Diacylglycerol Oil—Properties, Processes and Products: A Review

Selective production of functional sn-1,3-diacylglycerol by microbial lipases: A comprehensive review

Since early 1990s, diacylglycerol (DAG) has drawn a continuous trending interest among researchers and oil industries/markets as part of a reduced-energy diet due to its functions to prevent and manage obesity. With the accumulated knowledge, a stereoisomer of sn-1,3-DAG is regarded as the sole compound to contribute to DAG's functions. sn-1,3-DAG can be produced by direct esterification of free fatty acids and glycerol, partial hydrolysis of TAGs/edible oils, and glycerolysis of TAGs/edible oils with glycerol using the regioselective microbial lipases as the catalyst. However, the specific microbial lipases with high efficiency to produce sn-1,3-DAG and their catalytic mechanisms are still a mystery. Herein, we provide an overview of metabolic fates of three stereoisomers of DAGs including sn-1,3-DAG, sn-1,2-DAG and/or sn-2,3-DAG, and synthesis process for sn-1,3-DAG, and critically outline the microbial lipases to selectively produce sn-1,3-DAG, and their pathways and mechanisms, which hopefully presents a reasonable full picture of functions, synthesis schemes, and catalytic performance to improve regioselectivity and catalytic efficiency for sn-1,3-DAG production with high yield.

Effect of dry fractionation of peanut oil-based diacylglycerols on crystallization properties, oxidative stability and safety

This research employed environmentally friendly dry fractionation to systematically modify the physicochemical properties of 80 % diacylglycerol derived from peanut oil (PDAG-80), expanding its potential food applications. The properties of olein and stearin were optimized by adjusting key parameters: crystallization temperatures (11, 13, 15 and 17 °C), cooling rates (2, 5, 8 and 11 °C/h), agitation speeds (10, 20, 30 and 40 rpm)and residence times (3, 6, 9 and 12 h). Lowering the crystallization temperature and extending the residence time increased the iodine value and solid fat content of olein. Additionally, diverse fractionation parameters yieled stearin with varying crystal ratios. The resulting olein fractionated from PDAG-80, a liquid at room temperature and rich in unsaturated fatty acids, exhibited superior cloudy property and oxidative stability. These findings not only deepen the understanding of PDAG-80 physical modification, but also provide a scientific foundation for developing high value-added PDAG products within the food industry.

Biocatalytic Preparation of High-Purity DHA-Enriched Partial Glycerides through Semirational Design and Modification of Lipase Lip1897

High-purity docosahexaenoic acid (DHA) partial glycerides (PG) supplements have promising market prospects. In this study, a novel lipolytic enzyme family I lipase Lip1897, derived from Streptomyces thermodiastaticus, was identified and modified to be applied to the enzymatic synthesis of high-purity docosahexaenoic acid partial glycerides (DHA-PG). Lip1897 displayed optimal activity and good stability at 55 °C and pH 5.0. Further study found that Lip1897 could catalyze the hydrolysis of DHA triglycerides (TG) and DHA ethyl esters (EE), the esterification of DHA, and the glycerolysis of docosahexaenoic acid ethyl esters (DHA-EE), which had good prospects for industrial application. To enhance the catalytic selectivity of Lip1897, semirational design and modification based on structural analysis were carried out, and the mutant Lip1897-H106W showed a 1.86-fold increase in glycerolysis activity. The molecular docking results indicated that the mutant bound to the substrate DHA-EE at lower energy and with a more stable conformation. Under the solvent-free system, Lip1897-H106W was employed to catalyze the glycerolysis of DHA-EE for the synthesis of DHA-PG, achieving a promising DHA-EE conversion rate of 95.02% and a high DHA-PG yield of 70.85%. The efficient glycerolysis for preparing high-purity DHA-PG was realized. This research provides a reference for enhancing the efficiency of specific configurational functional lipid biosynthesis through enzyme discovery and modification.

