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.

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.

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.

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.

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.

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.

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.

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.

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.

Effect of Fatty Acid Chain Length on the Crystallization Behavior of Trans-free Margarine Basestocks during Storage.

In order to obtain margarine free of trans-fatty acids, four interesterified basestocks were prepared by chemical interesterification (CIE) of oil blends. Different ratios of palm stearin, palm olein and soybean oil were mixed without and with 1) fully hydrogenated Acer truncatum oil (FHATO), 2) fully hydrogenated rapeseed oil or 3) palm kernel oil containing a similar amount of saturated, monounsaturated and polyunsaturated fatty acids, but different saturated fatty acid length for CIE. Compared to the physical blends, the CIE samples demonstrated lower slip melting points and decreased solid fat contents, especially at high temperatures, indicating that the CIE samples might have improved mouthfeel. In all CIE samples, the ß crystal form disappeared and only the ß' crystal form was observed, except for sample 2, which contained a mixed ß and ß' forms. Furthermore, in all CIE samples, except sample 1, the ß' crystal forms began transforming to ß form after only two cycles of higher temperature treatments indicating that the CIE sample with FHATO had the most resistance to temperature fluctuation during storage which may be attributed to its longer saturated chains. In conclusion, the CIE basestocks containing longer saturated fatty acids could be more suitable for margarine use.

Nutrigenomic point of view on effects and mechanisms of action of ruminant trans fatty acids on insulin resistance and type 2 diabetes.

Evidence from observational studies suggests beneficial effects of ruminant trans fatty acids (rTFA) on insulin resistance (IR) and type 2 diabetes (T2D). However, beneficial effects of rTFA are not always observed in cell, animal, and human studies. This narrative review presents potential mechanisms of action of rTFA using nutrigenomics and microRNA results in an integrative model. In addition, the review presents factors, including measures of IR and T2D, dose and duration of studies, as well as health status, ethnicity, and genotypes of subjects, that may help explain the heterogeneity in response to rTFA supplementation. Future studies should consider these factors, as well as research in nutritional genomics, to better understand the effects of rTFA on IR and T2D.

A prospective study of erythrocyte polyunsaturated fatty acid, weight gain, and risk of becoming overweight or obese in middle-aged and older women.

PURPOSE: ω3 and ω6 fatty acids (FA) may have divergent effects on the development of obesity. We examined the association of baseline erythrocyte ω3 and ω6 FA composition with body weight change and the risk of becoming overweight or obese in the Women's Health Study (WHS) participants. METHODS: We identified 534 women who had baseline erythrocyte FA measured and a baseline body mass index (BMI) of 18.5-<25 kg/m(2). Body weight was updated at a total of six time points during follow-up. RESULTS: Weight gain during a mean of 10.4-year follow-up increased with increasing quartiles of baseline erythrocyte cis ω6 FA, ω6/ω3 ratio, and trans FA while decreased with increasing cis ω3 FA. After multivariable adjustment including total energy intake and physical activity, the weight gain (kg) in the highest versus the lowest quartile was 3.08 versus 2.32 for erythrocyte cis ω6 FA (p trend 0.04), 2.07 versus 2.92 for cis ω3 FA (p trend 0.08), 2.93 versus 2.05 for ω6/ω3 ratio (p trend 0.046), and 3.03 versus 2.27 for trans FA (p trend 0.06). Among individual FA, the associations were significant for 18:2ω6, 18:3ω6, and trans 18:1 and marginally significant for 20:3ω6 and trans 18:2. The risk of becoming overweight or obese (defined as BMI ≥25 kg/m(2) at any follow-up time point) increased across increasing ω6/ω3 ratio (multivariable model p trend 0.04). CONCLUSIONS: In this prospective study, we found suggestive evidence that erythrocyte cis ω6 FA may be positively associated, and cis ω3 FA inversely associated with weight gain in initially normal-weight women.

Double Bond Position Plays an Important Role in Delta-9 Desaturation and Lipogenic Properties of Trans 18:1 Isomers in Mouse Adipocytes.

