Synthesis, physicochemical properties, and health aspects of structured lipids: A review

Could New Palm-Free Structured Lipids Mitigate Postprandial Hyperlipidemia and Inflammation Induced by High-Fat Meals in Swiss Mice?

A high-fat meal can cause postprandial hyperlipemia, initiating an acute inflammatory response. New structured lipids (SLs) free from trans and palm fatty acids are emerging as food structurants.

Objective: We evaluated the postprandial response and inflammatory profiles in Swiss mice after oral administration of SLs in high-fat meals.

Methods: SLs with different contents of long-chain saturated fatty acids were synthesized through an interesterification process involving soybean, peanut oils and crambe hard fat.

Results: SLs containing 23.79% (SL1), 32.01% (SL2), and 43.87% (SL3) of total saturated fatty acids reduced the absorption of serum triglycerides and appeared to mitigate postprandial inflammation by interleukin-6. A faster gastric emptying rate after consuming SL3 was corroborated by the fecal presence of behenic acid.

Conclusions: Our results suggest that SLs, free from palm and trans fats, may have the potential to mitigate inflammation, reduce the postprandial response, and lower absorption upon acute consumption.

A review on preparation and application of low-calorie structured lipids in food system

Low-calorie structured lipids are an advanced form of functional lipids made by changing the position of fatty acids attached to the glycerol backbone. The main reason for their production is to get nutraceutical lipids. Different methods are used to synthesize low-calorie structured lipids, like chemical or enzymatic methods. Initially, these lipids are prepared by using chemical methods. Synthesis of low-calorie structured lipids using enzymes is now in demand due to several advantages like good catalytic efficiency, environmentally friendly, and moderate reaction conditions. Enzymatic interesterification is mostly used in industries to make modified lipids like low-calorie structured lipids, human milk substitutes, cocoa butter equivalents, margarine, and shortenings. This review summarizes the synthesis, uses and clinical applications of modified lipids in food systems.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01689-8.

Lauric-α-linolenic lipids modulate gut microbiota, preventing obesity, insulin resistance and inflammation in high-fat diet mice

Medium- and long-chain triacylglycerols (MLCTs) are regarded as healthy premium oils; however, the health benefits of novel MLCTs enriched with lauric and α-linolenic acids are still not fully understood. This study examined the health benefits of lauric-α-linolenic structural lipids (ALSL) and physical mixture (PM) with a similar fatty acid composition in mice with obesity induced by the high-fat diet (HFD). The data indicated that ALSL is more effective than PM in counteracting obesity, insulin resistance, hyperlipidaemia, liver injury, and systemic inflammation in HFD-induced mice. These effects may be associated with the regulation of gut microbiota. ALSL significantly upregulated the abundance of Dubosiella, Lactobacillus, and Bifidobacterium while reducing the abundance of Ileibacterium. Furthermore, ALSL therapy increased the levels of acetic acid, propionic acid, and total short-chain fatty acids. Correlation analysis found that the positive changes in these gut microbes correlated positively with the anti-inflammatory, insulin-sensitizing, and anti-obesity effects of ALSL.

Recent insight into the advances and prospects of microbial lipases and their potential applications in industry

Enzymes play a crucial role in various industrial sectors. These biocatalysts not only ensure sustainability and safety but also enhance process efficiency through their unique specificity. Lipases possess versatility as biocatalysts and find utilization in diverse bioconversion reactions. Presently, microbial lipases are gaining significant focus owing to the rapid progress in enzyme technology and their widespread implementation in multiple industrial procedures. This updated review presents new knowledge about various origins of microbial lipases, such as fungi, bacteria, and yeast. It highlights both the traditional and modern purification methods, including precipitation and chromatographic separation, the immunopurification technique, the reversed micellar system, the aqueous two-phase system (ATPS), and aqueous two-phase flotation (ATPF), moreover, delves into the diverse applications of microbial lipases across several industries, such as food, vitamin esters, textile, detergent, biodiesel, and bioremediation. Furthermore, the present research unveils the obstacles encountered in employing lipase, the patterns observed in lipase engineering, and the application of CRISPR/Cas genome editing technology for altering the genes responsible for lipase production. Additionally, the immobilization of microorganisms' lipases onto various carriers also contributes to enhancing the effectiveness and efficiencies of lipases in terms of their catalytic activities. This is achieved by boosting their resilience to heat and ionic conditions (such as inorganic solvents, high-level pH, and temperature). The process also facilitates the ease of recycling them and enables a more concentrated deposition of the enzyme onto the supporting material. Consequently, these characteristics have demonstrated their suitability for application as biocatalysts in diverse industries.