Elucidation of crystallization mechanism of high-purity diacylglycerol from nano-crystal to three dimensional-network by controlling cooling rate

The microstructure of lipids significantly affects the three-dimensional network, ultimately determining their physical properties. Due to the unique physical properties of diacylglycerol (DAG), it can be effectively used as a functional substitute for traditional oil in plastic fats. This study explored the microstructure and physicochemical properties of high-purity sn-1,3 lauryl diacylglycerol (LDAG), palmityl diacylglycerol (PDAG), and their acyl migration equilibrium products (ME-DAG, sn-1,3 DAG: sn-1,2 DAG = 65:35) under different cooling rates. As the cooling rate increased, the hydrogen bond force and order degree of DAGs also rose. Sn-1,3 LDAG exhibited a larger lattice space, thicker nanoplatelet structure, and larger crystals than sn-1,3 PDAG at the micro-scale. The increasing cooling rate resulted in the transformation of β1 into unstable β2 forms in sn-1,3 DAGs. ME-PDAG demonstrated better resistance to β crystal growth at higher cooling rates, while ME-LDAG's crystal form remained unaffected by changes in cooling rate. ME-LDAG exhibited superior resistance to cooling rate compared to ME-PDAG. ME-DAG formed Maltese cross crystals after rapid cooling, potentially contributing to its hardness.

Novel diacylglycerol oil-based nanostructured lipid carriers improves the stability and digestibility of lycopene

Diacylglycerol (DAG) has garnered attention for its safe and nutritious qualities, and its utilization in emulsion systems to encapsulate hydrophobic bioactives is anticipated to enhance their bioaccessibility. Thus, this study aimed to evaluate the influence of DAG oil as a carrier on the stability and digestive characteristics of nanostructured lipid carriers (NLCs) containing lycopene (LYC). The results indicated that DAG oil demonstrated superior storage and heating stability in comparison to triacylglycerol (TAG) oil. Furthermore, NLCs formulated with DAG oil exhibited a faster rate of lipolysis (>76.3%) and higher loading capacity (1.48%), resulting in an approximate 11% enhancement in the bioaccessibility of LYC (reaching up to 31.4%). DAG oils show considerable potential for enhancing and prolonging the properties and bioactivity of NLC carriers, thereby boosting bioaccessibility. The incorporation of DAG oil in food systems holds promise for enriching their functionality over traditional TAG oil.

Immobilization of Lipase from Thermomyces Lanuginosus and Its Glycerolysis Ability in Diacylglycerol Preparation

In the glycerolysis process for diacylglycerol (DAG) preparation, free lipases suffer from poor stability and the inability to be reused. To address this, a cost-effective immobilized lipase preparation was developed by cross-linking macroporous resin with poly (ethylene glycol) diglycidyl ether (PEGDGE) followed by lipase adsorption. The selected immobilization conditions were identified as pH 7.0, 35 °C, cross-linking agent concentration 2.0%, cross-linking time 4 h, lipase amount 5 mg/g of support, and adsorption time 4 h. Enzymatic properties of the immobilized lipase were analyzed, revealing enhanced pH stability, thermal stability, storage stability, and operational stability post-immobilization. The conditions for immobilized enzyme-catalyzed glycerolysis to produce DAG were selected, demonstrating the broad applicability of the immobilized lipase. The immobilized lipase catalyzed glycerolysis reactions using various oils as substrates, with DAG content in the products ranging between 35 and 45%, demonstrating broad applicability. Additionally, the changes during the repeated use of the immobilized lipase were characterized, showing that mechanical damage, lipase leakage, and alterations in the secondary structure of the lipase protein contributed to the decline in catalytic activity over time. These findings provide valuable insights for the industrial application of lipase.

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.

