Interesterification Research Articles

Interesterification of fat blends containing high oleic oils: Physical properties and dialkyl‐ketones formation assessment

AbstractIn view of the nutritional disadvantages of partial hydrogenation (production of unhealthy trans fats) interesterification (IE) has emerged to produce suitable fats for trans‐free formulations that have improved physicochemical properties. In this context, both chemical (CIE) and enzymatic (EIE) interesterification techniques can be used. However, it has been found that CIE technology may produce process‐related by‐products known as dialkyl‐ketones (DAK). The current study aims at investigating the formation of DAK during IE. Therefore, five edible oils and fats were selected based on their potential use in IE: Elaeis Guineensis palm stearin (POSt), high oleic palm stearin (HOPSt), palm kernel stearin (PKSt), high oleic sunflower oil (HOSO) and high oleic palm oil (HOPO). The investigated blends were divided into HOPO‐based blends (POSt:HOPO 50:50, PKSt:HOPO 50:50, HOPSt:HOPO 50:50 and 30:70 wt:wt%) and HOSO‐based blends (POSt:HOSO 30:70, 50:50 and 70:30 wt:wt%). They were all subjected to both CIE (using sodium methoxide) and EIE (using TLIM lipase as catalyst); analyses of physical properties and determination of DAK content were performed before and after IE. This study demonstrates that DAK were not formed during the EIE process regardless of the investigated matrix, whereas they were produced during CIE, and that they require sufficient rearrangement of triglycerides (TAG) to be formed. It has also been shown that unsaturated fatty acids are more prone to form DAK regardless of the fat matrix. However, there is no linear relationship between the amount of DAK and the amount of unsaturated fat in the matrix.

Enzymatic Interesterification of Cold-Pressed Maqui (Aristotelia chilensis (Mol.) Stuntz) Seed Oil and Belly Oil from Rainbow Trout (Oncorhynchus mykiss) Through Supercritical CO2

A new antioxidant lipid (AL) was synthesized from rainbow trout (Oncorhynchus mykiss) belly oil and cold-pressed maqui (CPM) (Aristotelia chilensis (Mol.) Stuntz) seed oil via enzymatic interesterification using Thermomyces lanuginosus in supercritical CO2 medium. A Box–Behnken design with 15 experiments was employed, with the independent variables being the following: belly oil/CPM oil ratio (10/90, 50/50, and 90/10, w/w), supercritical CO2 temperature (40.0, 50.0, and 60.0 °C), and supercritical CO2 pressure (100.0, 200.0, and 300.0 bar) for enzymatic interesterification. A multiple optimization was conducted based on the response variables yield and eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and tocopherol contents. The optimized conditions for the AL synthesis were: 81.4/18.6 (w/w), 40.0 °C and 299.99 bar, respectively. The corresponding responses variables were: 77.10% for yield, 5.12 and 4.95 g·100 g−1 total fatty acids for EPA and DHA, respectively, and 217.96, 4.28, 3.48, 64.48, and 6.39 mg·kg−1 oil for α-tocopherol, α-tocotrienol, β-tocopherol, γ-tocopherol, and δ-tocopherol, respectively. A novel AL was successfully synthesized starting from two abundant natural resources commonly considered as by-products during industrial processing. In agreement with the high EPA, DHA, and tocopherol presence, this AL can be recommended to be employed in nutritional and therapeutic supplements, according to its health benefits, particularly concerning antioxidant and anti-inflammatory properties.

Enzymatic interesterification of perilla seed oil and palm stearin: A sustainable approach to develop a novel zero-trans-fat margarine rich in omega-3 fatty acids.