Structured Triacylglycerol with Optimal Arachidonic Acid and Docosahexaenoic Acid Content for Infant Formula Development: A Bio-Accessibility Study

Polyunsaturated fatty acids (PUFAs), especially arachidonic acid (ARA) and docosahexaenoic acid (DHA), are extremely important fatty acids for brain development in the fetus and early childhood. Premature infants face challenges obtaining these two fatty acids from their mothers. It has been reported that supplementation with triacylglycerols (TAGs) with an ARA:DHA (w/w) ratio of 2:1 may be optimal for preterm infants, as presented in commercial formulas such as Formulaid™. This study explored methods to produce TAGs with a 2:1 ratio (ARA:DHA), particularly at the more bioavailable sn-2 position of the glycerol backbone. Blending and enzymatic acidolysis of microalgae oil (rich in DHA) and ARA-rich oil yielded products with the desired ARA:DHA ratio, enhancing sn-2 composition compared to Formulaid™ (1.6 for blending and 2.3 for acidolysis versus 0.9 in Formulaid™). Optimal acidolysis conditions were 45 °C, a 1:3 substrate molar ratio, 10% Candida antarctica lipase, and 4 h. The process was reproducible, and scalable, and the lipase could be reused. In vitro digestion showed that 75.5% of the final product mixture was bio-accessible, comprising 19.1% monoacylglycerols, ~50% free fatty acids, 14.6% TAGs, and 10.1% diacylglycerols, indicating better bio-accessibility than precursor oils.

Structuration of lipid bases zero-trans and palm oil-free for food applications

This work evaluated structured lipids (SLs) through chemical and enzymatic interesterification (CSLs and ESLs). Blends of soybean oil and peanut oil 1:1 wt% were used, with gradual addition of fully hydrogenated crambe to obtain a final behenic acid concentration of 6, 12, 18, and 24 %. Chemical catalysis used sodium methoxide (0.4 wt%) at 100 °C for 30 min, while enzymatic catalysis used Lipozyme TL IM (5 wt%) at 60 °C for 6 h. Major fatty acids identified were C16:0, C18:0, and C22:0. It was observed that with gradual increase of hard fat, the CSLs showed high concentrations of reaction intermediates, indicating further a steric hindrance, unlike ESLs. Increased hard fat also altered crystallization profile and triacylglycerols composition and ESLs showed lower solid fat, unlike CSLs. Both methods effectively produced SLs as an alternative to trans and palm fats, view to potential future applications in food products.

Structuring vegetable oils through enzymatic glycerolysis for water-in-oil emulsions

Enzymatic glycerolysis is a biotechnological process for structuring vegetable oils. This study investigates the kinetics of glycerolysis of peanut oil and explores the potential of the resulting structured oil to enhance the physical stability of water-in-oil emulsions. Using a 1:1 glycerol-to-oil molar ratio and 4 % lipase B from Candida antarctica as a catalyst, the reaction was conducted at 65 °C with stirring at 400 rpm. Acylglyceride fractions changes were quantified through NMR and DSC. Fat crystal formation was observed using scanning electron microscopy. The results revealed a first-order decay pattern, converting triglycerides into monoacylglycerides and diacylglycerides in less than 16 h. Subsequently, water-in-oil emulsions prepared with glycerolized oil showed augmented stability through multiple light scattering techniques and visual assessment. The structured oils effectively delayed phase separation, highlighting the potential of glycerolysis in developing vegetable oil-based emulsions with improved functional properties and reduced saturated fatty acid content.