Temperature dependence of acoustic parameters in pure and blended edible oils: Implications for characterization and authentication

This research investigates the temperature-dependent variation of diverse acoustic parameters in samples of edible oils. It further supplements previous studies on the effectiveness of non-destructive ultrasonic inspection in the authentication of edible oils. The oils under examination consist of pure samples of olive, sunflower, and corn oils, as well as variable mixtures ranging from 20 % to 80 % of the more expensive one (olive oil) with the other two, simulating a hypothetical adulteration scenario. The studied acoustic parameters are related to the velocity, attenuation, and frequency components present in 2.25 MHz ultrasonic waves propagating through the oil samples within a temperature range of 24 °C to 34 °C. The results confirm the suitability of non-destructive ultrasonic inspection in evaluating and detecting the adulteration of olive oil with economically inferior oils such as sunflower and corn. Additionally, this study provides added value by laying the groundwork for a non-destructive and innovative determination of the fatty acid profile of an edible oil based on the evolution of the aforementioned ultrasonic parameters with temperature. The findings hold potential for enhancing the authenticity assessment and quality control of edible oils in the food industry.

Exploring Diacylglycerol Oil-Based Oleogels as Effective Stabilizers in Peanut Butter: Performance, Structural Insights, and Sensory Evaluation

In the pursuit of reducing oil separation in peanut butter, oleogels synthesized from diacylglycerol (DAG)-rich peanut oils, using glycerol monostearate (GMS) as the gelator, were examined as alternative stabilizers. In comparison to triacylglycerol (TAG)-rich peanut oils, the DAG oil-based oleogels exhibited better oil-binding capacities across increasing GMS concentrations. Intriguingly, thermal and rheological assessments pointed to a weaker network structure in DAG oil oleogels, as evidenced by their lower crystallization temperatures and reduced viscoelastic parameters (G' and G''). Insight from infrared spectroscopy revealed that this could stem from heightened intermolecular hydrogen bonding between the DAG oil and the gelator. When applied to peanut butter, DAG oil oleogels demonstrated efficacy in minimizing oil separation. Extended storage trials affirmed the long-term stability of peanut butter formulations incorporating these oleogels. Furthermore, sensory evaluations by panelists underscored favorable impressions, suggesting potential consumer acceptance. Overall, this study illuminates the promising role of DAG oleogels as effective, alternative stabilizers in peanut butter formulations.

Glyceryl Diesters

The Expert Panel for Cosmetic Ingredient Safety reviewed newly available studies since their original assessment in 2002, along with updated information regarding product types and concentrations of use, and confirmed that these 17 glyceryl diesters are safe as cosmetic ingredients in the practices of use and concentration as described in this report.

Enzymatic glycerolysis for the conversion of plant oils into animal fat mimetics

Substituting animal-based fats with plant-based fats of similar stability and functionality has always posed a significant challenge for the food industry. Enzymatic glycerolysis products are systems formed by converting native triacylglycerols in liquid oils into monoacylglycerols and diacylglycerols, mainly studied in the last few years for their unique structural ability. This study aims to modify and scale up the glycerolysis process of different plant oils, e.g., shea olein, palm olein, tigernut, peanut, cottonseed, and rice bran oils, with the goal of producing animal fat mimetics. The reactions were conducted at 65 °C, with a plant oil:glycerol molar ratio of 1:1, and without the addition of water, using a lab-scale reactor to convert up to 2 kg of oil into solid fat. Product characteristics were comparable at both laboratory and pilot plant scales, supporting the commercial viability of the process. Oil systems containing higher levels of both saturated and monounsaturated fatty acids, such as shea olein and palm olein, displayed higher solid fat content at elevated temperatures and broader melting profiles with significantly higher melting points. Comparison of the thermal softening behavior and mechanical properties of these systems with those of pork, beef, and lamb fat showed their high potential to replace adipose fat in the new generation of plant-based meat analogs.