The study focuses on developing a novel perilla seed oil (PeO)-based polyunsaturated fatty acid-rich margarine fat analogue using enzymatic interesterification. PeO is a rich source of omega-3 fatty acids, however, has limited application due to susceptibility to oxidative and thermal degradation. Moreover, low consumption of omega-3 fatty acids in modern diets serves as a major cause for increased prevalence of cardiovascular diseases. The stability of such oils can be improved by techniques like blending and interesterification. However, blending lacks uniformity, which can be overcome by interesterification. The process conditions, namely, enzyme load, temperature, substrate molar ratio, and reaction time, were systematically optimized using response surface methodology. The optimized interesterified fat was characterized for fatty acid and triacylglyceride (TAG) composition. The physicochemical and functional properties, along with oxidative stability, were also evaluated to determine its overall quality. The structured lipid with zero trans and low saturated fat was developed with 50:50 substrate molar ratio of PeO and palm stearin at 54°C within 5.4h at 6.2% w/w concentration of TLIM enzyme. It exhibited 23.8% degree of interesterification, 435.5g hardness, and 33°C slip melting point. The TAG profile of the resulting fat was significantly modified with increased triunsaturated TAGs like LnLnLn and LnLnL but reduced trisaturated TAGs like PPP. The interesterification process lowered tocopherol composition by 3%. The acid, peroxide, IP (Induction Period), and p-anisidine values of PeO significantly enhanced. The thermal behavior of the developed fat was also modified. The textural properties of margarine developed from optimized fat were comparable to commercial margarine, revealing the application of PeO in healthy margarine formulation.

A novel synthesis method of medium- and long-chain triglyceride lipids from rubber seed oil catalyzed by enzymatic interesterification and its metabolism mechanism.

Medium- and long-chain triglyceride (MLCT) is a striking structural lipid for the supply of energy and essential fatty free acids (FFAs) in the food field. This study aimed to prepare MLCT by enzymatic interesterification of rubber seed oil (RSO) and medium-chain triglyceride (MCT). Fortunately, the conversion of synthesized MLCT could reach 75.4% by the catalysis of Novozym 40086 (7 wt% to MCT) at a temperature of 40 °C with the substrate mole ratio of 1 : 0.7 (RSO : MCT). The as-synthesized MLCT contained unsaturated fatty acid (USFA, 50.13%) at the sn-2 position and exhibited superior performance on the acid value, peroxide value and iodine value in contrast to grade III soybean oil. Moreover, it exhibited the simultaneous release of LCFAs and MCFAs, extremely facilitating the reduction of body weight gain and control of the level of lipids in the blood. Finally, the preferred hepatic metabolism process of the obtained MLCT was proven to be the main cause of the reduced body weight and improved lipid levels by the in vivo deposition experiments. Therefore, our study suggested that the outstanding performance of the MLCT synthesized by RSO in foods as functional lipids.

The Method That Makes Oils and Fats Healthier: Interesterification

Lipids, which provide various additives to the food industry, are developed with various modification techniques. In addition to hydrogenation and fractionation techniques, interesterification has become widespread in recent years. This technique, which has been used for more than a century, is classified as chemical or enzymatic interesterification, depending on the use of metal alcoholate or enzyme as a catalyst during the redistribution of fatty acids in the triglyceride ester on glycerol. Since the partial hydrogenation technique has been abandoned due to the formation of trans fatty acid, interesterification is carried out in the production of trans fat-free oil, in the production of breast milk substitutes, in the optimization of cocoa butter substitutes and equivalents, in the formation of structured lipids with nutritional advantages and in the lipid composition in the edible film. With its expanding area of use, its effect on health has been investigated, and the information obtained from studies on humans is that it does not have a negative effect. However, more work is needed on this subject. On the other hand, the World Health Organization recommends consumption of interesterified fats in order to reduce trans fat consumption. The objective of this review was to gather information about interesterification which has become widespread in the oil industry and has been used in new products. The outcome of this study could help better understanding and utilization of interesterification for future research and applications.

Enzymatic synthesis of structured lipids rich in α‐linolenic acid: impacts of triacylglycerol profile on physicochemical characteristics

