Medium- And Long-chain Triacylglycerols Research Articles

Encapsulation and characterization of ω-3 medium- and long-chain triacylglycerols microencapsulated with different proteins as wall materials

In this study, ω-3 medium- and long-chain triacylglycerols (MLCTs) microcapsules with excellent performance were obtained using soy protein as the wall component to address the oxidation-related problems of MLCTs. Additionally, the effect of soy, whey, or pea proteins on microcapsules in terms of the changes in their structure and physicochemical properties was investigated. The results showed that the small particle size, low PDI (polydispersity index) and zeta potential, fast adsorption rate, and low interfacial tension of these protein-based samples fabricated through the O/W template method were conducive to maintaining the integrity of microcapsules during spray-drying. The microcapsules, characterized by a spherical shape, exhibited superior encapsulation efficiency of 94.56%, surpassing the findings of previous investigations. Overall, these microcapsules exhibited long-term storage stability and low controllable release rates, which could be utilized as carriers for liposoluble actives.

Novel Human Milk Fat Substitutes Based on Medium- and Long-Chain Triacylglycerol Regulate Thermogenesis, Lipid Metabolism, and Gut Microbiota Diversity in C57BL/6J Mice.

Human milk is naturally rich in medium- and long-chain triacylglycerols (MLCT), accounting for approximately 30% of the total fat. However, infant formula fat is prepared using a physical blend of vegetable oils, which rarely contains MLCT, similar to human milk. The differences in MLCT between human milk and infant formulas may cause different lipid metabolisms and physiological effects on infants, which are unknown. This study aimed to analyze the metabolic characteristics of formula lipid containing novel human milk fat substitutes based on MLCT (FL-MLCT) and compare their effects with those of the physical blend of vegetable oils (FL-PB) on lipid metabolism and gut microbiota in mice. Compared with the FL-PB group, the FL-MLCT group showed increased energy expenditure, decreased serum triacylglycerol level, and significantly lower aspartate aminotransferase level, epididymal and perirenal fat weight, and adipocyte size. Moreover, the abundances of Firmicutes/Bacteroidota, Actinobacteriota, and Desulfovibrionaceae were significantly decreased in the FL-MLCT group. Novel human milk fat substitutes MLCT could inhibit visceral fat accumulation, improve liver function, and modulate the mice gut microbiota composition, which may contribute to controlling obesity.

Enzymatic Synthesis of Structured Lipids Enriched with Medium- and Long-Chain Triacylglycerols via Pickering Emulsion-Assisted Interfacial Catalysis: A Preliminary Exploration.

Medium- and long-chain triacylglycerol (MLCT), as a novel functional lipid, is valuable due to its special nutritional properties. Its low content in natural resources and inefficient synthesis during preparation have limited its practical applications. In this study, we developed an effective Pickering emulsion interfacial catalysis system (PE system) for the enzymatic synthesis of MLCT by trans-esterification. Lipase NS 40086 served simultaneously as a catalyst and a solid emulsifier to stabilize the Pickering emulsion. Benefitting from the sufficient oil-water interface, the obtained PE system exhibited outstanding catalytic efficiency, achieving 77.5% of MLCT content within 30 min, 26% higher than that of a water-free system. The Km value (0.259 mM) and activation energy (14.45 kJ mol-1) were 6.8-fold and 1.6-fold lower than those of the water-free system, respectively. The kinetic parameters as well as the molecular dynamics simulation and the tunnel analysis implied that the oil-water interface enhanced the binding between substrate and lipase and thus boosted catalytic efficiency. The conformational changes in the lipase were further explored by FT-IR. This method could give a novel strategy for enhancing lipase activity and the design of efficient catalytic systems to produce added-value lipids. This work will open a new methodology for the enzymatic synthesis of structured lipids.