Konjac glucomannan promoted fabrication of diacylglycerol oil-based oleogels through emulsion-templated approach: Comparison with triacylglycerol oleogels

Konjac glucomannan (KGM) combined with hydroxypropyl methyl cellulose was used to fabricate diacylglycerol oleogels (DGOs) through the emulsion-templated method, and compared with triacylglycerol oleogels (TGOs). The appearance and microstructure results showed that stable emulsions and oleogels could be formed in the presence of 0.2-0.6 wt% KGM. Higher KGM concentrations resulted in a stronger gel structure in oleogels, whose thixotropic recovery percentages were 50.45-75.20 %. From LF-NMR determination, the higher concentration of KGM presented earlier transverse relaxation (T2) time, and the T2 parameters of DGOs were higher than that of TGOs. Texture and oil loss analysis indicated that the mechanical strength and oil holding ability of DGOs were slightly lower than those of TGOs. This study demonstrated the advantages of biopolymers as thickening agents for obtaining stable emulsion and oleogels. The specific characteristics of DGOs distinguished from TGOs should be attributed to their different properties (unsaturation, viscosity, polarity, etc.) between the liquid oils.

Exploring the fates and molecular changes of different diacylglycerol-rich lipids during in vitro digestion

This study aimed to support the pursuit of healthy oils and investigate the relationships between lipid compositions and digestion fates of diacylglycerol (DAG)-rich lipids using an in vitro digestion model. Soybean-, olive-, rapeseed-, camellia-, and linseed-based DAG-rich lipids (termed SD, OD, RD, CD, and LD, respectively) were selected. These lipids exhibited identical lipolysis degrees (92.20-94.36 %) and digestion rates (0.0403-0.0466 s^-1). The lipid structure (DAG or triacylglycerol) was a more important factor affecting the lipolysis degree than other indices (glycerolipid composition and fatty acid composition). For RD, CD and LD with similar fatty acid compositions, the same fatty acid had different release levels, probably due to their different glycerolipid compositions (causing different distributions of the fatty acid in UU-DAG, USa-DAG and SaSa-DAG; U: unsaturated fatty acids, Sa: saturated fatty acids). This study provides insights into the digestion behaviors of different DAG-rich lipids and supports their food or pharmaceutical applications.

Constitution and reconstitution of microcapsules with high diacylglycerol oil loading capacity based on whey protein isolate / octenyl succinic anhydride starch/ inulin matrix

The aim of this study was to constitute microcapsule systems with high oil loading capacity by octenyl succinic anhydride (OSA) starch, whey protein isolate (WPI) and inulin (IN) substrates to provide a new method for encapsulating diacylglycerol oil. Specifically, this study characterizes the physicochemical properties and reconstitution capacity of highly oil loading diacylglycerol microcapsules by comparing the wall encapsulation capacity of the binary wall system OSA-IN, WPI-IN and the ternary wall system WPI-OSA (1:9, 5:5, 9:1)-IN for diacylglycerol oil. It was found that WPI-OSA (5:5)-IN significantly improved the water solubility of microcapsules (86.11 %) compared to OSA-IN microcapsules, and the addition of WPI made the surface of microcapsules smoother and increased the thermal stability and solubility of microcapsules; the addition of OSA enhanced the wettability of microcapsules compared to WPI-IN. In addition, WPI-OSA (5:5)-IN microcapsules have the highest encapsulation efficiency (96.03 %), high emulsion stability after reconstitution, and the smallest droplet size (212.83 nm) after 28 d. Therefore, the WPI-OSA-IN composite system is suitable for the production of highly oil-loaded microencapsulated systems with excellent reconstitution ability to expand the application of diacylglycerol oil.