SummaryMedium‐ and long‐chain triacylglycerols rich in α‐linolenic acid (ALA‐MLCT) are a kind of functional structural lipids that provide ω‐3 fatty acid and faster energy supply to human body. To improve the functional and nutritional properties of vegetable oils, we proposed an effective strategy for the synthesis of ALA‐MLCT by enzymatic interesterification of coconut oil and flaxseed oil. Lipase UM1 exhibited the highest interesterification activity compared with commercial Lipozyme RM IM, Lipozyme TL IM and Novozym 435. MLCT (76.59%) and ALA‐MLCT (45.03%) were obtained under the optimum reaction conditions: substrate molar ratio (coconut oil/flaxseed oil) 1:1, temperature 40 °C, Lipase UM1 loading 25 U g‑1. Furthermore, we identified 14 characteristic triacylglycerols molecules between enzymatic interesterification and physical blend by orthogonal partial least squares‐discrimination analysis (OPLS‐DA) model. The content of triunsaturated type triacylglycerols in enzymatic interesterification product (11.29%) was lower than that of physical blend (36.25%). Enzymatic interesterification product had lower solid fat content and 2.44 times oxidative stability than physical blend. These findings provide an effective strategy for the synthesis of functional ALA‐MLCT and advance the understanding of the relationship between triacylglycerols composition and physicochemical characteristics.

Enzymatic Interesterification of Coconut and Hemp Oil Mixtures to Obtain Modified Structured Lipids.

The interesterification process allows structured lipids (SLs) to be obtained with a modified triacylglycerol (TAG) structure, in which the unfavorable saturated fatty acids (SFAs) are replaced with nutritionally significant fatty acids (FAs) such as monounsaturated (MUFAs) and polyunsaturated (PUFAs). Oxidative stability is crucial for the quality of SLs. This study aimed to characterize and evaluate the FA profile and oxidative stability of SLs synthesized by the enzymatic interesterification of hemp seed oil (HO) and coconut oil (CO) blends. Blends were prepared in three ratios (75% HO:25% CO, 50% HO:50% CO, and 25% HO:75% CO) and interesterified using sn-1,3 regiospecific lipase for 2 or 6 h. FA composition, the FA distribution of TAGs, acid value (AV), peroxide value (PV), and oxidation time were analyzed and compared to non-interesterified blends. Results showed no significant difference in the SFA:MUFA ratios between interesterified and non-interesterified blends with the same proportions. Lauric acid predominantly occupied the sn-2 position in all blends. Interesterified blends had higher AVs, exceeding codex standards, while PVs remained within the acceptable limits. Blends with 75% HO had lower oxidation times compared to those with 75% CO, with no significant difference between interesterified and non-interesterified blends. In the interesterification process of the studied blends, new TAGs with a modified structure were created, which may affect their physical and nutritional properties. This process also had a significant effect on the AV and PV levels, but not on the oxidation time of the modified blends. Therefore, it is necessary to remove free FAs after the enzymatic process to produce SLs characterized by improved hydrolytic stability. This will lead to better technological properties compared to the original oils. Further research is also necessary to enhance the oxidation stability of SLs obtained from blends of CO and HO to improve their storage stability.

Production of Margarine Fat Containing Medium- and Long-Chain Triacylglycerols by Enzymatic Interesterification of Peony Seed Oil, Palm Stearin and Coconut Oil Blends.

This paper reports the preparation of margarine fat using Lipozyme TL IM as a catalyst and peony seed oil (PSO), palm stearin (PS) and coconut oil (CO) as raw materials. The results indicate that there were no significant changes in fatty acid composition before or after interesterification of the oil samples. However, the total amount of medium- and long-chain triglycerides (MLCTs) increased from 2.92% to 11.38% in sample E1 after interesterification, mainly including LaLaO, LaMO, LaPM, LaOO, LaPO and LaPP. Moreover, the slip melting point (SMP) of sample E1 decreased from 45.9 °C (B1) to 33.5 °C. The solid fat content (SFC) of all the samples at 20 °C was greater than 10%, indicating that they could effectively prevent oil exudation. After interesterification, the samples exhibited a β' crystal form and could be used to prepare functional margarine.