Encapsulation and characterization of soy protein-based ω-3 medium- and long- chain triacylglycerols microencapsulated with diverse homogenization techniques for improving oxidation stability

Recently, MLCTs have attracted considerable attention as a potential alternative to traditional oils due to their suppressive effect on fat accumulation and insulin sensitivity. In this study, the microcapsules of MLCTs with superior performance were fabricated through different homogenization processes to overcome the limitations of ω-3 medium- and long- chain triacylglycerols (MLCTs), including poor stability and prone oxidation. Additionally, the impact of various homogenization techniques, namely, high-pressure, ultrasound, and cavitation jet, on the particle structure, encapsulation efficiency, and oxidation stability of microcapsules (MLCTs) was investigated. The MLCTs microcapsules fabricated through high-pressure homogenization had a smaller particle size of 295.12 nm, lower PDI of 0.24, and a higher zeta-potential absolute value of 32.65, which significantly improved their dispersion and encapsulation efficiency, reaching 94.56 % after the spray-drying process. Furthermore, the low moisture content and superior storage stability of MLCTs microcapsules have the potential to serve as carriers of liposoluble actives.

Medium- and Long-Chain Triacylglycerol: Preparation, Health Benefits, and Food Utilization.

Medium- and long-chain triacylglycerol (MLCT) is a structured lipid with both medium- and long-chain fatty acids in one triacylglycerol molecule. Compared with long-chain triacylglycerol (LCT), which is mainly present in common edible oils, and the physical blend of medium-chain triacylglycerol with LCT (MCT/LCT), MLCT has different physicochemical properties, metabolic characteristics, and nutritional values. In this article, the recent advances in the use of MLCT in food formulations are reviewed. The natural sources and preparation of MLCT are discussed. A comprehensive summary of MLCT digestion, absorption, transport, and oxidation is provided as well as its health benefits, including reducing the risk of overweight, hypolipidemic and hypoglycemic effects, etc. The potential MLCT uses in food formulations, such as infant formulas, healthy foods for weight loss, and sports foods, are summarized. Finally, the current safety assessment and regulatory status of MLCT in food formulations are reviewed. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 15 is April 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Medium‐ and long‐chain triacylglycerol in human breast milk and association with maternal dietary patterns

AbstractThis study aims to investigate the influences of maternal dietary patterns on the triacylglycerol (TAG) composition, particular medium‐ and long‐chain triacylglycerol (MLCT) in human breast milk. A total of 180 Chinese human breast milk samples were collected and divided into three dietary patterns groups accounting to semi‐quantitative food intake frequency questionnaire and a 24‐h dietary recall. The 180 samples were from 121 mothers in Nanjing, all of whom were mature milk (1 month postpartum and 3 months postpartum). Using high performance liquid chromatography combined with quadrupole time‐of‐flight mass spectrometry, 108 TAGs were identified and quantified. In breast milk samples, MLCTs accounted for 25.76% (median of 24.63%; 95% CI: 24.60, 26.92) of the total TAGs. In human breast milk, the main type of MLCT is the triacylglycerol with one medium‐chain fatty acid and two long‐chain fatty acids (MLL type) which accounted for ~81% of total MLCTs. Among the molecular species of MLCT, O‐P‐La and O‐L‐La are the two most abundant configurations in MLCT (2.28% and 2.17% of total TAGs, respectively). MLCT in breast milk was positively correlated with the energy supply ratio of carbohydrates (p = 0.205), which was significantly higher than that of the other two groups (p = −0.150 and −0.232).

The composition, characterisation, and health impacts of human milk lipid medium‐ and long‐chain TAGs

SummaryMedium‐chain fatty acids (MCFAs) are naturally associated with human milk lipids and can also be associated with MCTs (medium‐chain triacylglycerols). Healthy lipids could be constructed from medium‐ and long‐chain triacylglycerols (MLCTs) composed of MCFAs. Biochemical and chemical catalysts catalyse many chemical and enzymatic processes, such as acidolysis, interesterification, and esterification. Due to their potential health benefits, MCTs and MLCTs are widely used as nutraceuticals in the pharmaceutical and food industries. This comprehensive overview of MLCTs evaluates their structures, compositions, nutritional properties, and supposed health benefits. This review identifies the key research gaps to overcome the MCFA‐TAG use when compared to human milk and infant formulas.