Engineering the Thermostability of the Mono- and Diacylglycerol Lipase SMG1 for the Synthesis of Diacylglycerols

Diacylglycerols (DAGs) display huge application prospectives in food industries. Therefore, new strategies to produce diacylglycerides are needed. Malassezia globose lipase (SMG1) could be used to synthesize DAGs. However, the poor thermostability of SMG1 seriously hampers its application. Herein, a rational design was used to generate a more thermostable SMG1. Compared with the wild type (WT), the M5D mutant (Q34P/A37P/M176V/G177A/M294R/ G28C-P206C), which contains five single-point mutations and one additional disulfide bond, displayed a 14.0 °C increase in the melting temperature (T_m), 5 °C in the optimal temperature, and 1154.3-fold in the half-life (t_1/2) at 55 °C. Meanwhile, the specific activity towards DAGs of the M5D variant was improved by 3.0-fold compared to the WT. Molecular dynamics (MD) simulations revealed that the M5D mutant showed an improved rigid structure. Additionally, the WT and the M5D variants were immobilized and used for the production of DAGs. Compared with the WT, the immobilized M5D-catalyzed esterification showed a 9.1% higher DAG content and a 22.9% increase in residual activity after nine consecutive cycles. This study will pave the way for the industrial application of SMG1.

Water-in-oil emulsions enriched with alpha-linolenic acid in diacylglycerol form: Stability, formation mechanism and in vitro digestion analysis

This study developed an alpha-linolenic acid (ALA) supplement with emulsion form using ALA-rich diacylglycerol (ALA-DAG) and ALA-DAG stearin (DAG-SF) as a new source of ALA and emulsifier. Stable, commercial surfactant-free W/O emulsions with 90 wt% oil phase (including DAG-SF and ALA-DAG with 10:90 - 20:80 wt ratio) was fabricated. Microstructure and Raman spectra revealed that the compact crystal networks and high amounts of solid acyl chains were responsible for high emulsion stability. These emulsions exhibited good potential in improving the ALA nutritional status (with ALA release level of 60.49% - 62.98%). Furthermore, the emulsifier-to-oil ratio greatly impacted the emulsion texture (solid-like or liquid-like) and emulsions showed great oxidation stability (2.80 - 3.09 meq/kg lipid of peroxide value at 6th week). The tunable texture and high oxidation stability make this emulsion system useful for a wide range of food products. This developed emulsion system could provide valuable information for other important fatty acids supplement.

Characteristics and feasibility of olive oil-based diacylglycerol plastic fat for use in compound chocolate

With an aim to prepare the healthier functional chocolate, olive oil-based diacylglycerol plastic fat (ODAGP) was prepared by mixing olive oil-based diacylglycerol stearin (O-DAGS) and olive oil-based diacylglycerol olein (O-DAGO) as confectionery fat in compound chocolate. We reported the physicochemical properties of ODAGP and ODAGP-CB blends, and then evaluated their application potential in compound chocolate based on sensory, blooming property and polymorphic transition. ODAGP (40% O-DAGS) showed a wide plastic range (7.1-45.2%) and high component compatibility. The crystal properties results indicated that ODAGP mainly existed in stable β-forms (β₁ and β₂). On the other hand, the ODAGP-CB binary system containing 10-40% ODAGP displayed similar melt-in-mouth property and crystal polymorphism (Form V) to natural CB. Compound chocolate prepared with ODAGP-CB blends obtained satisfactory overall acceptability (score > 7.8) and showed stronger fat bloom resistance.

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.

Study of rapeseed oil gelation induced by commercial monoglycerides using a chemometric approach

Commercial oleogelators rich in monoglycerides (MGs) are complex mixtures of acylglycerides with variable gelling properties, depending on the oil used and their concentration. In this study we developed a chemometric approach to identify the key parameters involved in gelling process. Analytical parameters have been defined, using GC and NMR analysis to identify fatty acids and acylglycerides composing the mixtures. Specific acylglyceride families and compound ratios were calculated to streamline the analytical results. To determine the key analytical parameters, artificial neural networks were used in a QSPR study related to the gelling properties measured by rheology through oscillatory experiments. At low oleogelator concentrations, the MGs especially rich in C16:0 and the ratio of specific isomers both have a positive influence on G'. For high oleogelator concentrations, C18:0-rich acylglycerides and unsaturated/saturated fatty acid ratios have a positive influence on G'. Conversely, at low concentrations, C18:0-rich acylglycerides show a lesser effect on G'.

