Monounsaturated Triacylglycerols Research Articles

Development of symmetric monounsaturated triacylglycerols by Rhodosporidium toruloides cell factory for cocoa butter equivalent

AbstractIn the present study, various factors including carbon source, nitrogen source, Mg2+, and pH value were investigated to determine the optimal conditions for producing cocoa butter equivalent using R. toruloides. The maximum of biomass, lipid content, and lipid production were achieved at levels of 7.8 g/L, 61.0%, and 4.4 g/L, respectively. The oil from R. toruloides mainly consisted of 16:0, 18:0, and 18:1 with 18:1 dominating at the sn‐2 position, which was further confirmed by 13C NMR analysis. UPLC‐MS analysis showed that the sum of sn‐POP, sn‐POS, and sn‐SOS accounted for up to 27.11% in the triacylglycerol species of the oil produced, which allows those triacylglycerols to be further separated and isolated from other triacylglycerols and used for cocoa butter equivalent. Notably, the production of cocoa butter equivalent reached 1.13 g/L, demonstrating the scientific feasibility of producing CBE through fermentation. These findings indicate a promising future for the fermentation‐based production of cocoa butter equivalent.

Characterization of the physicochemical properties of mango ( Mangifera indica L., Dragon variety) kernel fat extracted via supercritical carbon dioxide and Soxhlet techniques

Mango kernel fat (MKF) that is high in monounsaturated triacylglycerols is a potential cocoa butter alternative. This study aimed to investigate the yield and physicochemical properties of Dragon variety (Mangifera indica L.) MKF is extracted by supercritical carbon dioxide and Soxhlet. The fatty acid constituent, triacylglycerol constituent, melting and crystallization behavior, and solid fat content (SFC) were analyzed using gas chromatography, high-pressure liquid chromatography, and differential scanning calorimetry, respectively. The yield was 6.59%–9.65% depending on temperature, pressure, and time. Physicochemical properties for both techniques were comparable. The MKF contained higher levels of stearic acid (primarily StOSt, 1,3-distearoyl-2-oleoyl-glycerol) with extraction conditions of 72°C, 30 MPa, and 3 h. Melting and crystallization peaks ranged from 9.84 to 39.13°C and 16.69 to −11.23°C, respectively. SFC was zero between 40 and 45°C. The high StOSt content can aid in fractionation and demonstrates potential in making heat-resistant fat for use in confectioneries. Novelty impact statement The current study investigated the effect of different extraction techniques and conditions on the percentages of fat yield of the Dragon variety mango kernel (Mangifera indica L.), a by-product of the fruit industry, which has not been previously studied. The highest percentage of fat yield was 9.65% ± 1.1 at 60°C, 30 MPa and 4 h where the yield was comparable and yet was achieved at more energy-efficient extraction conditions than in previous studies. The current study provides a better understanding of the physicochemical properties of Dragon variety mango kernel fat for various food applications.

Preparation of Low-Diacylglycerol Cocoa Butter Equivalents by Hexane Fractionation of Palm Stearin and Shea Butter.

Herein, we prepared 1,3-dipalmitoyl-2-oleoyl glycerol (POP)-rich fats with reduced levels of diacylglycerols (DAGs), adversely affecting the tempering of chocolate, via two-step hexane fractionation of palm stearin. DAG content in the as-prepared fats was lower than that in POP-rich fats obtained by previously reported conventional two-step acetone fractionation. Cocoa butter equivalents (CBEs) were fabricated by blending the as-prepared fats with 1,3-distearoyl-2-oleoyl glycerol (SOS)-rich fats obtained by hexane fractionation of degummed shea butter. POP-rich fats achieved under the best conditions for the fractionation of palm stearin had a significantly lower DAG content (1.6 w/w%) than that in the counterpart (4.6 w/w%) prepared by the previously reported method. The CBEs fabricated by blending the POP- and SOS-rich fats in a weight ratio of 40:60 contained 63.7 w/w% total symmetric monounsaturated triacylglycerols, including 22.0 w/w% POP, 8.6 w/w% palmitoyl-2-oleoyl-3-stearoyl-rac-glycerol, 33.1 w/w% SOS, and 1.3 w/w% DAGs, which was not substantially different from the DAG content in cocoa butter (1.1 w/w%). Based on the solid-fat content results, it was concluded that, when these CBEs were used for chocolate manufacture, they blended with cocoa butter at levels up to 40 w/w%, without distinctively altering the hardness and melting behavior of cocoa butter.

