Biosynthesis of structured lipids enriched with medium and long-chain triacylglycerols for human milk fat substitute

Preparation of medium- and long-chain triacylglycerols rich in n-3 polyunsaturated fatty acids by bio-imprinted lipase-catalyzed interesterification

Medium and long-chain triacylglycerol (MLCT) rich in n-3 polyunsaturated fatty acids (PUFAs) were obtained in three-hour interesterification of fish oil with medium-chain triacylglycerol (MCTs), using lipase bio-imprinted with surfactant as a catalyst. Initially, for bio-imprinted lipase preparation, the interesterification reaction conditions were optimized, resulting in a lipase with 1.47 times higher catalytic activity compared to control (non-bio-imprinted). Afterwards, the reaction conditions for MLCT synthesis were optimized, using bio-imprinted lipase as a catalyst. The reaction reached equilibrium within first three hours at 70 °C temperature, 4 wt% lipase load, and molar ratio of substrate 1:1.5. Under these conditions, final product contained 18.52% MCT, 56.65% MLCT, and 24.83% long-chain triacylglycerol (LCT). To reduce the MCT content, a solvent extraction process was performed, yielding 2.42% MCT, 56.19% MLCT, and 41.39% LCT. The obtained structured lipids (SLs), enriched in n-3 PUFAs, offer significant health benefits, enhanced bioavailability, with potential applications in functional foods and nutraceuticals.

Recent trends in design of healthier fat replacers: Type, replacement mechanism, sensory evaluation method and consumer acceptance

In recent years, with the increasing awareness of consumers about the relationship between excessive fat intake and chronic diseases, such as obesity, heart disease, diabetes, etc., the demand for low-fat foods has increased year by year. However, a simple reduction of fat content in food will cause changes in physical and chemical properties, physiological properties, and sensory properties of food. Therefore, developing high-quality fat replacers to replace natural fats has become an emerging trend, and it is still a technical challenge to completely simulate the special function of natural fat in low-fat foods. This review aims to provide an overview of development trends of fat replacers, and the different types of fat replacers, the potential fat replacement mechanisms, sensory evaluation methods, and their consumer acceptance are discussed and compared, which may provide a theoretical guidance to produce fat replacers and develop more healthy low-fat products favored by consumers.

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.

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.

Lipase-Catalyzed Synthesis of Structured Fatty Acids Enriched with Medium and Long-Chain n-3 Fatty Acids via Solvent-Free Transesterification of Skipjack Tuna Eyeball Oil and Commercial Butterfat

Human milk lipids generally have the maximum long-chain fatty acids at the sn-2 position of the glycerol backbone. This positioning makes them more digestible than long-chain fatty acids located at the sn-1, 3 positions. These unique fatty acid distributions are not found elsewhere in nature. When lactation is insufficient, infant formula milk has been used as a substitute. However, the distribution of most fatty acids ininfant formula milk is still different from human milk. Therefore, structured lipids were produced by the redistribution of medium-chain fatty acids from commercial butterfat (CBF) and n-3 and n-6 long-chain fatty acids from skipjack tuna eyeball oil (STEO). Redistribution was carried out via transesterification facilitated by Asian seabass liver lipase (ASL-L). Under the optimum conditions including a CBF/STEO ratio (3:1), transesterification time (60 h), and ASL-L unit (250 U), the newly formed modified-STEO (M-STEO) contained 93.56% triacylglycerol (TAG), 0.31% diacylglycerol (DAG), and 0.02% monoacylglycerol (MAG). The incorporated medium-chain fatty acids accounted for 18.2% of M-STEO, whereas ASL-L could incorporate 40% of n-3 fatty acids and 25-30% palmitic acid in M-STEO. The 1H NMRA and 13CNMR results revealed that the major saturated fatty acid (palmitic acid) and unsaturated fatty acids (DHA and EPA) were distributed at the sn-2 position of the TAGs in M-STEO. Thus, M-STEO enriched with medium-chain fatty acids and n-3 fatty acids positioned at the sn-2 position of TAGs can be a potential substitute for human milk fatty acids in infant formula milk (IFM).