Structural and functional insights into the enzymatic activities of lipases from Burkholderia stagnalis and Burkholderia plantarii

Lipases with high interesterification activity are important enzymes for industrial use. The lipase from Burkholderia stagnalis (BsL) exhibits higher interesterification activity than that from Burkholderia plantarii (BpL) despite their significant sequence similarity. In this study, we determined the crystal structure of BsL at 1.40 Å resolution. Utilizing structural insights, we have successfully augmented the interesterification activity of BpL by over twofold. This enhancement was achieved by substituting threonine with serine at position 289 through forming an expansive space in the substrate-binding site. Additionally, we discuss the activity mechanism based on the kinetic parameters. Our study sheds light on the structural determinants of the interesterification activity of lipase.

Enzymatic Preparation, In-Depth Molecular Analysis, and In Vitro Digestion Simulation of Palmitoleic Acid (ω-7)-Enriched Fish Oil Triacylglycerols

In this study, an enzymatic reaction was developed for synthesizing pure triacylglycerols (TAG) with a high content of palmitoleic acid (POA) using fish byproduct oil. The characteristics of synthesized structural TAGs rich in POA (POA-TAG) were analyzed in detail through ultrahigh-performance liquid chromatography Q Exactive orbitrap mass spectrometry. Optimal conditions were thoroughly investigated and determined for reaction systems, including the use of Lipozyme TL IM and Novozym 435, 15 wt % lipase loading, substrate mass ratio of 1:3, and water content of 2.5 and 0.5 wt %, respectively, resulting in yields of 67.50 and 67.45% for POA-TAG, respectively. Multivariate statistical analysis revealed that TAG 16:1/16:1/20:4, TAG 16:1/16:1/16:1, TAG 16:1/16:1/18:1, and TAG 16:0/16:1/18:1 were the main variables in Lipozyme TL IM and Novozym 435 enzyme-catalyzed products under different water content conditions. Finally, the fate of POA-TAG across the gastrointestinal tract was simulated using an in vitro digestion model. The results showed that the maximum release of free fatty acids and apparent rate constants were 71.44% and 0.0347 s-1, respectively, for POA-TAG lipids, and the physical and structural characteristics during digestion depended on their microenvironments. These findings provide a theoretical basis for studying the rational design of POA-structural lipids and exploring the nutritional and functional benefits of POA products.

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

BACKGROUND

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.

RESULTS

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.

CONCLUSION

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.

Potential application of bee products in food industry: An exploratory review

Over the past eight years, bee products such as wax, honey, propolis, and pollen have generated intense curiosity about their potential food uses; to explore these possibilities, this review examines the nutritional benefits and notable characteristics of each product related to the food industry. While all offer distinct advantages, there are challenges to overcome, including the risk of honey contamination. Indeed, honey has excellent potential as a healthier alternative to sugar, while propolis's remarkable antibacterial and antioxidant properties can be enhanced through microencapsulation. Pollen is a versatile food with multiple applications in various products. In addition, the addition of beeswax to oleogels and its use as a coating demonstrate significant improvements in the quality and preservation of environmentally sustainable foods over time. This study demonstrates that bee products and apitherapy are essential for sustainable future food and innovative medical treatments.

Enzymatic interesterification improves the lipid composition, physicochemical properties and rheological behavior of Cinnamomum camphora seed kernel oil, Pangasius bocourti stearin and perilla seed oil blends

The study aimed to investigate the effect of enzymatic interesterification on the lipid composition, physicochemical properties and rheological behavior of Cinnamomum camphora seed kernel oil (CCSKO), Pangasius bocourti stearin (PBST) and perilla seed oil (PSO) blends. The results showed that the interesterification process significantly changed the TAG profile of the blends. Lipid products from the enzymatic interesterification (EIE) had significantly lower slide melting point and solid fat content than the non-interesterification (NIE) lipid products. Interesterification process changed the crystal polymorphic forms from β > β' of NIE to β < β' of EIE. The crystal morphology of EIE was smaller and more diffuse compared to the NIE. Moreover, EIE showed improved rheological behavior, which was more suitable for food margarine preparation. The findings have provided a theoretical basis for the potential application of Lipozyme TL IM modified lipid products in the food industry.