Cocoa butter symmetrical monounsaturated triacylglycerols: separation by solvent fractionation and application as crystallization modifier.

Symmetrical monounsaturated triacylglycerols-also known as SUS (saturated unsaturated saturated triacylglycerols)-are the main triacylglycerols present in cocoa butter (CB), exhibiting decisive influence in the tempering process conditions and sensorial characteristics in chocolate products. CBs with lower amounts of SUS do not crystallize adequately in chocolate processing, generating a low quality product with higher susceptibility to fat bloom formation. In this context, fractions with higher contents of SUS triacylglycerols were obtained by solvent fractionation of cocoa butter, under four operating conditions varying crystallization temperatures (17, 18, 20 and 22°C) and sample/acetone solvent ratios (1:7 and 1:5, in w/v). After solvent evaporation, CB fractions were evaluated in terms of triacylglycerol profile, solid fat content and melting point. The solvent fractionation performed at 17°C with a 1:7 ratio of cocoa butter:acetone favored the separation of a higher concentrated SUS stearin (denominated as S17) with 7.1% increment in SUS triacylglycerols, mainly StOSt-1-stearyl-2-oleoyl-stearin (26.9%) and POSt-1-palmitoyl-2-oleoyl-stearin (45.0%). Additionally, S17 was added to pure cocoa butter at three different proportions of CB:S17 (95:5, 90:10 and 80:20, in w/w) and the blend was evaluated by isothermal crystallization (at 17.5°C) and consistency (at 10, 15 and 20°C). Compared to the pure cocoa butter, at 10°C, the blend with 20% stearin (80:20) showed an increment of 67% in the consistency and considerable higher crystallization rates at 17.5°C were found, confirming the potential contribution of the SUS triacylglycerols as crystallization modifiers of CB.

Production of sn-1,3-distearoyl-2-oleoyl-glycerol-rich fats from mango kernel fat by selective fractionation using 2-methylpentane based isohexane

High-purity isohexane containing 88.12% 2-methylpentane, which has a higher polarity than industrial hexane, was selected to selectively fractionate mango kernel fat to produce 1,3-distearoyl-2-oleoyl-glycerol (SOS)-rich fat. The three-stage fractionation process was optimized by considering the stearin yield and its SOS content to obtain a third stearin (TS). This fat contained a high percentage of SOS (69.2%) with only 0.8% diacylglycerol. Mass spectra and sn-2 fatty acid analyses further revealed that the TS was mainly composed of symmetrical monounsaturated triacylglycerols. Compared with cocoa butter (CB), the unique composition of the TS improved its thermal properties (35.6% and 0% solid fat content at 35°C for the TS and CB, respectively). In particular, tempered binary fat blends, which were composed of 20–50% TS and 50–80% CB, showed acceptable compatibility at 20–28°C. The TS could be utilized by chocolate manufacturers to make products suitable for sale and consumption in tropical conditions.

Production of High‐Melting Symmetrical Monounsaturated Triacylglycerol‐Rich Fats from Mango Kernel Fat by Acetone Fractionation

Abstract1,3‐Distearoyl‐2‐oleoyl‐glycerol, 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl‐glycerol and 1‐stearoyl‐2‐oleoyl‐3‐arachidoyl‐glycerol are typical high‐melting symmetrical monounsaturated triacylglycerols (Hm‐SMT) found in cocoa butter improver (CBI). These triacylglycerols help to increase the hardness of chocolate products in tropical climates. In the present study, natural CBI products were produced from mango (Mangifera indica, Linn) kernel fat (MKF) by selective three‐stage fractionation using acetone. The second stearin (fraction I) from the first precipitate of MKF by fractionation for 180 min at 15 °C contained 86.9% of Hm‐SMT, and the third stearin (fraction II) obtained from fraction I by further fractionation for 180 min at 18 °C was enriched with 94.4% Hm‐SMT. High percentages of such triacylglycerols in these products contributed to higher slip melting points (36.5–37.7 °C) than commercial cocoa butter and cocoa butter equivalent (26.7 and 27.9 °C). Also, their differential scanning calorimetry properties and solid fat content values were superior to those in traditional confectionery fats, indicating that the tailored stearins could be used as ideal CBI. In particular, the hard fat blends consisting of 55–70% cocoa butter (CB) and 30–45% fraction II were considered as the preferred heat‐resistant chocolate ingredients. In addition, the mixture of the oleins (fraction III) was rich in diunsaturated and triunsaturated triacylglycerols and showed similar thermal properties to super palm oil, thus making it more suitable as special fat ingredients and modified fat sources.