Agri-residues and agro-industrial waste substrates bioconversion by fungal cultures to biocatalyst lipase for green chemistry: A review

Huge amounts of agri-residues generated from food crops and processing are discarded in landfills, causing environmental problems. There is an urgent need to manage them with a green technological approach. Agri-residues are rich in nutrients such as proteins, lipids, sugars, minerals etc., and provide an opportunity for bioconversion into value-added products. Considering the importance of lipase as a biocatalyst for various industrial applications and its growing need for economic production, a detailed review of bioconversion of agri-residues and agro-industrial substrate for the production of lipase from fungal species from a technological perspective has been reported for the first time. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram was used for the identification and selection of articles from ScienceDirect, Google Scholar, and Scopus databases from 2010 to 2023 (July), and 108 peer-reviewed journal articles were included based on the scope of the study. The composition of agri-residues/agro-industrial wastes, fungal species, lipase production, industrial/green chemistry applications, and the economic impact of using agri-residues on lipase costs have been discussed. Bioconversion procedure, process developments, and technology gaps required to be addressed before commercialization have also been discussed. This process expects to decrease the environmental pollution from wastes, and low-cost lipase can help in the growth of the bioeconomy.

Isolation of Fatty Acids from the Enzymatic Hydrolysis of Capsaicinoids and Their Use in Enzymatic Acidolysis of Coconut Oil

Herein we report the optimization of enzymatic hydrolysis of a mixture of capsaicinoids, capsaicin and dihydrocapsaicin obtained from chili peppers, and the utilization of the isolated fatty acids for the modification of coconut oil using enzyme catalyzed acidolysis. This work was carried out as the fatty acids that can be isolated from capsaicinoid hydrolysis have been shown to possess interesting biological properties. These biological properties could be better exploited by incorporating the fatty acids into a suitable delivery vehicle. The enzymatic hydrolysis of the mixture of capsaicin and dihydrocapsaicin was carried out using Novozym® 435 in phosphate buffer (pH 7.0) at 50℃. The enzyme catalyst could be reused in multiple cycles of the hydrolysis reaction. The desired 8-methyl-6-trans-nonenoic acid and 8-methylnonanoic acid were isolated from the hydrolysis reaction mixture using a simple extraction procedure with a 47.8% yield. This was carried out by first extracting the reaction mixture at pH 10 with ethyl acetate to remove any dissolved capsaicinoids and vanillyl amine side product. The fatty acids were isolated after adjustment of the pH of the reaction mixture to 5 and second extraction with ethyl acetate. The acidolysis of coconut oil with the obtained fatty acids was performed using Lipozyme® TL IM. The performance of the acidolysis reaction was evaluated using 1H-NMR spectroscopy and verified in selected cases using gas chromatography. The best performing conditions involved carrying out the acidolysis reaction at 60℃ with a 1.2 w/w ratio of the fatty acids to coconut oil and 10% enzyme loading for 72 h. This resulted in the incorporation of 26.61% and 9.86% of 8-methyl-6-trans-nonenoic acid and 8-methylnonanoic acid, respectively, into the modified coconut oil product. This product can act as a potential delivery vehicle for these interesting compounds.

Dispersive liquid‒liquid microextraction combined with enzyme-linked immunosorbent assay for the analysis of chlorpyrifos in cereal samples

In this paper, an analysis method for chlorpyrifos (CPF) in cereal samples was proposed using dispersive liquid‒liquid microextraction combined with an enzyme-linked immunosorbent assay. In the dispersive liquid‒liquid microextraction, deep eutectic solvents and fatty acids were used as solvents to extract, purify, and concentrate CPF in cereals. In the enzyme-linked immunosorbent assay, gold nanoparticles were utilized to enrich and conjugate more antibodies and horseradish peroxidase, while magnetic beads were used as solid supports to amplify the signal and shorten the detection time of CPF. The linearity range was 0.002-1 μg kg-1, and the limit of detection was 0.0006 μg kg-1. The extraction recoveries were 86.7-99.9% with a relative standard deviation of less than 7.0%. The proposed method was successfully used to analyze CPF in cereal samples (rice, wheat, maize, and millet) and has prospects for the pretreatment and detection of CPF residues in other food samples.