Synthesis of eicosapentaenoic acid-enriched medium- and long-chain triglyceride by lipase-catalyzed transesterification: a novel strategy for clinical nutrition intervention.

Eicosapentaenoic acid (EPA) has been recognized as a promising nutrient to improve therapeutic efficacy for cancer patients. Nevertheless, there are certain limitations to the application of EPA due to its structural characteristics. To maximize the nutritive value of EPA, a type of medium- and long-chain triacylglycerol (MLCT) enriched with EPA was designed and synthesized using the lipase-catalyzed transesterification of medium-chain triglyceride (MCT) and EPA-enriched fish oil (FO). The optimum synthesis conditions for EPA-enriched MLCT used Lipozyme RM as catalyst, and had a substrate mass ratio (MCT/EPA-enriched FO) of 3:1, lipase loading of 80 g kg-1 , a reaction temperature of 60 °C, and a reaction time of 6 h. The MLCT content was as high as 80.79% after the transesterification reaction and the purification, and the content of MLCT containing EPA accounted for 70.21%. The distribution of EPA at the sn-2 position showed a significant increase in MLCT compared with the original substrate, from 18.89% to 26.93%. The in vitro digestion results demonstrated that MLCT had a significantly higher EPA bioaccessibility than the original substrate. Eicosapentaenoic acid-enriched MLCT was developed. This may provide a novel strategy for clinical nutritional intervention. © 2023 Society of Chemical Industry.

Effects of Medium- and Long-Chain Structured Triacylglycerol on the Therapeutic Efficacy of Vitamin D on Ulcerative Colitis: A Consideration for Efficient Lipid Delivery Systems.

Due to intestinal malabsorption and poor water solubility, vitamin D (VitD) deficiency in ulcerative colitis (UC) continues to increase. Medium- and long-chain triacylglycerols (MLCT), as novel lipids, have been widely applied in the field of functional food and medicine nutrition. Our previous studies showed that the difference in MLCT structure could affect VitD bioaccessibility in vitro. In this study, our results further indicate that, although identical in fatty acid composition, structured triacylglycerol (STG) had a higher VitD bioavailability (AUC = 15470.81 μg/L × h) and metabolism efficacy [s-25(OH)D, p < 0.05] than physical mixtures of triacylglycerol (PM), which further affect the amelioration efficiency in UC mice. Compared with PM, the damage of colonic tissues, intestinal barrier proteins, and inflammatory cytokines in STG showed better amelioration at the same dose of VitD. This study provides a comprehensive understanding of the mechanism of nutrients in different carriers and a solution for developing nutrients with high absorption efficiency.

Effects of the Novel LaPLa-Enriched Medium- and Long-Chain Triacylglycerols on Body Weight, Glycolipid Metabolism, and Gut Microbiota Composition in High Fat Diet-Fed C57BL/6J Mice

The roles of medium- and long-chain triacylglycerols (MLCT) on health benefits under high fat diet (HFD) conditions remain in dispute. This study was conducted to investigate the effects of novel LaPLa-rich MLCT on the glycolipid metabolism and gut microbiota in HFD-fed mice when pork fat is half replaced with MLCT and palm stearin (PS). The results showed that although MLCT could increase the body weight in the mouse model, it can improve the energy utilization, regulate the glucose and lipid metabolism, and inhibit the occurrence of inflammation. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that PS and MLCT affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some operational taxonomic units (OTUs). Moreover, several OTUs belonging to the genera Dorea, Streptococcus, and g_Eryipelotrichaceae had a high correlation with obesity and obesity-related metabolic disorders of the host. Therefore, it can be seen that this new MLCT has different properties and functions from the previous traditional MLCT, and it can better combine the advantages of MLCT, lauric acid, and sn-2 palmitate, as well as the advantages of health function and metabolism. In summary, this study explored the effects of LaPLa-enriched lipids on glycolipid metabolism in mice, providing theoretical support for future studies on the efficacy of different types of conjugated lipids, intending to apply them to industrial production and subsequent development of related products.