Hepatic ceramides dissociate steatosis and insulin resistance in patients with non-alcoholic fatty liver disease

Recent data in mice have identified de novo ceramide synthesis as the key mediator of hepatic insulin resistance (IR) that in humans characterizes increases in liver fat due to IR ('Metabolic NAFLD' but not that due to the I148M gene variant in PNPLA3 ('PNPLA3 NAFLD'). We determined which bioactive lipids co-segregate with IR in the human liver. Liver lipidome was profiled in liver biopsies from 125 subjects that were divided into equally sized groups based on median HOMA-IR ('High and Low HOMA-IR', n=62 and n=63) or PNPLA3 genotype (PNPLA3(148MM/MI), n=61 vs. PNPLA3(148II), n=64). The subjects were also divided into 4 groups who had either IR, the I148M gene variant, both of the risk factors or neither. Steatosis and NASH prevalence were similarly increased in 'High HOMA-IR' and PNPLA3(148MM/MI) groups compared to their respective control groups. The 'High HOMA-IR' but not the PNPLA3(148MM/MI) group had features of IR. The liver in 'High HOMA-IR' vs. 'Low HOMA-IR' was markedly enriched in saturated and monounsaturated triacylglycerols and free fatty acids, dihydroceramides (markers of de novo ceramide synthesis) and ceramides. Markers of other ceramide synthetic pathways were unchanged. In PNPLA3(148MM/MI)vs. PNPLA3(148II), the increase in liver fat was due to polyunsaturated triacylglycerols while other lipids were unchanged. Similar changes were observed when data were analyzed using the 4 subgroups. Similar increases in liver fat and NASH are associated with a metabolically harmful saturated, ceramide-enriched liver lipidome in 'Metabolic NAFLD' but not in 'PNPLA3 NAFLD'. This difference may explain why metabolic but not PNPLA3 NAFLD increases the risk of type 2 diabetes and cardiovascular disease.

Monitoring batch lipase catalyzed interesterification of palm oil and fractions by differential scanning calorimetry

The melting profiles of palm oil, palm olein, and soft palm mid fraction were investigated by differential scanning calorimetry (DSC) before, during and after enzymatic interesterification. The DSC melting profiles of the three palm fats changed drastically due to the random redistribution of the fatty acids on the glycerol occurring upon interesterification. A high melting peak (already present for native palm oil) was observed for the three interesterified products and attributed to the increase in trisaturated triacylglycerols; modifications of the shape of the medium-melting peak (observed in the three products) were attributed to modifications within the mono-unsaturated triacylglycerols. In view of the drastic changes observed, the applicability of DSC to monitor enzymatic interesterification reactions was considered. While the degree of interesterification was supposed to be completed after 8 h according to the HPLC data, significant modifications were still observed within the DSC melting profiles. Minor changes within the structure of the medium-melting peak were selected as indicator of the reaction progress, and it was shown that intensities of DSC melting endotherms can be used to monitor the enzymatic interesterification reaction of these palm products.

Enzymatic Production of Cocoa Butter Equivalents High in 1‐Palmitoyl‐2‐oleoyl‐3‐stearin in Continuous Packed Bed Reactors

AbstractThis study aimed to optimize the lipase‐catalyzed transesterification of high oleic sunflower oil (A) with a mixture of ethyl palmitate and ethyl stearate (B) to produce cocoa butter equivalents with a weight ratio of 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl‐rac‐glycerol (POS) to total symmetric monounsaturated triacylglycerols (SMUT) that is similar to that of cocoa butter by response surface methodology. The reaction was performed in a continuous packed bed reactor, using 0.45 g of Lipozyme RM IM as the biocatalyst. The effects of temperature (Te), residence time (RT), substrate molar ratio (SR, B/A), and water content (WC) of the substrates on the composition of reaction products were elucidated using the models established. Optimal reaction conditions for maximizing total SMUT and POS contents while minimizing the levels of diacylglycerol formation and acyl migration were: Te, 60 °C; RT, 28.5 min; SR, 8.5; WC, 300 mg/kg. The contents of total SMUT, POS, and diacylglycerol in the reaction products and the content of palmitoyl and stearoyl residues at the sn‐2 position of triacylglycerols in the products were 52.0, 25.1, 9.4, and 4.8 %, respectively, under these conditions. Successful scale‐up of the reaction was achieved under the optimal conditions, using 5 g of the lipase. A silver‐ion high performance liquid chromatography analysis showed that the products obtained by the larger scale reaction contained 49.1 % total SMUT and 6.1 % of their positional isomers.