Novel trends and challenges in fat modification of next-generation infant formula: Considering the structure of milk fat globules to improve lipid digestion and metabolism of infants

Differences in the composition and structure of lipid droplets in infant formula (IF) and human milk (HM) can affect the fat digestion of infants, leading to high risk of metabolic diseases during later stages of growth. Recently, interest in simulating HM fat (HMF) has gradually increased due to its beneficial functions for infants. Much research focuses on the simulation of fatty acids and triacylglycerols. Enzymatic combined with new technologies such as carbodiimide coupling immobilization enzymes, solvent-free synthesis, and microbial fermentation can improve the yield of simulated HMF. Furthermore, fat modification in next-generation IF requires attention to the impact on the structure and function of milk fat globules (MFG). This review also summarizes the latest reports on MFG structure simulation, mainly related to the addition method and sequence of membrane components, and other milk processing steps. Although some of the simulated HMF technologies and products have been applied to currently commercially available IF, the cost is still high. Furthermore, understanding the fat decomposition of simulated HMF during digestion and assessing its nutritional effects on infants later in life is also a huge challenge. New process development and more clinical studies are needed to construct and evaluate simulated HMF in the future.

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

BACKGROUND

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).

RESULTS

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.

CONCLUSION

Eicosapentaenoic acid-enriched MLCT was developed. This may provide a novel strategy for clinical nutritional intervention. © 2023 Society of Chemical Industry.

Trends in Fat Modifications Enabling Alternative Partially Hydrogenated Fat Products Proposed for Advanced Application

The natural properties of oils and fats do not always allow for their direct use in industry (e.g., for food, cosmetics, and pharmaceuticals). Furthermore, such raw materials are often too expensive. Nowadays, the requirements for the quality and safety of fat products are increasing. For this reason, oils and fats are subjected to various modifications that make it possible to obtain a product with the desired characteristics and good quality that meets the needs of product buyers and technologists. The modification techniques of oils and fats change their physical (e.g., raise the melting point) and chemical properties (e.g., fatty acid composition). Conventional fat modification methods (hydrogenation, fractionation, and chemical interesterification) do not always meet the expectations of consumers, nutritionists, and technologists. In particular, Hydrogenation, while it allows us to obtain delicious products from the point of view of technology, is criticised for nutritional reasons. During the partial hydrogenation process, trans-isomers (TFA), dangerous for health, are formed. One of the modifications that meets current environmental requirements and trends in product safety and sustainable production is the enzymatic interesterification of fats. The unquestionable advantages of this process are the wide spectrum of possibilities for designing the product and its functional properties. After the interesterification process, the biologically active fatty acids in the fatty raw materials remain intact. However, this method is associated with high production costs. Oleogelation is a novel method of structuring liquid oils with small oil-gelling substances (even 1%). Based on the type of oleogelator, the methods of preparation can differ. Most oleogels of low molecular weight (waxes, monoglycerides, and sterols) and ethyl cellulose are prepared by dispersion in heated oil, while oleogels of high molecular weight require dehydration of the emulsion system or solvent exchange. This technique does not change the chemical composition of the oils, which allows them to keep their nutritional value. The properties of oleogels can be designed according to technological needs. Therefore, oleogelation is a future-proof solution that can reduce the consumption of TFA and saturated fatty acids while enriching the diet with unsaturated fatty acids. Oleogels can be named "fats of the future" as a new and healthy alternative for partially hydrogenated fats in foods.