Solvent-Free Enzymatic Synthesis of Dietary Triacylglycerols from Cottonseed Oil in a Fluidized Bed Reactor

The synthesis of structured lipids with nutraceutical applications, such as medium-long-medium (MLM) triacylglycerols, via modification of oils and fats represents a challenge for the food industry. This study aimed to synthesize MLM-type dietary triacylglycerols by enzymatic acidolysis of cottonseed oil and capric acid (C10) catalyzed by Lipozyme RM IM (lipase from Rhizomucor miehei) in a fluidized bed reactor (FBR). After chemical characterization of the feedstock and hydrodynamic characterization of the reactor, a 2² central composite rotatable design was used to optimize capric acid incorporation. The independent variables were cycle number (20-70) and cottonseed oil/capric acid molar ratio (1:2-1:4). The temperature was set at 45 °C. The best conditions, namely a 1:4 oil/acid molar ratio and 80 cycles (17.34 h), provided a degree of incorporation of about 40 mol%, as shown by compositional analysis of the modified oil. Lipozyme RM IM showed good operational stability (k_d = 2.72 × 10^-4 h^-1, t_1/2 = 2545.78 h), confirming the good reuse capacity of the enzyme in the acidolysis of cottonseed oil with capric acid. It is concluded that an FBR configuration is a promising alternative for the enzymatic synthesis of MLM triacylglycerols.

Influence of 1,3-diacylglycerol on physicochemical and digestion properties of nanoemulsions and its enhancement of encapsulation and bioaccessibility of hydrophobic nobiletin

Lipid-based delivery systems are commonly used to encapsulate hydrophobic bioactive compounds for enhancing their bioaccessibility and bioavailability, especially for triacylglycerol (TAG) oil-based delivery systems. However, studies on the development of 1,3-diacylglycerol (DAG) oil-based delivery systems are rather limited. Herein, the influence of 1,3-DAG oil as a carrier oil on the properties of nanoemulsions and the bioaccessibility of encapsulated hydrophobic nobiletin (NOB) were investigated. High-purity 1,3-DAG (over 93% pure) was prepared by a combination of enzymatic esterification and ethanol crystallization. 1,3-DAG oil as a carrier oil could be used to formulate nanoemulsions with smaller droplet size, narrower size distribution and similar stability compared to TAG oil. Importantly, 1,3-DAG oil could efficiently encapsulate high-loading NOB (1.45 mg g-1) in nanoemulsions and significantly improve the bioaccessibility of NOB (above 80%), which is attributable to its massive lipolysis and higher encapsulation capacity than TAG oil. Moreover, the addition of the 1,3-DAG component in TAG oil significantly improved the properties of nanoemulsions and the loading and bioaccessibility of NOB, especially as the 1,3-DAG content was not less than 50%. The structure of lipids (DAG versus TAG) influenced the nanoemulsion properties and the bioaccessibility of encapsulated NOB. Based on the good properties of 1,3-DAG oil coupled with its health benefits, 1,3-DAG oil-based nanoemulsion delivery systems have great prospects for improving and extending emulsion properties and bioactivity as well as bioaccessibility enhancement.

pH-shift strategy improving the thermal stability and oxidation stability of rice starch/casein-based high internal phase emulsions for the application in fish cake

The thermal stability of the different pH-shift rice starch/casein-based high internal phase emulsions (SC-HIPE) were evaluated in the present study to verify potential in improving the quality of fish cake. The results showed that the pH-shift treatment improved thermal stability (from 27.23% to 76.33%) and oxidation time (from 5.01 h to 6.86 h) of SC-HIPE, which showed the smaller droplet size (decreased from 15.14 to 1.64 μm) and higher storage module. The breaking force of FC with thermal stable SC-HIPE (average 64.95 g) was higher than that with thermal unstable SC-HIPE (51.05 g). The cohesiveness, adhesiveness and chewiness could be improved by adding thermal stable SC-HIPE, compared with pork fat. Additionally, combining sensory evaluation, the thermal stable SC-HIPE improved the gel quality, thus it could be completely replaced pork fat in the preparation of FC, which provided theoretical guidance for the preparation and application of fat substitutes.