Effect of nisin and potassium sorbate additions on lipids and nutritional quality of Tan sheep meat

Nisin and potassium sorbate as preservatives are used in a broad range of meat. A lipidomic evaluation was performed on Tan sheep meat treated by two types of preservatives. The addition of potassium sorbate resulted in higher lipid losses compared with nisin treatment. Furthermore, 106 significant lipids of 12 lipid classes (PC, PS, LPS, LPC, PE, PI, LPE, TG, Cer, DG, SM, Sph) with variable importance in projection scores greater than 1.0 were detected and qualified to distinguish different preservatives added meat using UHPLC-Q-Orbitrap MS/MS. LOD and LOQ were 0.12-0.32 μg kg^-1 and 0.35-0.89 μg kg^-1, indicating high sensitivity and excellent analytical characteristics in the study. Nisin was confirmed to be the better preservative for prolonging the shelf life of Tan sheep meat while reducing the loss of nutrients. These results could provide a strong cornerstone for future research on preservatives in meat products.

Sequence and structure-based method to predict diacylglycerol lipases in protein sequence

Lipase enzymes play a central role in biotechnology and the food industry. Diacylglyceride lipases (DAG) have received considerable attention due to their physiological significance and potential industrial usage. However, compared to the wide application of triacylglycerol (TAG) lipases, DAG lipases have a limited application due to their low thermostability and specific activity. The molecular basis of substrate specificity of DAG lipases remains elusive, making structure-guided engineering of TAG to DAG lipase difficult. Besides, the number of available DAG lipases is limited compared to TAG lipases. In the current study, we identified structural consensus motifs of DAG lipases that contribute to their DAG specificity on a structural comparison of DAG and TAG lipases. To find potential DAG lipases, sequence motifs and predicted secondary structures were used to screen millions of protein sequences and predict new DAG lipases. In total, 83 new putative DAG lipases were identified. The predicted DAG lipases were validated by expression of randomly chosen putative DAG lipases followed by functional assay for their DAG and TAG specific activity. The reported method is efficient and cost-effective for discovering new DAG lipases used in the food industry after the required characterization to meet potential application needs.

Fabrication and characterization of stable oleofoam based on medium-long chain diacylglycerol and β-sitosterol

Oleofoams have emerged as attractive low-calorie aeration systems, but saturated lipids or large amount of surfactants are commonly required. Herein, an innovative strategy was proposed to create oleofoams using medium-long chain diacylglycerol (MLCD) and β-sitosterol (St). The oleofoams prepared using MLCD and St in ratios of 15:5 and 12:8 exhibited smaller bubble size and much higher stability. MLCD crystals formed rigid Pickering shell, whereby air bubbles acted as "active fillers" leading to enhanced rigidity. Both Pickering and network stabilization for the MLCD-St oleofoam provided a steric hindrance against coalescence. The gelators interacted via hydrogen bonding, causing a condensing effect in improving the gel elasticity. The oleofoams and foam-based emulsions exhibited a favorable capacity in controlling volatile release where the maximum headspace concentrations and partition coefficients showed a significantly decrease. Overall, the oleofoams have shown great potential for development of low-calorie foods and delivery systems with enhanced textural and nutritional features.