Phase behavior of symmetrical monounsaturated triacylglycerols

The unique properties of cocoa butter (CB) are due to the fact that it is composed, for the most part, of just three TAGs, 1,3‐dipalmitoyl‐2‐oleoylglycerol (POP), 1,3‐distearoyl‐2‐oleoylglycerol (StOSt), and rac‐1‐palmitoyl‐2‐oleoyl‐3‐stearoylglycerol (POSt). In this study we have examined blends, at 10% intervals, across the ternary of these three TAG by stabilizing them during a lengthy temperature regime designed to induce the most stable polymorph at the point of melting. The liquidus observed is in good agreement with that predicted using the Hildebrand model. A eutectic is seen in each binary system, with a possible ternary eutectic present at about POP:POSt 1:1 and <10% StOSt. CB stabilized following the same regime exhibits solid fat contents much greater than those obtained following the standard IUPAC 2.150(b) stabilization, likely to be due to the presence of the βVI polymorph rather than the βV form.Practical applications: The processing characteristics and final properties of fat based products depend greatly on the composition, crystallization, and melting properties of the fat or fats involved. In the case of chocolate and confectionery, this fat is CB. The present study confirms many of the relevant published phase diagrams and emphasizes the compositional areas having similar melting behavior to that of CB and, hence, suitable for cocoa butter equivalents.

Cocoa butter equivalents prepared by blending fractionated palm stearin and shea stearin

The aim of this study was to assess the possibility of commercial use as a cocoa butter equivalent (CBE). The CBE was prepared by blending fractionated palm stearin and shea stearin in a weight ratio of 40:60 and contained 81.9% total symmetric monounsaturated triacyl-glycerols. The CBE was blended with cocoa butter in weight ratios (CBE:cocoa butter) of 5:95, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, and 90:10. The blends were evaluated for their fatty acid and triacylglycerol compositions, thermal melting/crystallization behaviors, and solid fat content. The 5:95, 10:90, 20:80, and 30:70 blends showed similar melting/crystallization temperature ranges and enthalpies to those of cocoa butter. Furthermore, they showed similar changes in solid fat content to those of cocoa butter as a function of temperature. These results indicate that the CBE can be blended with cocoa butter at 30% for the manufacture of chocolate products without significantly altering their physical properties.

Selective enrichment of symmetric monounsaturated triacylglycerols from palm stearin by double solvent fractionation

The aim of this study was to produce a fractionated palm stearin enriched in symmetric monounsaturated triacylglycerols (SMUT), such as 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), 1-palmitoyl-2-oleoyl-3-stearoyl-rac-glycerol (POS), and 1,3-distearoyl-2-oleoyl-glycerol (SOS) using two-stage acetone fractionation. Palm stearin, containing 27.2 g/100 g total SMUT and 33.8 g/100 g tripalmitin was used as the starting material for the fractionation. A liquid fraction produced from palm stearin under the best conditions (temperature, 17 °C; volume-to-weight ratio of acetone to palm stearin, 8; crystallization time, 8 h) established in this study was free of tripalmitin (<0.5 g/100 g) and contained 44.5 g/100 g total SMUT (∼37.3 g/100 g POP, ∼6.4 g/100 g POS, and ∼0.8 g/100 g SOS). The yield of the liquid fraction was 61.3 g/100 g of the initial palm stearin weight. The liquid fraction was crystallized to further increase SMUT concentration. After fractionation at 4 °C for 24 h, a solid fraction with total SMUT content of 63.2 g/100 g (∼53.0 g/100 g POP, ∼9.1 g/100 g POS, and ∼1.1 g/100 g SOS) was obtained and its yield was 30.8 g/100 g of initial palm stearin weight. The resulting fractionated palm stearin would be suitable for use in preparing cocoa butter equivalents due to the high SMUT content.