Inter-esterified blends of Palm kernel oil, Palm oil, Palm oil Fractions and their derivatives as low Trans and low-cost fats as potential cocoa butter substitutes

Cocoa Butter Substitutes (CBS) were produced from Chemical Inter-esterification (CIE) of Fully Hydrogenated Palm Oil (FHPO), Fully hydrogenated Palm Kernel Oil (FHPKO), Palm Kernel Oil (PKO), Stearin fraction of Palm Oil (PPO), Olein fraction of Palm Oil (PO) blends in various quantitative proportions and Inter-esterified to form Inter-esterified Fats (IEF). The CIE reactions were carried outat 110○C for 1 hour using Sodium methoxide at 0.2% as a catalystwith a mixing speed of 200 rpm. The physical and chemical properties, melting profile, Solid Fat Content (SFC) were analyzed andcompared with commercially marketed cocoa butter. CIE substantially altered the fatty acid distribution in the triglyceride profileof the fat blends, culminating in a significant change in the melting profile of Inter-esterified Fats (IEF) as compared to their Physical Blends (PB). CBS obtained from CIE of blends of pure Lauric Oils and their fully hydrogenated products are found to be the closest to Cocoa butter in terms of melting profile followed by HPKO: PKO (50:50) and HPKO: PKO (60:40) showing N35 (Solid fat content at 35C of almost 0%) making them most suitable alternative for Cocoa Butter. While Lauric and Non Lauric oil blends such as FHPKO: FHPO (20:80), FHPO: FHPKO (30:70), and 40:60 (PPO: FHPKO) indicated a high potential option as Low trans-CBS in Confectionery Industry and Frozen Dessert Fat as they exhibited similar SFC curves and melting profile to the commercial Cocoa Butter (CB).

Formulasi campuran olein minyak sawit untuk memproduksi shortening bebas lemak trans [Formulation of palm oil olein mixture to produce trans-fat-free shortening

Shortening is a solid fat with the functional properties needed to produce a better texture and appearance for bakery or confectionery products, as well as frying and cooking media. Shortening is made by mixing two or more vegetable oils and then modifying them through a chemical or enzymatic interesterification process. In this research, the raw material for shortening was prepared from a mixture of 2 types of palm oil olein: refined olein (ROL) and mid olein (MOL). This research aimed to determine the optimal ROL and MOL mixture ratio in the chemical interesterification process, which produces shortening with the best quality and specifications. Five levels of ROL/MOL comparison consisting of (100/0), (95/5), (90/10), (85/15), and (80/20) were chemically inter-esterified using a sodium methoxide catalyst under a vacuum of 0.8 bar at a temperature of 110 oC and speed of 500 rpm. The results showed that the increase of MOL in the ROL/MOL formulation tends to increase the shortening melting point. However, increasing MOL did not change the iodine value, and all the ROL/MOL ratios produced shortening with specifications that met the SNI 3718:2018 requirement, and the best ROL/MOL ratio was 80/20.

Batch and continuous enzymatic interesterification of beef tallow: Interesterification degree, reaction relationship, and physicochemical properties

The relationship between batch and continuous enzymatic interesterification was studied through enzymatic interesterification of beef tallow. The interesterification degree (ID) during the batch reaction was monitored based on triacylglycerol composition, sn-2 fatty acid composition, solid fat content, and melting profile and was described by an exponential model. A relationship equation featuring reaction parameters of the two reations was established to predict the ID and physicochemical characteristics in continuous interesterification. The prediction of the ID based on triacylglycerol composition was reliable, with an R2 value greater than 0.85. Interesterification produced more high-melting-point components for both reactions, but the acyl migration in the batch-stirring reactor was much greater, resulting in faster crystallization, a more delicate crystal network, and lower hardness. The relationship equation can be employed to predict the ID, but the prediction of physicochemical properties was constrained by the difference in acyl migration degree between the two reactions.

Streamlined enzymatic synthesis of human milk fat substitutes

The positional distribution of palmitic acid (PA) in human milk fat substitutes (HMFSs) plays a pivotal role in mimicking the nutritional profile of human milk fat for nourishing non-breastfed infants. This study innovatively introduced a streamlined enzymatic process for preparing HMFSs rich in sn-2 PA using palm stearin, a PA-rich source without the necessity for positional distribution of PA. The initial step involved enhancing the sn-2 PA concentration through enzymatic interesterification using Lipase UM1, which exhibited superior catalytic efficiency than Novozym 435. This process increased the sn-2 PA level from 40.98 % to 64.51 %. Subsequently, acidolysis was employed to reduce PA levels by replacing PA at sn-1,3 positions using sn-1,3-regioselective lipases. The PA content decreased from 60.64 % to 26.73 %, simultaneously raising the relative sn-2 PA concentration to 71.57 %, meeting the benchmarks for HMFSs. This study establishes a robust conceptual framework for the prospective industrial synthesis of HMFSs.