The objective of this research was to study the delta-9 desaturation of individual trans (t) fatty acids that can be found in ruminant fat or partially hydrogenated vegetable oils (PHVO) and determine their effects on lipogenic gene expression in adipocytes. It was hypothesized that delta-9 desaturation and lipogenic properties of t-18:1 isomers depend on the position of double bond. Differentiated 3T3-L1 adipocytes were treated with 200 µM of t6-18:1, t9-18:1, t11-18:1, t13-18:1 or t16-18:1, cis (c)-9 18:1 or bovine serum albumin (BSA) vehicle control for 48 h. Cells were then harvested for fatty acid and gene expression analyses using gas chromatography and quantitative PCR respectively. Among t-18:1 isomers, t13-18:1 and t11-8:1 had the greatest percent delta-9 desaturation (44 and 41 % respectively) followed by t16-18:1 and t6-18:1 (32 and 17 % respectively), while c9-18:1 and t9-18:1 did not undergo delta-9 desaturation. Trans9-18:1 up-regulated (P < 0.05) the expression of lipogenic genes including fatty acid synthase and stearoyl-CoA desaturase-1 (P < 0.05), whereas the expression of these genes were not affected with other t-18:1 isomers (P > 0.05). Consistent with gene expression results, t9-18:1 increased the de novo lipogenic index (16:0/18:2n-6) compared with control cells and increased delta-9 desaturation index (c9-16:1/18:0) compared to other t-18:1 isomers (P < 0.05). The current study provides further evidence that the predominant trans fatty acid in PHVO (t9-18:1) has isomer specific lipogenic properties.

Regiospecific Distribution of trans-Octadecenoic Acid Positional Isomers in Triacylglycerols of Partially Hydrogenated Vegetable Oil and Ruminant Fat.

It is revealed that binding position of fatty acid in triacylglycerol (TAG) deeply relates to the expression of its function. Therefore, we investigated the binding positions of individual trans-octadecenoic acid (trans-C18:1) positional isomers, known as unhealthy fatty acids, on TAG in partially hydrogenated canola oil (PHCO), milk fat (MF), and beef tallow (BT). The analysis was carried out by the sn-1(3)-selective transesterification of Candida antarctica Lipase B and by using a highly polar ionic liquid capillary column for gas chromatography-flame ionization detection. Trans-9-C18:1, the major trans-C18:1 positional isomer, was selectively located at the sn-2 position of TAG in PHCO, although considerable amounts of trans-9-C18:1 were also esterified at the sn-1(3) position. Meanwhile, trans-11-C18:1, the major isomer in MF and BT, was preferentially located at the sn-1(3) position. These results revealed that the binding position of trans-C18:1 positional isomer varies between various fats and oils.

Effect of extruding full-fat soy flakes on trans fat content.

To evaluate the effects of extrusion process on the trans fatty acids (TFAs) formation in soybean crude oils, three different extrusion parameters, namely, extrusion temperature (80-160 °C), feed moisture (10-26%), and screw speed (100-500 rpm), were carried out. It was found that only five different types of TFAs were detected out using gas chromatography-mass spectrometry. Before the extrusion started, the initial amount of total TFAs was 3.04 g/100 g. However, after extruding under every level of any variable, the total amounts of TFAs were significantly higher than those in the control sample (P < 0.05). For example, taking the effect of extrusion temperature into account, we can find that the highest amount of total of trans fatty acid (TTFA) was 1.62 times the amount of that in the control sample, whereas the lowest amount of TTFA was 1.54 times the amount of that in the control sample. Importantly, it was observed that the amounts of every type of trans fatty acid were not continuously increasing with the increase of the level of any extrusion variable. This phenomenon demonstrated that the formation and diversification were intricate during extruding process and need to be further studied.

Effects of incremental amounts of fish oil on trans fatty acids and Butyrivibrio bacteria in continuous culture fermenters.