Recent Advances in the Microencapsulation of Essential Oils, Lipids, and Compound Lipids through Spray Drying: A Review

In recent decades, the microcapsules of lipids, compound lipids, and essential oils, have found numerous potential practical applications in food, textiles, agricultural products, as well as pharmaceuticals. This article discusses the encapsulation of fat-soluble vitamins, essential oils, polyunsaturated fatty acids, and structured lipids. Consequently, the compiled information establishes the criteria to better select encapsulating agents as well as combinations of encapsulating agents best suited to the types of active ingredient to be encapsulated. This review shows a trend towards applications in food and pharmacology as well as the increase in research related to microencapsulation by the spray drying of vitamins A and E, as well as fish oil, thanks to its contribution of omega 3 and omega 6. There is also an increase in articles in which spray drying is combined with other encapsulation techniques, or modifications to the conventional spray drying system.

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.

Effect of Structured Phenolic Lipids with EPA/DHA and Gallic Acid against Metabolic-Associated Fatty Liver Disease (MAFLD) in Mice

Obesity is the leading risk factor for developing metabolic (dysfunction)-associated fatty liver disease (MAFLD). The food industry has an essential role in searching for new strategies to improve primary food sources to revert some of the metabolic alterations induced by obesity. There is consistent evidence that long-chain polyunsaturated fatty acids (n-3 LCPUFA) belonging to the n-3 series, i.e., eicosapentaenoic (20:5n-3, EPA) and docosahexaenoic (22:6n-3, DHA) acids, could revert some alterations associated with obesity-induced metabolic diseases. A relevant tool is the synthesis of structured acylglycerols (sAG), which include EPA or DHA at the sn-2 position. On the other hand, it has been reported that a crucial role of antioxidants is the reversion of MAFLD. In this work, we studied the effects of new molecules incorporating gallic acid (GA) into EPA/DHA-rich structured lipids. Mice were fed with a high-fat diet (60%) for three months and were then divided into five groups for supplementation with sAG and sAG structured with gallic acid (structured phenolic acylglycerols, sPAG). sPAG synthesis was optimized using a 2²-screening factorial design based on the response surface methodology (RSM). Our results show that treatment of sPAG was effective in decreasing visceral fat, fasting glycemia, fasting insulin, suggesting that this new molecule has a potential use in the reversal of MAFLD-associated alterations.

Recent Advances in Lipases and Their Applications in the Food and Nutraceutical Industry

Lipases are efficient enzymes with promising applications in the nutraceutical and food industry, as they can offer high yields, pure products under achievable reaction conditions, and are an environmentally friendly option. This review addresses the production of high-value-added compounds such as fatty acid esters, with the potential to be used as flavoring agents or antioxidant and antimicrobial agents, as well as structured lipids that offer specific functional properties that do not exist in nature, with important applications in different food products, and pharmaceuticals. In addition, the most recent successful cases of reactions with lipases to produce modified compounds for food and nutraceuticals are reported.

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.