Preparation of functional oils rich in diverse medium and long-chain triacylglycerols based on a broadly applicable solvent-free enzymatic strategy

To address the problems of long reaction times and limited range of adaptation in enzymatic synthesis medium- and long-chain triacylglycerols (MLCTs), a broadly applicable solvent-free enzymatic interesterification strategy was proposed. Candida sp. lipase (CSL) was immobilized on hydrophobic hollow mesoporous silica spheres (HHSS) to construct a biocatalyst designated as CSL@HHSS with a 15.3 % immobilization yield and a loading amount of 94.0 mg/g. The expressed activity and the specific activity were 20.14 U/g and 173.62 U/g, which were 4.6 and 5.6 times higher than that of free CSL, respectively. This biocatalyst demonstrated higher activity, wider applicability, and excellent reusability. Linseed oil, sunflower oil, perilla seed oil, algal oil, and malania oleifera oil were applied as substrates to produce MLCTs with medium-chain triacylglycerols (MCT) catalyzed by CSL@HHSS through interesterification in yields ranging from 69.6 % to 78.0 % within 20 min. Specific fatty acids, including linolenic acid, oleic acid, DHA, and nervonic acid (the first reported), were introduced into MLCT's skeleton, respectively. The structures were finely analyzed and identified by GC and UPLC-MS. The catalytic efficiency value of CSL@HHSS in catalyzing interesterification between linseed oil and MCT (70 ℃, 20 min, lipase 6 wt%) is 0.86 g/g∙min, which is the highest ever reported. This paper presents an effective and sustainable strategy for functional MLCTs production.

Medium- and long-chain triacylglycerols and di-unsaturated fatty acyl-palmitoyl-glycerols in Chinese human milk: Association with region during the lactation.

The triacylglycerols (TAGs) of medium- and long-chain triacylglycerols (MLCT) and di-unsaturated fatty acyl-palmitoyl-glycerols (UPU) in human milk provide better nutritional effects, and should be prioritized as crucial focuses on neonatal nutrition research. However, little has been done on the influences of the lactation stage and regional diversity on MLCT and UPU. In this study, we collected 204 human milk samples during colostrum, 1st and 4th month from the north (Baotou), central (Beijing), east (Jinan), southwest (Kunming), southeast (Shenzhen), and northwest (Xining) regions of China. There were 122 species of TAGs detected with UPLC-Q-TOF-MS, including 60 kinds of MLCT and 15 kinds of UPU. The MLCT and UPU type TAGs in human milk were ~27 and ~38%, respectively. The sum content of MLCT and UPU in human milk was stable. Compared to the regional diversity, lactation stages showed more obvious influences on MLCT and UPU composition. Moreover, a summary of TAG studies indicated that Chinese human milk showed a higher ratio of O-P-L to O-P-O than in western countries.

Digestion of Medium- and Long-Chain Triacylglycerol and sn-2 Palmitate in Infant Formula: A Study Based on Dynamic In Vitro Simulation of Infant Gastrointestinal Lipolysis.

In this study, lipolysis of triacylglycerols (TAGs) in infant formula (IF) composed of different oils and supplied with different structured TAGs, including medium- and long-chain triacylglycerol (MLCT) and sn-2 palmitate, was studied using a dynamic digestion model simulating the infant gastrointestinal tract. The molecular species of digestion products released during digestion, including diacylglycerols, monoacylglycerols (MAGs), and free fatty acids, as well as undigested TAGs, were identified and quantified using liquid chromatography-mass spectrometry. We observed clearly different lipolysis degrees (LDs), with diversity in digestion products of different IFs. IFs supplied with MLCT showed moderate medium-chain fatty acid release during gastric digestion and higher LD after intestinal digestion. The presence of sn-2 palmitate in IF was associated with higher content of MAG-16:0 in digestion products. The species and contents of digestion products in IF were highly influenced by structured TAGs.