Previous studies have shown that adding fish oil (FO) to ruminant animal diets increased vaccenic acid (VA; t11 C18:1) accumulation in the rumen. Therefore, the objective of this study was to evaluate the effect of dietary FO amounts on selected strains of rumen bacteria involved in biohydrogenation. A single-flow continuous culture system consisting of four fermenters was used in a 4 × 4 Latin square design with four 9 days consecutive periods. Treatment diets were as follows: (i) control diet (53:47 forage to concentrate; CON), (ii) control plus FO at 0.5% (DM basis; FOL), (iii) control plus FO at 2% (DM basis; FOM) and (iv) control plus FO at 3.5% (DM basis; FOH). Fermenters were fed treatment diets three times daily at 120 g/day. Samples were collected from each fermenter on day 9 of each period at 1.5, 3 and 6 h post-morning feeding and then composited into one sample per fermenter. Increasing dietary FO amounts resulted in a linear decrease in acetate and isobutyrate concentrations and a linear decrease in acetate-to-propionate ratio. Propionate, butyrate, valerate and isovalerate concentrations were not affected by FO supplementation. Concentrations of C18:0 in fermenters linearly decreased, while concentrations of t10 C18:1 and VA linearly increased as dietary FO amounts increased. The concentrations of c9t11 and t10c12 conjugated linoleic acid were not affected by FO supplementation. The DNA abundance for Butyrivibrio fibrisolvens, Butyrivibrio vaccenic acid subgroup, Butyrivibrio stearic acid subgroup and Butyrivibrio proteoclasticus linearly decreased as dietary FO amounts increased. In conclusion, FO effects on trans fatty acid accumulation in the rumen may be explained in part by FO influence on Butyrivibrio group.

Enzymatic production of trans fatty acid free fat from partially hydrogenated soybean oil (PHSO)--theory, strategy and practicability.

Development of an advanced process/production technology for healthful fats constitutes a major interest of plant oil refinery industry. In this work, a strategy to produce trans fatty acid (TFA) free (or low TFA) products from partially hydrogenated soybean oil by lipase-catalysed selective hydrolysis was proposed, where a physically founded mathematic model to delineate the multi-responses of the reaction as a function of selectivity factor was defined for the first time. The practicability of this strategy was assessed with commercial trans-selective Candida antarctica lipase A (CAL-A) as a model biocatalyst based on a parameter study and fitting to the model. CAL-A was found to have a selectivity factor 4.26 and to maximally remove 73.3% of total TFAs at 46.5% hydrolysis degree.

Enzymatic production of zero-trans plastic fat rich in α-linolenic acid and medium-chain fatty acids from highly hydrogenated soybean oil, Cinnamomum camphora seed oil, and perilla oil by lipozyme TL IM.

In the present study, zero-trans α-linolenic acid (ALA) and medium-chain fatty acids (MCFA)-enriched plastic fats were synthesized through enzymatic interesterification reactions from highly hydrogenated soybean oil (HSO), Cinnamomum camphora seed oil (CCSO), and perilla oil (PO). The reactions were performed by incubating the blending mixtures of HSO, CCSO, and PO at different weight ratios (60:40:100, 70:30:100, 80:20:100) using 10% (total weight of substrate) of Lipozyme TL IM at 65 °C for 8 h. After reaction, the physical properties (fatty acids profile, TAG composition, solid fat content, slip melting point, contents of tocopherol, polymorphic forms, and microstructures) of the interesterified products and their physical blends were determined, respectively. Results showed that the fatty acid compositions of the interesterified products and physical blends had no significant changes, while the content of MCFA in both interesterified products and physical blends increased to 8.58-18.72%. Several new types of TAG species were observed in interesterified products (SSL/SLS, PLO/LLS, and OLLn/LnLO/LOLn). It should be mentioned that no trans fatty acids (TFA) were detected in all products. As the temperature increased, the solid fat content (SFC) of interesterified products was obviously lower than that of physical blends. The SFCs of interesterified products (60:40:100, 70:30:100, and 80:20:100, HSO:CCSO:PO) at 25 °C were 6.5%, 14.6%, and 16.5%, respectively, whereas the counterparts of physical blends were 32.5%, 38.5%, and 43.5%, respectively. Meanwhile, interesterified products showed more ß' polymorphs than physical blends, in which ß' polymorph is a favorite form for production of margarine and shortening. Such zero-trans ALA and MCFA-enriched fats may have desirable physical and nutritional properties for shortenings and margarines.