Stability of perilla seed oil based PUFA-rich structured lipids using enzymatic interesterification: A thermo-oxidative kinetic study

Enzymatic interesterification (EIE) serves as a viable approach for enhancing the stability and functional characteristics of fats and oils rich in polyunsaturated fatty acid (PUFA) such as perilla seed oil (PSO). This investigation conducted a comprehensive analysis of the oxidative stability and kinetics behaviour of PUFA-rich enzymatically interesterified structured lipids (SL) developed using PSO. Further, these SL were enriched with varying concentration of rosemary extract (RE) and their stability was assessed using rancimat method under accelerated temperature (90–120 °C). Initial assessment of oxidative indices revealed that the obtained SL exhibited lower primary (peroxide and conjugated diene) and secondary indices (p-anisidine and conjugated trienes) compared to PSO. Furthermore, fatty acid composition analysis revealed that incorporation of PSO into palmolein during interesterification resulted in reduction of PUFA content in the obtained SL, thus achieving a balanced saturated: monounsaturated: polyunsaturated ratio of fatty acid (1.2:1.2:1) in SL. The analysis of kinetic parameters demonstrated that SL displayed lower activation energies (Ea,106.17 kJ/mol), frequency factor (A, 22.38 ×1013), activation enthalpies (∆H++,103.03 kJ/mol) and entropies (∆S++, 19.52 J/mol K) as well as more negative temperature coefficient (Tc, −8.96) compared to PSO. RE incorporation at the level of 1500 ppm in SL have higher antioxidant efficacy with estimated shelf of 188 days (IP25) and comparable with BHT at 200 ppm. These results are validated using the principal component analysis and correlation analysis. The findings of the present study hold significant implications for the fat and oil industry, as the utilization of such SL can extend shelf-life while preserving the nutritional value of PUFA-rich oils.

Amelioration of nutritional properties of bakery fat using omega-3 fatty acid-rich edible oils: a review.

Bakery products have gained prominence in modern diets due to their convenience and accessibility, often serving as staple meals across diverse regions. However, the fats used in these products are rich in saturated fatty acids and often comprise trans fatty acids, which are considered as a major biomarker for non-communicable diseases like cardiovascular disorders, obesity and diabetes. Additionally, these fats lack the essential omega-3 fatty acids, which are widely known for their therapeutic benefits. They play a major role in lowering the risk of cardiovascular diseases, cancer and diabetes. Thus, there is need for incorporating these essential fatty acids into bakery fats. Nevertheless, fortifying food products with polyunsaturated fatty acids (PUFAs) poses several challenges due to their high susceptibility to oxidation. This oxidative deterioration leads to not only the formation of undesirable flavors, but also a loss of nutritional value in the final products. This review focuses on the development of healthier trans-fat-free bakery fat enriched with omega-3 fatty acids and its effect on the physicochemical, functional, sensory and nutritional properties of bakery fats and products. Further, the role of various technologies like physical blending, enzymatic interesterification and encapsulation to improve the stability of PUFA-rich bakery fat is discussed, where microencapsulation emerged as a novel and effective technology to enhance the stability and shelf life. By preventing deteriorative changes, microencapsulation ensures that the nutritional, physicochemical and sensory properties of food products remain intact. Novel modification methods like interesterification and microencapsulation used for developing PUFA-rich bakery fats have a potential to address the health risks occurring due to consumption of bakery fat having higher amount of saturated and trans fatty acids. © 2023 Society of Chemical Industry.

Effect of Linoleic and Linolenic Acid Contents on the Oxidation Stability of Interesterified Fats under Rancimat Test Conditions.

This study aimed to better understand the association between the amount of polyunsaturated fatty acids, namely, linoleic acid (LA) and linolenic acid (LNA), and the increases in the peroxide value that results from storing interesterified fats, which are used as sources of solid fats in edible oil and fat products, at high temperatures. Six interesterified fats with different LA and LNA contents were prepared and oxidized at 50°C, 60°C, 70°C, and 80°C under Rancimat test conditions. The oxidation rate increased with LA and LNA contents and increasing temperature. The oxidation kinetic analysis during the early oxidation stages demonstrated that when LA and LNA exceeded 8% and 2% respectively, the oxidative stability decreased as expected. However, the total LA and LNA contents had a higher correlation with the reaction rate constant [k (meq kg-1 h-1 )] than each amount of LA and LNA contained therein. In other words, the oxidation stability of the interesterified fats used in this study depended on the total LA and LNA contents.