Green synthesis of polydopamine functionalized magnetic mesoporous biochar for lipase immobilization and its application in interesterification for novel structured lipids production

In this study, the polydopamine functionalized magnetic mesoporous biochar (MPCB-DA) was prepared for immobilization of Bacillus licheniformis lipase via covalent immobilization. Under optimized immobilization conditions, the maximum immobilization yield, efficiency and immobilized lipase amount were found to be 45%, 54% and 36.9 mg/g, respectively. The immobilized lipase, MPCB-DA-Lipase showed good thermal stability and alkali resistance. The MPCB-DA-Lipase retained 56% initial activity after 10 reuse cycles, with more than 85% relative activity after 70 days’ storage at 4 or 25 °C. The MPCB-DA-Lipase was efficiently applied in the interesterification of Cinnamomum camphora seed kernel oil and perilla seed oil, with maximum interesterification efficiency of 46%. The produced structured lipids belong to the S2U and U2S triacylglycerols, a novel medium-and long-chain triacylglycerol. These results demonstrated that the MPCB-DA-Lipase may be used as an efficient biocatalyst in lipid processing applications of food industries.

Synthesis of symmetrical medium- and long-chain triacylglycerols rich in arachidonic acid at sn-2 position for infant formula

Medium- and long-chain triacylglycerols (MLCT) rich in arachidonic acid (ARA) at sn-2 position were synthesized by a two-step enzymatic method. Firstly, sn-2 monoacylglycerols (MAG) were synthesized at a temperature of 25 °C by enzymatic alcoholysis. The MAG with 69.42% ARA at sn-2 position were obtained by solvent extraction and low temperature solvent crystallization. Secondly, the MLCT rich in ARA at sn-2 position and capric acid (CA) at sn-1,3 positions were produced by enzymatic esterification. Under the optimal conditions (MAG:CA = 1:3 (mol/mol), 0.05 MPa vacuum, 8% Lipozyme RM IM, 5 h, 25 °C), the content of triacylglycerol was up to 93.60%. The triacylglycerol in the form of C10:0-C20:4-C10:0 (including isomers) was about 40.43%. The ARA contents in the total and sn-2 fatty acid composition of the final product were 32.35% and 51.12%, respectively. MLCT rich in ARA at sn-2 position were successfully produced and the product has the potential application for functional food and infant formula.

Chemical transesterification of flaxseed oil and medium‐chain triacylglycerols: MLCT yield, DAG content, physicochemical properties, minor compounds and oxidation stability

SummaryA type of medium‐ and long‐chain triacylglycerols (MLCT) rich in α‐linolenic acid (ALA) was produced by chemical transesterification of medium‐chain triacylglycerols (MCT) and flaxseed oils. Under the optimal substrate conditions of 60%, catalyst loading of 0.3% at 60 °C for 15 min, the product contained MLCT (74.06%), ALA (37.26%) and diacylglycerol (DAG) (11.25%). After that, changes in fatty acid (FA) composition, physicochemical properties and minor compounds after chemical transesterification (CTE) were investigated. The correlations analysis results of these factors on oxidative stability showed these factors could be divided into positive and negative groups. Although DAG appears to be beneficial in slowing down oil oxidation, it is critical to avoid its mass production because it would decrease MLCT.

Medium- and long-chain triacylglycerols composition in preterm and full-term human milk across different lactation stages

Human milk is a natural source of medium-chain fatty acids (MCFAs). It is generally acknowledged that MCFAs exist in medium-chain triacylglycerols (MCTs). However, a previous study revealed that human milk is naturally rich in medium- and long-chain triacylglycerols (MLCTs). Few data are available on the MLCT composition of preterm milk. This study compared the MCFA and MLCT profiles in human milk from mothers after preterm (28–37 weeks) and term (>37 weeks) delivery during three lactational stages. The results showed that almost half of the triacylglycerol species in human milk are MLCT, accounting for approximately 30% of the total TAGs, mainly composed of one MCFA and two long-chain fatty acids, that is, MLL-type MLCT. In addition, MCFAs and MLCTs showed an increase from colostrum to transitional milk, while they were comparable between preterm and full-term milk. This research could help to develop infant formula, which is of great significance for infants.