Encapsulated Microstructures of Beneficial Functional Lipids and Their Applications in Foods and Biomedicines

Beneficial functional lipids are essential nutrients for the growth and development of humans and animals, which nevertheless possess poor chemical stability because of heat/light-sensitivity. Various encapsulation technologies have been developed to protect these nutrients against adverse factors. Different microstructures are exhibited through different encapsulation methods, which influence the encapsulation efficiency and release behavior at the same time. This review summarizes the effects of preparation methods and process parameters on the microstructures of capsules at first. The mechanisms of the different microstructures on encapsulation efficiency and controlled release behavior of core materials are analyzed. Next, a comprehensive overview on the beneficial functional lipids capsules in the latest food and biomedicine applications are provided as well as the matching relationship between the microstructures of the capsules and applications are discussed. Finally, the remaining challenges and future possible directions that have potential interest are outlined. The purpose of this review is to convey the construction of beneficial functional lipids capsules and the function mechanism, a critical analysis on its current status and challenges, and opinions on its future development. This review is believed to promote communication among the food, pharmacy, agronomy, engineering, and nutrition industries.

Crystal network structure and stability of beeswax-based oleogels with different polyunsaturated fatty acid oils

The effect of different types of oils including camellia oil (CLO), sunflower oil (SFO), corn oil (CO) and linseed oil (LO) on the formation, crystal network structure and mechanical properties of 4%wt beeswax (BW) in oleogel was investigated. BW oleogels containing oils with higher contents of polyunsaturated fatty acids gelled first (1%wt), especially LO with higher contents of linolenic acid rather than CLO with higher contents of monounsaturated fatty acids. In comparison, oils with higher polyunsaturated fatty acid contents exhibited higher D_b with more extensive microstructure at different cooling rates, which was related to shorter nucleation induction time of crystal and higher crystallinity. Stronger van der Waals forces were observed in oleogels with higher polyunsaturated fatty acid contents especially for LO oleogel. Rheology also showed that LO oleogel with higher content of linolenic acid had higher crystallinity and lower crystal melting interfacial tension, resulting in the formation of a more stable network structure.

Structural Basis for the Regiospecificity of a Lipase from Streptomyces sp. W007

The efficiency and accuracy of the synthesis of structural lipids are closely related to the regiospecificity of lipases. Understanding the structural mechanism of their regiospecificity contributes to the regiospecific redesign of lipases for meeting the technological innovation needs. Here, we used a thermostable lipase from Streptomyces sp. W007 (MAS1), which has been recently reported to show great potential in industry, to gain an insight into the structural basis of its regiospecificity by molecular modelling and mutagenesis experiments. The results indicated that increasing the steric hindrance of the site for binding a non-reactive carbonyl group of TAGs could transform the non-specific MAS1 to a α-specific lipase, such as the mutants G40E, G40F, G40Q, G40R, G40W, G40Y, N45Y, H108W and T237Y (PSI > 80). In addition, altering the local polarity of the site as well as the conformational stability of its composing residues could also impact the regiospecificity. Our present study could not only aid the rational design of the regiospecificity of lipases, but open avenues of exploration for further industrial applications of lipases.

Synergistic effects of oleogelators in tailoring the properties of oleogels: A review

Conventional solid fats play a crucial role as an ingredient in many processed foods. However, these fats contain a high amount of saturated fats and trans fats. Legislations and dietary recommendations related to these two types of fats set forth as a consequence of evidence showing their deleterious health impact have triggered the attempts to find alternate tailor-made lipids for these solid fats. Oleogels is considered as a novel alternative, which has reduced saturated fat and no trans fat content. In addition to mimicking the distinctive characteristics of solid fats, oleogels can be developed to contain a high amount of polyunsaturated fatty acids and used to deliver bioactives. Although there has been a dramatic rise in the interest in developing oleogels for food applications over the past decade, none of them has been commercially used in foods so far due to the deficiency in their crystal network structure, particularly in monocomponent gels. Very recently, there is a surge in the interest in using of combination of gelators due to the synergistic effects that aid in overcoming the drawbacks in monocomponent gels. However, currently, there is no comprehensive insight into synergism among oleogelators reported in recent studies. Therefore, a comprehensive intuition into the findings reported on synergism is crucial to fill this gap. The objective of this review is to give a comprehensive insight into synergism among gelators based on recent literature. This paper also identifies the future research propositions towards developing oleogels capable of exactly mimicking the properties of conventional solid fats to bridge the gap between laboratory research and the food industry.