Characterization of structured lipids produced through interesterification of blends comprising beef tallow, milk, and vegetable oil using infrared spectroscopy

AbstractThis study aimed to restructure beef tallow‐milk‐vegetable oils blends through the chemical and enzymatic interesterifications and to analyze some properties of interesterified lipids including peroxide value, free fatty acid and mono‐di‐triacylglycerol contents, fatty acid profile, and slip melting point. Moreover, the mid‐infrared spectra of the samples were obtained using Fourier transform infrared spectroscopy. The monounsaturated and polyunsaturated fatty acid contents of beef tallow increased by blending and interesterification reactions. The free fatty acid content of the enzymatically interesterified lipids was higher than that of the chemically interesterified fats. The slip melting point of the structured fats decreased after both blending and interesterification. A statistical model showed that infrared spectra combined with analytical data could discriminate the interesterified lipids from binary and ternary blends. It was found out that a 15% milk and 40% vegetable oil ratio in the initial blends yielded as end products which could be an alternative product of butterfat in the bakery industry after chemical interesterification.

Interesterified palm oil promotes insulin resistance and altered insulin secretion and signaling in Swiss mice

Interesterified fats have been used to replace trans-fat in ultra-processed foods. However, their metabolic effects are not completely understood. Hence, this study aimed to investigate the effects related to glucose homeostasis in response to interesterified palm oil or refined palm oil intake. Four-week-old male Swiss mice were randomly divided into four experimental groups and fed the following diets for 8 weeks: a normocaloric and normolipidic diet containing refined palm oil (PO group) or interesterified palm oil (IPO group); a hypercaloric and high-fat diet containing refined PO (POHF group) or interesterified PO (IPOHF group). Metabolic parameters related to body mass, adiposity and food consumption showed no significant differences. As for glucose homeostasis parameters, interesterified palm oil diets (IPO and IPOHF) resulted in higher glucose intolerance than unmodified palm oil diets (PO and POHF). Euglycemic-hyperinsulinemic clamp assessment showed a higher endogenous glucose production in the IPO group compared with the PO group. Moreover, the IPO group showed significantly lower p-AKT protein content (in the muscle and liver tissues) when compared with the PO group. Analysis of glucose-stimulated static insulin secretion (11.1 mmol/L glucose) in isolated pancreatic islets showed a higher insulin secretion in animals fed interesterified fat diets (IPO and IPOHF) than in those fed with palm oil (PO and POHF). Interesterified palm oil, including in normolipidic diets, can impair insulin signaling in peripheral tissues and increase insulin secretion by β-cells, characterizing insulin resistance in mice.

Texture and volatile profiles of beef tallow substitute produced by a pilot-scale continuous enzymatic interesterification.

Edible beef tallow (BT) has been widely used in Sichuan hotpot due to its unique flavor and texture. However, BT should not be consumed in excess caused by its trans-fatty acids and cholesterol issues. In this study, a BT substitute was prepared after enzymatic interesterification in a pilot-scale packed-bed reactor using soybean oil and fully hydrogenated palm oil (4:3, w/w) as feedstock. The products were characterized against BT in terms of fatty acid/triacylglycerol compositions, solid fat content, polymorphism, and melting/crystallization behaviors to select the most promising BT substitute. The optimal flow rate was 120mL/min. Changes in volatile compounds during stir-frying and simmering were also investigated for Sichuan hotpots made with these two oils. The volatile compounds of BT substitute were similar to that of natural BT. The findings will contribute to expanding the base oil categories of Sichuan hotpot oils.

Novel Approaches for Elongation of Fish Oils into Very-Long-Chain Polyunsaturated Fatty Acids and Their Enzymatic Interesterification into Glycerolipids.