Medium / long-chain structured triglycerides are superior to physical mixtures triglycerides in Caenorhabditis elegans lifespan through an AMPK modified pathway

Lifespan is a comprehensive indicator of health. Medium and long chain triacylglycerol (MLCT) is an emerging functional product, while there are two types of MLCT (physical mixtures of MCTs and LCTs (MCT/LCT), synthetically structured triglycerides (STG)) with similar fatty acids composition. The two compounds were reported to be associated with some positive benefits in health, while the underlying mechanism is still unclear. Here, it was presented that MCT/LCT could reduce the life span, superoxide dismutase (SOD) activity and catalase (CAT) activity of Caenorhabditis elegans (C. elegans), and increase the total lipid content, the reactive oxygen species (ROS), the MDA and the transcription levels of aak-2, sod-3 and cat-1 when compared with STG group. Further mutant C. elegans experiment proved that the aak-2 pathway is the key for MLCT-modified life span. The different performance of MCT/LCT and STG in life span might result from their inner structure diversity. Overall, our study may have important implications in using specific MLCT to promote healthy aging and designing targeted lipid for individual health.

Synthesis of medium and long-chain triacylglycerols by enzymatic acidolysis of algal oil and lauric acid

To obtain medium and long-chain triacylglycerols (MLCTs) with high levels of lauric acid (LA) and docosahexaenoic acid (DHA), an acidolysis reaction was catalyzed by lipase in a solvent-free system to incorporate LA into algal oil (rich in DHA). Three regiospecific immobilized lipases were compared for their efficiency in the synthesis of MLCTs-riched structured lipids (SLs). The results showed that Lipozyme AOAB8 (from Aspergillus oryzae) displayed the top performance for LA incorporation of MLCTs-riched SLs. The optimum conditions of acidolysis reaction were: reaction temperature 65 °C, substrate mole ratio 1:8 (algal oil to LA), enzyme load 12 g/100 g total substrates, and reaction time of 2.5 h. Under these conditions, LA and DHA of the MLCTs-riched SLs production were 30.91% and 44.68%, respectively, and Lipozyme AOAB8 was reusable for at least 9 times. Melting and crystallization profiles revealed that the MLCTs-riched SLs production possessed preferable physical properties over the original algal oil. The MLCTs-riched SLs can be applied in human milk fat substitutes and dietary supplements as functional lipids.

A comparative study of lipid composition and powder quality among powdered infant formula with novel functional structured lipids and commercial infant formulas

Pancreatic lipase activity and bile salt concentration are very low in infants. Therefore, infant formula (IF) preparation with structured lipids (SLs) containing essential fatty acids and medium-chain fatty acids (MCFAs) with easy absorption features has attracted great attention. In this work, the lipid composition and physiochemical properties of novel SLs enriched with medium- and long-chain triacylglycerols (MLCTs) and their incorporation into a powdered IF compared to commercial IFs were evaluated. The obtained results showed that the SL contains arachidonic (ARA), caprylic, and capric as major fatty acids (FAs). Further, the evaluation of commercial IFs oil showed that oleic, linoleic, palmitic, and lauric were the most abundant FAs. A novel SL possessed highest levels of MCFAs (36.33 ± 1.05%) at sn-1,3 positions and LCUFAs (65.91 ± 1.32%) at the sn-2 position especially ARA (42.82 ± 0.89%). A total of 45, 38, and 25 triacylglycerols molecular species were revealed in a novel SL and commercial IFs available in China and the USA, respectively. Thermoprofile revealed that all IFs oil samples melted below the body temperature. The formula produced with microencapsulated SL and the dry-mixing process showed better optical properties and oxidative stability having lower moisture content. The study has potential applications in the development of IF with improved properties.