dairy fat (DF) biomarkers allowing to group samples in four clusters: high TFA content and high DF content, high TFA content and low DF content, low TFA content and high DF content, and low TFA content and low DF content.

Screening method for simultaneous detection of elaidic and vaccenic trans fatty acid isomers by capillary zone electrophoresis.

A novel screening method for the simultaneous detection of elaidic and vaccenic trans fatty acid isomers by CZE-UV was proposed and applied to brazilian spreadable cheese analysis. Optimized background electrolyte was composed by 10 mmol L-1 heptakis (2, 3, 6-tri-o-methyl)-beta cyclodextrin, 24 mmol L-1 sodium tetraborate buffer solution, 45% methanol and 15% acetonitrile. Sample preparation comprised only a saponification reaction and dilution of sample solution before analysis. The method proved to be simple, environmental friendly and sensitive (LOD calculated for elaidic and vaccenic acid were 0.0163 mmol L-1 and 0.0169 mmol L-1, respectively) and may be used to detect adulteration in dairy products, where the addition of hydrogenated vegetable fat to food is prohibited.

Evaluating the Content and Distribution of Trans Fatty Acid Isomers in Foods Consumed in Japan.

Trans fatty acids (TFA) are considered risk factors for cardiovascular disease. However, detailed information on total content of TFA and TFA isomers and distribution of trans-octadecenoic acid positional isomers in foods consumed in Japan is not available till date. In this study, 250 foods, 169 processed foods and 81 foods derived from ruminant meat or milk, were analyzed. According to the results, most foods contained less than 1.0 g TFA / 100 g food. However, almost all foods containing butter had more than 1.0 g TFA / 100 g food. TFA isomers in foods were classified into two categories, monoene-rich type and polyenerich type. We hypothesized that these differences were attributed to diverse TFA formation mechanisms. Furthermore, we observed that trans-10-18:1 was also the dominant trans-18:1 positional isomer in foods consumed in Japan. These results are valuable for future analysis of the role of TFA in epidemiological studies in Japan.

Fabrication of Zein/Pectin Hybrid Particle-Stabilized Pickering High Internal Phase Emulsions with Robust and Ordered Interface Architecture.

Diets containing partially hydrogenated oils (PHOs) expose the human body to trans fatty acids, thus endangering cardiovascular health. Pickering high internal phase emulsions (HIPEs) is a promising alternative of PHOs. This work attempted to construct stable Pickering HIPEs by engineering interface architecture through manipulating the interfacial, self-assembly, and packing behavior of zein particles using the interaction between protein and pectin. Partially wettable zein/pectin hybrid particles (ZPHPs) with three-phase contact angles ranging from 84° to 87° were developed successfully. ZPHPs were irreversibly anchored at the oil-water interface, resulting in robust and ordered interfacial structure, evidenced by the combination of LB-SEM and CLSM. This situation helped to hold a percolating 3D oil droplet network, which facilitated the formation of Pickering HIPEs with viscoelasticity, excellent thixotropy (>91.0%), and storage stability. Curcumin in HIPEs was well protected from UV-induced degradation and endowed HIPEs with ideal oxidant stability. Fabricated Pickering HIPEs possess a charming application prospect in foods and the pharmaceutical industry.

Structural Determination and Occurrence in Ahiflower Oil of Stearidonic Acid Trans Fatty Acids.

Several marine oils and seed oils on the market contain relevant quantities of stearidonic acid (18:4n-3, SDA). The formation of 18:4n-3 trans fatty acids (tFA) during the refining of these oils necessitates the development of a method for their quantification. In this study, 18:4n-3 was isolated from Ahiflower and isomerized to obtain its 16 geometric isomers. The geometric isomers of 18:4n-3 were isolated by silver ion HPLC (Ag+ -HPLC) and characterized by partial reduction with hydrazine followed by gas chromatography analysis. The elution order of all 16 isomers was established using a 100 m × 0.25 mm 100% poly(biscyanopropyl siloxane) capillary column and at the elution temperature of 180 °C. The 4 mono-trans-18:4n-3 isomers produced during the refining of oils rich in 18:4n-3 were chromatographically resolved from each other, but c6,t9,c12,c15-18:4 coeluted with the tetra-cis isomer. These 2 fatty acids (FA) were resolved by reducing the separation temperature to 150 °C, but this change caused tetra-cis-18:4n-3 to coelute with t6,c9,c12,c15-18:4. Combining the results from 2 isothermal separations (180 and 150 °C) was necessary to quantify the 4 mono-trans 18:4n-3 FA in Ahiflower oil.