Elongation of the Very-Long-Chain Fatty Acids-4 (ELOVL4) enzyme that is expressed in neuronal tissues, sperm, and testes mediates biosynthesis of very-long-chain polyunsaturated fatty acids (VLC-PUFAs) from dietary long chain PUFAs (LC-PUFAs). The VLC-PUFAs are critical for neuronal and reproductive function. Therefore, mutations in ELOVL4 that affect VLC-PUFA biosynthesis contribute to retinal degenerative diseases including Autosomal Dominant Stargardt-like Macular Dystrophy (STGD3). Recent studies have also shown not only a depletion of retinal VLC-PUFAs with normal aging but also a more significant loss of VLC-PUFAs in donor eyes of patients with age-related macular degeneration (AMD). However, currently, there are no natural sources of VLC-PUFAs to be evaluated as dietary supplements for the attenuation of retinal degeneration in animal models of STGD3. Here, we report the development of a novel chemical approach for elongation of eicosapentaenoic (C20:5 n-3) and docosahexaenoic (C22:6 n-3) acids from fish oils by 6 carbon atoms to make a unique group of VLC-PUFAs, namely all-cis-hexacosa-11,14,17,20,23-pentaenoic acids (C26:5 n-3) and all-cis-octacosa-10,13,16,19,22,25-hexaenoic acids (C28:6 n-3). The three-step elongation approach that we report herein resulted in a good overall yield of up to 20.2%. This more sustainable approach also resulted in improved functional group compatibility and minimal impact on the geometrical integrity of the all-cis double bond system of the VLC-PUFAs. In addition, we also successfully used commercial deep-sea fish oil concentrate as an inexpensive material for the C6 elongation of fish oil LC-PUFAs into VLC-PUFAs, which resulted in the making of gram scales of VLC-PUFAs with an even higher isolation yield of 31.0%. The quality of fish oils and the content of oxidized lipids were key since both strongly affected the activity of the PEPPSI-IPr catalyst and ultimately the yield of coupling reactions. Downstream enzymatic interesterification was used for the first time to prepare structured glycerolipids enriched with VLC-PUFAs that could be evaluated in vivo to determine absorption and transport to target tissues relative to those of the free fatty acid forms. It turned out that in the synthesis of structured triacylglycerols and glycerophospholipids with VLC-PUFAs, the polarity of the immobilized lipase carrier and its humidity were essential.

Effect of substrate composition on physicochemical properties of the medium-long-medium structured triacylglycerol.

Nutritional and functional qualities and applications of structured lipids (SL) depend on the composition and molecular structure of fatty acids in the glycerol backbone of triacylglycerol (TAG). However, the relationship between the substrate composition and physicochemical qualities of SL has not been revealed. The investigation aims to disclose the effect of substrate composition on the physicochemical properties of medium-long-medium structured lipids (MLM-SLs) by enzymatic interesterification of Lipozyme TLIM/RMIM. The medium-long-chain triacylglycerol (MLCT) yield could reach 70.32%, including 28.98% CaLCa (1,3-dioctonyl-2-linoleoyl glyceride) and 24.34% CaOCa (1,3-didecanoyl-2-oleoyl glyceride). The sn-2 unsaturated fatty acid composition mainly depended on long-chain triacylglycerol (LCT) in the substrate. The increased carbon chain length and double bond in triacylglycerol decreased its melting and crystallization temperature. The balanced substrate composition of MCT/LCT increased the size and finer crystals. Molecular docking simulation revealed that the MLCT molecule mainly interacted with the catalytic triplets of Lipozyme TLIM (Arg81-Ser83-Arg84) and the Lipozyme RMIM (Tyr183-Thr226-Arg262) by OH bond. The oxygen atom of the ester on the MLCT molecule was primarily bound to the hydrogen of hydroxyl and amino groups on the binding sites of Lipozyme TLIM/RMIM. The intermolecular interplay between MLCT and Lipozyme RMIM is more stable than Lipozyme TLIM due to the formation of lower binding affinity energy. This research clarifies the interaction mechanism between MLCT molecules and lipases, and provides an in-depth understanding of the relationship between substrate composition, molecular structure and physicochemical property of MLM-SLs. © 2023 Society of Chemical Industry.