Enzymatic Synthesis of Diacylglycerol-Enriched Oil by Two-Step Vacuum-Mediated Conversion of Fatty Acid Ethyl Ester and Fatty Acid From Soy Sauce By-Product Oil as Lipid-Lowering Functional Oil

Soy sauce by-product oil (SSBO), a by-product of the soy sauce production process, is the lack of utilization due to an abundance of free fatty acid (FFA) and fatty acid ethyl ester (EE). The utilization of low-cost SSBO to produce value-added diacylglycerol (DAG)-enriched oil and its applications are promising for the sustainability of the oil industry. The objective of this study was to utilize SSBO containing a high content of EE and FFA as raw material to synthesize DAG-enriched oil and to evaluate its nutritional properties in fish. Based on different behaviors between the glycerolysis of EE and the esterification of FFA in one-pot enzymatic catalysis, a two-step vacuum-mediated conversion was developed for the maximum conversions of EE and FFA to DAG. After optimization, the maximum DAG yield (66.76%) and EE and FFA conversions (96 and 93%, respectively) were obtained under the following optimized conditions: lipase loading 3%, temperature 38°C, substrate molar ratio (glycerol/FFA and EE) 21:40, a vacuum combination of 566 mmHg within the initial 10 h and 47 mmHg from the 10th to 14th hour. Further nutritional study in fish suggested that the consumption of DAG-enriched oil was safe and served as a functional oil to lower lipid levels in serum and liver, decrease lipid accumulation and increase protein content in body and muscle tissues, and change fatty acid composition in muscle tissues. Overall, these findings were vital for the effective utilization of SSBO resources and the development of future applications for DAG-enriched oil as lipid-lowering functional oil in food.

Medium and long-chain structured triacylglycerol enhances vitamin D bioavailability in an emulsion-based delivery system: combination of in vitro and in vivo studies

Vitamin D (VitD) is an essential fat-soluble micronutrient required for maintaining and regulating calcium homeostasis. Although sunlight can provide VitD, epidemiological studies indicate that the occurrence of VitD deficiency and insufficiency is widespread. Lipids are required at all stages of VitD digestion and absorption. In this research two different medium and long-chain triacylglycerol structures, possessing identical fatty acid composition lipids, namely structured triacylglycerol (STG), and physical mixtures of medium/long-chain triacylglycerol (MCT/LCT), were selected. Our results demonstrated that STG had a significant VitD bioavailability compared to MCT/LCT. In terms of the lipid digestion and absorption, the extent of the higher free fatty acid released (69.42%, p < 0.05), extent of lipolysis (89.28%, p < 0.05), lipolysis rate (0.06 s^-1, p < 0.05), and the ratio of the long-chain fatty acid to medium-chain fatty acid of STG (4.8, p < 0.05), result in a higher capacity for accommodating VitD when forming mixed micelles (61.31%, p < 0.05). An in vivo animal study also demonstrated that STG significantly increases the delivery ability of VitD (18.75 ng mL^-1, p < 0.05). The findings of this work may have unique applications for designing novel interesterified lipids with an effective delivery capacity for fat-soluble nutrients.

Natural Gums as Oleogelators

The natural gums used as high molecular weight oleogelators are mainly polysaccharides that deliver a broad spectrum of possible utilization methods when structuring liquid fats to solid forms. The review discusses a natural gums’ structuring and gelling behavior to capture the oil droplets and form the water/oil gelling emulsions basing on their structural conformation, internal charge, and polymeric characteristics. The specific parameters and characteristics of natural gums based oleogels are also discussed. In the future, oleogels may eliminate saturated and trans fats from food products and allow the production of low-fat products, thus reducing the environmental damage caused by the excessive use of palm oil. The increasing knowledge of molecular interaction in polysaccharide chains of natural gums allows to apply more sustainable and wiser strategies towards product formulation. Innovative solutions for using oleogels based on natural polysaccharide biopolymers let incorporate them into the food matrix and replace fats completely or create blends containing the source of fats and the addition of the oleogel. The profound insight into molecular characteristics of natural gums in the function of being oleogelators is presented.