Comparative Proteomics Analysis Reveals Trans Fatty Acid Isomers Activates Different Pathways in Human Umbilical Vein Endothelial Cell.

Trans fatty acid (TFA), a group of unsaturated fats with at least one double bond in the trans configuration, plays a role in lipid metabolism, the structure of the cell membrane phospholipids, and apoptosis. Previous studies demonstrated that TFA was associated with coronary heart disease, obesity, and insulin resistance. Herein, a quantitative proteomics approach estimated the relative abundance of proteins in human umbilical vein endothelial cells treated with TFA (two different TFA structural isomers: 9t-18:1 and 9t,12t-18:2). The results revealed that 174 identified proteins were significantly altered with respect to expression. Furthermore, based on the cutoff values, 35 proteins were differentially expressed in the 9t-18:1 group as compared to the control group, 69 proteins were differentially expressed in 9t,12t-18:2 group as compared to the control group, and 120 proteins were differentially expressed in the 9t,12t-18:2 group as compared to the 9t-18:1 group. Based on the bioinformatics analysis, we found that TFA could alter the structural constitution of the cytoskeleton through protein interactions, localization into the cell membrane, and incorporation into the phospholipid of the cell. In addition, 17 differential apoptosis-related proteins, including cell division cycle 42, superoxide dismutase 1, glyoxalase I, and macrophage migration inhibitory factor were also identified. Together, these results might emphasize the need for studying TFA-induced biological processes.

Biological effects of trans fatty acids and their possible roles in the lipid rafts in apoptosis regulation.

A large number of recent studies are focused on evaluating the mechanism of action of trans fatty acids (TFAs) on the progression of apoptosis. A strong positive association has been reported between TFA and coronary heart disease (CHD), obesity and nonalcoholic steatohepatitis and so on. The present study reviewed the biological effects of trans fatty acids (TFA) and their possible roles in lipid rafts in regulating apoptosis. The following aspects of TFA were included: the research about TFA and diseases affecting serum lipid levels, inducing system inflammation and immune response, and the correlation between TFA and apoptosis. The primary purpose of the review article was to comprehensively evaluate the potential correlation between lipid rafts and apoptosis induced by different structures of TFA and provide some new research progress and future directions about it.

A low trans margarine fat analog to beef tallow for healthier formulations: Optimization of enzymatic interesterification using soybean oil and fully hydrogenated palm oil.

The health hazard of tallow and partial hydrogenated oils is well known in margarine productions. For this, food manufactures are urged to develop novel alternatives for healthier margarine formulations. The highest interesterification degree acquired with lipase Lipozyme 435 standing out from other catalysts (solid acid, sodium hydroxide and methoxide) was applied to produce low trans margarine fat analogs to beef tallow (BT) with the blend of soybean oil (SO) and fully hydrogenated palm oil (FHPO) in a mass ratio of 4:3. Reaction parameters like enzyme dosage (4.2 wt%), temperature (95 °C) and time (245 min) were optimized using the Box-Behnken design. Regarding fatty acid profiles, triacylglycerol species, solid fat content, polymorphism, melting and crystallization behaviors, the resulting interesterified oil was characterized in comparison with BT, FHPO and the SO-FHPO blend so as to prove its potential in formulating low trans fat margarines because of desirable physicochemical properties and polymorphs.

Preparation of the Pt/CNTs Catalyst and Its Application to the Fabrication of Hydrogenated Soybean Oil Containing a Low Content of Trans Fatty Acids Using the Solid Polymer Electrolyte Reactor.