The structure of triglycerides impacts the digestibility and bioaccessibility of nutritional lipids during in vitro simulated digestion

The triglyceride (TAG) structure of lipids may affect their nutritional properties by affecting the process of digestion and absorption. In this paper, a mixture of medium-chain triglycerides and long-chain triglycerides (PM) and medium- and long-chain triglycerides (MLCT) were selected to explore the effects of triglyceride structure on in vitro digestion and bioaccessibility. The results showed that MLCT released more free fatty acids (FFAs) than PM (99.88% vs 92.82%, P < 0.05). The first-order rate constant for FFA release from MLCT was lower than that for PM (0.0395 vs 0.0444 s^-1, P < 0.05), which suggests that the rates of PM digestion were faster than those of MLCT. Our results demonstrated that DHA and EPA were more bioaccessible from MLCT than from PM. These results highlighted the important role of TAG structure in regulation of lipid digestibility and bioaccessibility.

Progress and perspectives of enzymatic preparation of human milk fat substitutes

Human milk fat substitutes (HMFS) with triacylglycerol profiles highly similar to those of human milk fat (HMF) play a crucial role in ensuring the supply in infant nutrition. The synthesis of HMFS as the source of lipids in infant formula has been drawing increasing interest in recent years, since the rate of breastfeeding is getting lower. Due to the mild reaction conditions and the exceptionally high selectivity of enzymes, lipase-mediated HMFS preparation is preferred over chemical catalysis especially for the production of lipids with desired nutritional and functional properties. In this article, recent researches regarding enzymatic production of HMFS are reviewed and specific attention is paid to different enzymatic synthetic route, such as one-step strategy, two-step catalysis and multi-step processes. The key factors influencing enzymatic preparation of HMFS including the specificities of lipase, acyl migration as well as solvent and water activity are presented. This review also highlights the challenges and opportunities for further development of HMFS through enzyme-mediated acylation reactions.

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.

Future of Structured Lipids: Enzymatic Synthesis and Their New Applications in Food Systems

Structured lipids (SLs) refer to a new type of functional lipid obtained by modifying natural triacylglycerol (TAG) through the restructuring of fatty acids, thereby altering the composition, structure, and distribution of fatty acids attached to the glycerol backbones. Due to the unique functional characteristics of SLs (easy to absorb, low in calories, reduced serum TAG, etc.), there is increasing interest in the research and application of SLs. SLs were initially prepared using chemical methods. With the wide application of enzymes in industries and the advantages of enzymatic synthesis (mild reaction conditions, high catalytic efficiency, environmental friendliness, etc.), synthesis of SLs using lipase has aroused great interest. This review summarizes the reaction system of SL production and introduces the enzymatic synthesis and application of some of the latest SLs discussed/developed in recent years, including medium- to long-chain triacylglycerol (MLCT), diacylglycerol (DAG), EPA- and DHA-enriched TAG, human milk fat substitutes, and esterified propoxylated glycerol (EPG). Lastly, several new ways of applying SLs (powdered oil, DAG plastic fat, inert gas spray oil, and emulsion) in the future food industry are also highlighted.

Ultrasound enhanced butyric acid-lauric acid designer lipid synthesis: Based on artificial neural network and changes in enzymatic structure

Ultrasound is a green technology for intensifying enzymatic reactions. In this study, an ultrasonic water bath with equipment parameters of 28 kHz, 1750.1 W/m², 60% duty cycle was used to assist the synthesis of butyric acid-lauric acid designer lipid (BLDL), which was catalyzed by Lipozyme 435. A convincing three-layer feed-forward artificial neural network (ANN) model was established (R² = 0.949, RMSE = 4.759, ADD = 7.329) to accurately predict the optimal parameters combination, which was described as 13.72 mL reaction volume, 15.49% enzyme loading, 0.253 substrate molar ratio (tributyrin/lauric acid), 56.58 °C reaction temperature and 120 min reaction time. The ultrasonic assistance increased actual butyric acid conversion rate by 11.38%, and also enhanced the consumption rate of tributyrin and lauric acid during the reaction. Meanwhile, the esterification activity of Lipozyme 435 was enhanced and its effectiveness up to 6 cycles. Structurally, ultrasound assistance significantly disrupted the secondary structure of the Lipozyme 435: reduced the content of α-helices, increased the content of β-sheet and β-turn. In addition, sonication caused an increase in crevice and micro-damage on the surface of the immobilized enzyme. In conclusion, low-intensity ultrasound at 28 kHz improved the synthesis efficiency of BLDL, which was scientifically predicted by ANN model, and the change of enzyme structure may be the vital reason for ultrasound enhanced reaction. However, the effect of ultrasound on immobilized enzymes' activity needs to be further explored.