Crystallization of model fat blends containing symmetric and asymmetric monounsaturated triacylglycerols

AbstractIn this study, the crystallization and melting properties of four different fat blends with the same saturated fat content (30%) but with different ratios of symmetric and asymmetric monounsaturated triacylglycerols were investigated using pNMR, DSC and polarized light microscopy. Blends were either palmitic (P) or stearic (S) based, and were combinations of SatOSat‐rich (Sat = saturated, O = oleic) and SatSatO‐rich vegetable oils with high‐oleic sunflower oil. The DSC results demonstrate that there was almost no difference in crystallization mechanism and crystallization rate between the two P‐based blends. Both blends showed a two‐step crystallization, which can be explained by polymorphism. Stop‐and‐return DSC results suggested an initial crystallization into an unstable polymorph followed by polymorphic transition during the crystallization. For the S‐based blends there was a clear difference between the SOS‐rich and the SSO‐rich blend, with a slower crystallization for the SSO‐rich blend. Possibly, this can be explained by fractional crystallization. The microstructure did not differ greatly between the blends. Directly after crystallization, the crystals of the SSO‐rich blend were slightly larger than the crystals of the SOS‐rich blend.

Structure and polymorphism of trans mono-unsaturated triacylglycerols

Structure and polymorphism of trans mono-unsaturated triacylglycerols

Structures of mono-unsaturated triacylglycerols. V. The β′1-2, β′-3 and β2-3 polymorphs of 1,3-dilauroyl-2-oleoylglycerol (LaOLa) from synchrotron and laboratory powder diffraction data

The crystal structures of the beta'(1)-2, the beta'-3 and the beta(2)-3 polymorphs of 1,3-dilauroyl-2-oleoylglycerol have been solved from powder diffraction data. The packing of the beta(2)-3 polymorph is similar to that of other cis mono-unsaturated triacylglycerols. Both the beta' polymorphs are crystallized in a novel type of packing in which one of the saturated lauroyl chains is packed side-by-side with part of the unsaturated oleoyl chain.

Structure and polymorphism oftransmono-unsaturated triacylglycerols

Structure and polymorphism of<i>trans</i>mono-unsaturated triacylglycerols

Structures of mono-unsaturated triacylglycerols. IV. The highest melting β′-2 polymorphs of trans-mono-unsaturated triacylglycerols and related saturated TAGs and their polymorphic stability

The beta'(1)-2 crystal structures of a series of mixed-chain saturated and trans-mono-unsaturated triacylglycerols containing palmitoyl, stearoyl and elaidoyl acyl chains have been solved from high-resolution powder diffraction data, from synchrotron as well as laboratory X-ray sources. The structures crystallized in the space group I2 with two independent molecules forming a dimer in the asymmetric unit, and packed in double-chain length layers. Unlike the corresponding beta-2 structures the solved beta'(1)-2 structures have different molecular conformations for the symmetric and the asymmetric mixed triacylglycerols, both with the sn-2 chain in a leg position of the chair-shaped conformation. A transformation to the beta-2 structure with the sn-2 chain in the back position is complicated and unlikely to take place in the solid state. A novel beta'-2 polymorph of PSS has been crystallized and its structure has been solved. The melting point (239 K) of this so-called beta'(0)-2 polymorph is 2 K above that of the beta'(1)-2 polymorph and almost equal to that of the beta-2 polymorph of PSS. The difference in packing of the beta'(0)-2 versus beta'(1)-2 structure explains the slow beta'(1)-2 to beta'(0)-2 phase transition. The transition is strikingly similar to the beta(2)-3 to beta(1)-3 transition in cis-mono-unsaturated triacylglycerols.

Structures of mono-unsaturated triacylglycerols. III. The β-2 polymorphs of trans-mono-unsaturated triacylglycerols and related fully saturated triacylglycerols

The beta-2 crystal structures of a series of saturated and trans-mono-unsaturated triacylglycerols (TAGs) have been solved from high-resolution powder synchrotron diffraction data. The series comprises symmetric as well as asymmetric even-numbered TAGs and the trans-mono-unsaturated ones all have a single elaidoyl chain. The structures have been solved with the direct-space parallel-tempering program FOX and refined with the Rietveld program GSAS. The beta-2 structures all crystallized in the space group P\bar 1 with the same molecular conformation. Within the resolution of the data no significant difference in packing or conformation is observed between trans-mono-unsaturated TAGs and saturated (stearoyl or palmitoyl) chain-containing analogues, in spite of the lower melting points of the former. An analysis of the position of the stepped methyl end-plane in the various subgroups of TAGs confirms most but not all suppositions found in the literature.

The crystal structures of the β1and β2polymorphs of mono-unsaturated triacylglycerols and cocoa butter determined from high resolution powder diffraction data

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The crystal structures of the β1and β2polymorphs of mono-unsaturated triacylglycerols and cocoa butter determined from high resolution powder diffraction data

We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our <a href="/publishing/faq?lang=en" class="text-primary">Help/FAQ</a> page and let us know.