Rhizopus oryzae Lipase, a Promising Industrial Enzyme: Biochemical Characteristics, Production and Biocatalytic Applications

Lipases are biocatalysts with a significant potential to enable a shift from current pollutant manufacturing processes to environmentally sustainable approaches. The main reason of this prospect is their catalytic versatility as they carry out several industrially relevant reactions as hydrolysis of fats in water/lipid interface and synthesis reactions in solvent-free or non-aqueous media such as transesterification, interesterification and esterification. Because of the outstanding traits of Rhizopus oryzae lipase (ROL), 1,3-specificity, high enantioselectivity and stability in organic media, its application in energy, food and pharmaceutical industrial sector has been widely studied. Significant advances have been made in the biochemical characterisation of ROL particularly in how its activity and stability are affected by the presence of its prosequence. In addition, native and heterologous production of ROL, the latter in cell factories like Escherichia coli, Saccharomyces cerevisiae and Komagataella phaffii (Pichia pastoris), have been thoroughly described. Therefore, in this review, we summarise the current knowledge about R. oryzae lipase (i) biochemical characteristics, (ii) production strategies and (iii) potential industrial applications.

Enzymatic glycerolysis converts vegetable oils into structural fats with the potential to replace palm oil in food products

Current trans fat replacement strategies provide food products with acceptable textural and sensory properties on a large scale, and at a reasonable price, but carry health and environmental burdens. Palm oil is used extensively because of its high solidity and functionality; however, increased production has led to deforestation throughout the world's tropical regions. To reduce dependence on palm oil it is necessary to find a means of structuring a variety of readily available vegetable oils. Using cottonseed and peanut oils, among others, we show that enzymatic glycerolysis can structure liquid oils into solid fats through monoacylglycerol and diacylglycerol production from their native triacylglycerols without the addition of saturated or hydrogenated fat, thus not altering fatty acid composition. Solid fat contents of cottonseed and peanut oils were increased from 8% to 29% and 9% to 30% at 5 °C, respectively, and 21% and 10% at 20 °C, respectively. Additionally, oil-binding capacity was enhanced significantly. These novel oils were used to produce margarine and peanut butter with similar textural properties to commercial products and, importantly, represent a healthy and sustainable means to replace hydrogenated or saturated fats.

Effect of Purification Methods on the Physicochemical and Thermodynamic Properties and Crystallization Kinetics of Medium-Chain, Medium-Long-Chain, and Long-Chain Diacylglycerols

Medium-chain diacylglycerol (MCD), medium-long-chain diacylglycerol (MLCD), and long-chain diacylglycerol (LCD) were prepared through enzymatic esterification using different conditions at temperatures of 55-70 °C and reaction times of 1.5-5 h and in the presence of 5-6% Novozym 435. Subsequently, purification was performed using three different techniques, namely, molecular distillation (MD), deodorization (DO), and silica gel column chromatography (SGCC). Variations in terms of the physicochemical and thermodynamic properties, crystallization properties, and kinetics of the diacylglycerols (DAGs) before and after purification were determined. Irrespective of the DAG chain lengths, SGCC was able to produce samples with high DAG purity (96-99 wt %), followed by MD (58-79 wt %) and DO (39-59 wt %). A higher 1,3-DAG/1,2-DAG ratio was recorded for all samples, with the highest ratio recorded for SGCC purified samples. Regardless of the purification techniques used, the solid fat content (SFC) profiles of crude samples with steep curves were altered post-purification, showing a gradual increment in SFC along with increasing temperature. Modification of the Avrami constant and coefficient suggested the modification of the crystal growth mechanism post-purification. Crystallization and melting temperatures of products with a higher DAG purity were shifted to a higher temperature region. Variations were also reflected in terms of the crystal polymorphism, whereby the α and β' crystals transitioned into the more stable β form in purified samples accompanied by modification in the microstructures and crystal sizes. However, there was insignificant change in the morphology of MLCD crystal after purification, except for the decrease in crystal sizes. In conclusion, synthesis of MCD, MLCD, and LCD comprising different DAG purities had distinctive SFC profiles, thermodynamic properties, crystallization kinetics, and crystal morphologies, which can be further incorporated into the preparation of a variety of fat products to obtain end products with desired characteristics.