Advances in analysis, metabolism and mimicking of human milk lipids

Human milk lipids differ from the milk lipids of other mammals in composition and positional distribution of fatty acids. Analysis and detection technology of lipids is key to understanding milk lipids, and thus the concentrations, compositions and distribution characteristics of milk lipids are discussed. Differences between human milk lipids and their substitutes in form, composition and structure affect their digestion, absorption and function in infants. Characteristics and mimicking of human milk lipids have been intensively studied with the objective of narrowing the gap between human milk and infant formulae. Based on the existing achievements, further progress may be made by improving detection techniques, deepening knowledge of metabolic pathways and perfecting fat substitutes. This review detailed the characteristics of human milk lipids and related detection technologies with a view towards providing a clear direction for research on mimicking human milk lipids in formulae to further improve infant nutrition.

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.

The enzymatic synthesis of EPA-rich medium- and long-chain triacylglycerol improves the digestion behavior of MCFA and EPA: evidence on in vitro digestion

Medium-chain triglyceride (MCT) and eicosapentaenoic acid (EPA) have been widely applied in nutritional supplementation. However, when administered individually or mixed, they were unable to maximize their nutritional value. Hence, EPA-rich medium- and long-chain triacylglycerol (MLCT) was synthesized from MCT and EPA-rich fish oil (FO) by enzymatic transesterification. The fatty acids in triglyceride (TAG) were rearranged which resulted in significant changes in TAG profiles compared to the physical mixture of MCT and FO (PM). EPA-containing MML (MML, MLM and LMM) and LLM (LLM, LML and MLL) type TAGs account for 70.21%. The fate of different oils (MCT, FO, PM, and MLCT) across the gastrointestinal tract was subsequently simulated using an in vitro digestion model. The results showed that the physical and structural characteristics of different oils during digestion depended upon the oil type and the microenvironment they were in. After 120 min of small intestine digestion, the degree of hydrolysis for MLCT was higher than that for the other three oils. The final FFA release level was in the following order: MLCT (102.79%) > MCT (95.20%) > PM (85.81%) > FO (74.18%). This can be attributed to the composition and positional distribution of fatty acids in TAGs. What's more, LCFAs (EPA) in MLCT mainly existed in the form of sn-2 MAG, which was conducive to their subsequent absorption and transport. These results may aid in the future rational design of structural lipids, thereby regulating lipid digestion and maximizing the nutritional value of oils.

Tailoring the Structure of Lipids, Oleogels and Fat Replacers by Different Approaches for Solving the Trans-Fat Issue-A Review

The issue of the adverse effects of trans-fatty acids has become more transparent in recent years due to researched evidence of their link with coronary diseases, obesity or type 2 diabetes. Apart from conventional techniques for lipid structuring, novel nonconventional approaches for the same matter, such as enzymatic interesterification, genetic modification, oleogelation or using components from nonlipid origins such as fat replacers have been proposed, leading to a product with a healthier nutritional profile (low in saturated fats, zero trans fats and high in polyunsaturated fats). However, replacing conventional fat with a structured lipid or with a fat mimetic can alternate some of the technological operations or the food quality impeding consumers' acceptance. In this review, we summarize the research of the different existing methods (including conventional and nonconventional) for tailoring lipids in order to give a concise and critical overview in the field. Specifically, raw materials, methods for their production and the potential of food application, together with the properties of new product formulations, have been discussed. Future perspectives, such as the possibility of bioengineering approaches and the valorization of industrial side streams in the framework of Green Production and Circular Economy in the production of tailored lipids, have been highlighted. Additionally, a schematic diagram classifying conventional and nonconventional techniques is proposed based on the processing steps included in tailored lipid production as a convenient and straightforward tool for research and industry searching for healthy, sustainable and zero trans edible lipid system alternatives.