Pt/CNTs were synthesized with an ethylene glycol reduction method, and the effects of carboxyl functionalization, ultrasonic power and the concentration of chloroplatinic acid on the catalytic activity of Pt/CNTs were investigated. The optimal performance of the Pt/CNTs catalyst was obtained when the ultrasonic power was 300 W and the concentration of chloroplatinic acid was 40 mg/mL. The durability and stability of the Pt/CNTs catalyst were considerably better compared to Pt/C, as shown by cyclic voltammetry measurement results. The trans fatty acids content of the obtained hydrogenated soybean oil (IV: 108.4 gl2/100 g oil) using Pt/CNTs as the cathode catalyst in a solid polymer electrolyte reactor was only 1.49%. The IV of hydrogenated soybean oil obtained using CNTs as carrier with Pt loading 0.1 mg/cm2 (IV: 108.4 gl2/100 g oil) was lower than carbon with a Pt loading of 0.8 mg/cm2 (IV: 109.9 gl2/100 g oil). Thus, to achive the same IV, the usage of Pt was much less when carbon nanotubes were selected as catalyst carrier compared to traditional carbon carrier. The changes of fatty acid components and the hydrogenated selectivity of octadecenoic acid were also discussed.

Study of Trans Fatty Acid Formation in Oil by Heating Using Model Compounds.

The intake of trans fatty acids (TFAs) in foods changes the ratio of low density lipoprotein (LDL) to high density lipoprotein (HDL) cholesterol in blood, which causes cardiovascular disease. TFAs are formed by trans isomerization of unsaturated fatty acids (UFAs). The most recognized formation mechanisms of TFAs are hydrogenation of liquid oil to form partially hydrogenated oil (PHO,) and biohydrogenation of UFAs to form TFA in ruminants. Heating oil also forms TFAs; however, the mechanism of formation, and the TFA isomers formed have not been well investigated. In this study, the trans isomerization mechanism of unsaturated fatty acid formation by heating was examined using the model compounds oleic acid, trioleate, linoleic acid, and trilinoleate for liquid plant oil. The formation of TFAs was found to be suppressed by the addition of an antioxidant and argon gas. Furthermore, the quantity of formed TFAs correlated with the quantity of formed polymer in trioleate heated with air and oxygen. These results suggest that radical reactions form TFAs from UFAs by heating. Furthermore, trans isomerization by heating oleic acid and linoleic acid did not change the original double bond positions. Therefore, the distribution of TFA isomers formed was very simple. In contrast, the mixtures of TFA isomers formed from PHO and ruminant UFAs are complicated because migration of double bonds occurs during hydrogenation and biohydrogenation. These findings suggest that trans isomerization by heating is executed by a completely different mechanism than in hydrogenation and biohydrogenation.

Influence of trans fatty acids on glucose metabolism in soleus muscle of rats fed diets enriched in or deprived of linoleic acid.

PURPOSE: Industrial trans fatty acid (TFA) intake leads to impaired glucose metabolism. However, the overall effects reported are inconsistent and vary with the dietary FA composition and TFA isomer type and levels. We investigated TFA effects on glucose uptake, incorporation and oxidation, and glycogen synthesis in incubated soleus muscle under basal conditions or after treatment with insulin and/or palmitate. METHODS: Male Wistar rats were fed either linoleic acid (LA)-enriched (+LA) or LA-deprived (-LA) diet, supplemented (+LA + TFA or -LA + TFA) or not with TFA, for 60 days. Soleus muscle glucose metabolism was assessed in the absence or presence of insulin and/or palmitic acid. RESULTS: Under basal conditions, TFA enhanced glucose uptake and oxidation regardless of the LA status. Both TFA-supplemented groups had lower insulin response to glucose metabolism. Under insulin-stimulated conditions, TFA prevented the palmitate inhibition of muscle glucose uptake and metabolism in the +LA + TFA group. CONCLUSION: Dietary TFA enhanced glucose utilization in incubated soleus muscle under basal conditions and prevented the palmitate-induced inhibition in insulin-stimulated conditions. However, TFA reduced the insulin response to glucose uptake and metabolism. The effects mentioned above were influenced by the FA profile modifications induced by the dietary LA levels, suggesting that lipid metabolization and incorporation into plasma membrane are important determining factors of glucose metabolism and insulin sensitivity.