Triacylglycerol and Fatty Acid Compositions of Blackberry, Red Raspberry, Black Raspberry, Blueberry and Cranberry Seed Oils by Ultra-Performance Convergence Chromatography-Quadrupole Time-of-Flight Mass Spectrometry

The triacylglycerol (TAG) compositions of blackberry, red raspberry, black raspberry, blueberry and cranberry seed oils were examined using ultra-performance convergence chromatography-quadrupole time-of-flight mass spectrometry (UPC²-QTOF MS). A total of 52, 53, 52, 59 and 58 TAGs were detected and tentatively identified from the blackberry, red raspberry, black raspberry, blueberry and cranberry seed oils, respectively, according to their accurate molecular weight in MS1 and fragment ion profiles in MS2. OLL was the most abundant TAG in the blackberry, red raspberry and black raspberry seed oils. Furthermore, the fatty acid compositions of the five berry seed oils were directly determined by gas chromatography coupled with mass spectrometry (GC-MS). In addition, the seed oils had total phenolic contents ranging 13.68–177.06 µmol GAE (gallic acid equivalent)/L oil, and significant scavenging capacities against DPPH, peroxyl, and ABTS⁺ radicals. These results indicated that the combination of UPC² and QTOF MS could effectively identify and semi-quantify the TAGs compositions of the berry seed oils with sn-position information for the fatty acids. Understanding the TAGs compositions of these berry seed oils could improve the utilization of these potentially high nutritional value oils for human health.

Effects of partially replacing animal fat by ethylcellulose based organogels in ground cooked salami

Partial fat replacement in cooked salamis was formulated using organogels made with canola oil, ethylcellulose (EC; 6, 8, 9, 10, 11, 12 and 14%) and three types of surfactants; i.e., glycerol monostearate (GMS), stearyl alcohol/stearic acid (SOSA) and soybean lecithin (Lec). Texture profile analysis (TPA) and back extrusion tests indicated that increasing EC polymer concentration leads to harder gels regardless of the surfactant used. However, using GMS resulted in the hardest gel, whereas Lec did not strengthen the gel (mechanical stress test), but plasticized it. In general, gel hardness had a distinct effect on the binding of the organogel particle to the meat matrix, with softer gels adhering better under progressive compression. Substituting animal fat with organogel did not affect the main TPA parameters in most salami formulations, and canola oil by itself was also not significantly different from the pork and beef fat control. Using canola oil resulted in very small oil globules compared to the animal fat control, while structuring the oil yielded a microstructure with larger fat particles/globules, similar to the control. Color evaluation revealed a shift to yellow of the treatments with organogels compared to the control, but lightness and redness were not altered. The results demonstrate the potential use of structured vegetable oil to manufacture coarse ground meat products with lower saturated fat and a more favorable nutritional profile while resembling the traditional ground products.

Future trends of processed meat products concerning perceived healthiness: A review

The 21st-century consumer is highly demanding when it comes to the health benefits of food and food products. In the pursuit of attracting these consumers and easing the rise in demand for high-quality meat products, the processed meat sector is intensely focused on developing reformulated, low-fat, healthy meat products. Meat and meat products are considered the primary sources of saturated fatty acids in the human diet. Therefore, these reformulation strategies aim to improve the fatty acid profile and reduce total fat and cholesterol, which can be achieved by replacing animal fat with plant-based oils; it could be performed as direct inclusion of these oils or pre-emulsified oils. However, emulsions offer a viable option for incorporating vegetable oils while avoiding the multiple issues of direct inclusion of these oils in meat products. Processed meat products are popular worldwide and showing a gradually increasing trend of consumption. Various types of plant-based oils have been studied as fat replacers in meat products. This review will focus on possible methods to reduce the saturated fatty acid content in meat products.