Medium chain triglyceride and medium-and long chain triglyceride: metabolism, production, health impacts and its applications - a review

Structured lipid is a type of modified form of lipid that is "fabricated" with the purpose to improve the nutritional and functional properties of conventional fats and oils derived from animal and plant sources. Such healthier choice of lipid received escalating attention from the public for its capability to manage the rising prevalence of metabolic syndrome. Of which, medium-chain triacylglycerol (MCT) and medium-and long-chain triacylglycerol (MLCT) are the few examples of the "new generation" custom-made healthful lipids which are mainly composed of medium chain fatty acid (MCFA). MCT is made up exclusively of MCFA whereas MLCT contains a mixture of MCFA and long chain fatty acid (LCFA), respectively. Attributed by the unique metabolism of MCFA which is rapidly metabolized by the body, MCFA and MCT showed to acquire multiple physiological and functional properties in managing and reversing certain health disorders. Several chemically or enzymatically oils and fats modification processes catalyzed by a biological or chemical catalyst such as acidolysis, interesterification and esterification are adopted to synthesis MCT and MLCT. With their purported health benefits, MCT and MLCT are widely being used as nutraceutical in food and pharmaceutical sectors. This article aims to provide a comprehensive review on MCT and MLCT, with an emphasis on the basic understanding of its structures, properties, unique metabolism; the current status of the touted health benefits; latest routes of production; its up-to-date applications in the different food systems; relevant patents filed and its drawbacks.

Efficient Synthesis of Structured Phospholipids Containing Short-Chain Fatty Acids over a Sulfonated Zn-SBA-15 Catalyst

Catalytic production of structured phospholipids (SPLs) containing short-chain fatty acids (SCFAs) in an efficient heterogeneous manner is of great importance from the standpoint of food engineering. Herein, a bifunctionalized sulfonated Zn-SBA-15 catalyst was studied for SPL synthesis through interesterification of soybean lecithin with ethyl propionate or methyl butyrate. Various characterization techniques such as pyridine Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy were conducted to determine the physicochemical properties, so as to build the possible structure-reactivity relationship of the catalyst. In screening tests with commercial Amberlyst-15 or other SBA-15-type materials, the as-prepared sample showed promising catalytic performance probably owing to its mesoporous structure and cooperative role of Brönsted and Lewis acid sites. Notably, the sample was easily separated and recycled without obvious deactivation. In general, the investigated catalyst was regarded as one of the promising alternatives to otherwise expensive biocatalysts for SCFA-containing SPL production.

Lipase catalysis of α-linolenic acid-rich medium- and long-chain triacylglycerols from perilla oil and medium-chain triacylglycerols with reduced by-products

BACKGROUND

Medium- and long- chain triacylglycerols (MLCTs) are functional structural lipids that can provide the human body with essential fatty acids and a faster energy supply. This study aimed to prepare MLCTs rich in α-linolenic by enzymatic interesterification of perilla oil and medium-chain triacylglycerols (MCTs), catalyzed by Lipozyme RM IM, Lipozyme TL IM, Lipozyme 435, and Novozyme 435 respectively.

RESULTS

The effects of lipase loading, concentration of MCTs, reaction temperature, and reaction time on the yield of MLCTs were investigated. It was found that the reaction achieved more than a 70% yield of MLCTs in triacylglycerols under the conditions of 400 g kg^-1 MCTs and 60 g kg^-1 lipase loading after equilibrium. A novel two-stage deodorization was also applied to purify the interesterification products. The triacylglycerols reach over 97% purity in the products with significant removal (P < 0.05) of the free fatty acids, and the trans fatty acids were strictly controlled at below 1%. There was more than 40% α-linolenic in the purified products, with long-chain fatty acids mostly occupying the desired sn-2 position in acylglycerols, which are more active in hydrolysis.

CONCLUSION

A series of novel α-linolenic acid-rich medium- and long-chain triacylglycerols was prepared. Under appropriate reaction conditions, the yield of MLCTs in triacylglycerols was above 70%. A novel two-stage deodorization can be used to promote the elimination of free fatty acids and limit the generation of trans fatty acids. © 2020 Society of Chemical Industry.