Effects of diacylglycerol and triacylglycerol from peanut oil and coconut oil on lipid metabolism in mice

Different chain lengths diacylglycerols (DAG) (long- and medium-chain) were synthesized from peanut and coconut oils. The effects of DAG with different chain lengths on body fat, blood lipids, and lipid metabolism-related enzymes in the liver and adipose tissue of C57BL/6J mice were investigated. Compared to peanut and coconut oils containing triacylglycerol (TAG), DAG-rich oils can significantly reduce the body weight, kidney weight, serum triglyceride (TG) content, hepatic fatty acid synthase (FAS), and Acetyl-CoA carboxylase (ACC) enzyme levels (p < 0.05) in C57BL/6J mice. Therefore, the effect of coconut oil DAG on improving body fat metabolism was probably due to the impact of DAG. Meanwhile, the body weight and serum TG content in coconut oil DAG group were lower than those in peanut oil DAG group. In addition, the spleen weight, hepatic ACC, and lipoprotein lipase (LPL) enzymes in coconut oil DAG group (0.07 ± 0.01 g, 2.08 ± 0.42 ng/mg pro, and 18.44 ± 5.23 ng/mg pro, respectively) were significantly lower than those in peanut oil DAG group. Although coconut oil DAG and peanut oil DAG have different fatty acid compositions, their effects on lipid metabolism showed no significant changes. Coconut oil DAG (peanut oil DAG) showed the improved lipid metabolism than that of coconut oil (peanut oil), which was probably due to the effect of DAG. PRACTICAL APPLICATION: Peanut and coconut oils are common edible oils. The oil containing DAG synthesized decreased the body weight and lipid accumulation in mice. Coconut oil is rich in medium-chain fatty acids, while peanut oil mainly consists of long-chain fatty acids. Due to the different contents of fatty acids, the synthesized structural lipids have different effects on lipid metabolism. Medium-chain triglycerides were considered as agents to alleviate obesity.

Production of diacylglycerols through glycerolysis with SBA-15 supported Thermomyces lanuginosus lipase as catalyst

BACKGROUND

In this study, SBA-15 was functionalized by silane coupling reagents, then lipase from Thermomyces lanuginosus (TLL) was immobilized onto the parent and the organically modified SBA-15 for diacylglycerol (DAG) production through glycerolysis.

RESULTS

Diacylglycerol content of 54.77 ± 0.63%, and triacylglycerol (TAG) conversion of 77.75 ± 1.24%, were obtained from the parent SBA-15 supported TLL-mediated glycerolysis reaction in a solvent-free system. However, poor performance was unexpectedly observed when co-solvents were introduced into the reaction system. After organic modification, the functionalized SBA-15 supported TLL samples all exhibited reasonable performance, producing DAG content over 40 wt% and TAG conversion over 70 wt%. Higher DAG content, up to 59.19 ± 1.10%, was observed from the phenyl group-modified SBA-15 supported TLL. The operational stability of the immobilized TLL samples in glycerolysis was also improved after organic functionalization. The phenyl group-modified SBA-15 supported TLL showed good reusability in the present glycerolysis reaction, and 95.21 ± 4.87% of the initial glycerolysis activity remained after five cycles of reuse.

CONCLUSION

The organic modification of SBA-15 improved the catalytic performance of its supported TLL in glycerolysis, in terms of TAG conversion, DAG content, and reusability. © 2019 Society of Chemical Industry.

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

Structured lipids (SLs) refer to a new type of functional lipids obtained by chemically, enzymatically, or genetically modifying the composition and/or distribution of fatty acids in the glycerol backbone. Due to the unique physicochemical characteristics and health benefits of SLs (for example, calorie reduction, immune function improvement, and reduction in serum triacylglycerols), there is increasing interest in the research and application of novel SLs in the food industry. The chemical structures and molecular architectures of SLs define mainly their physicochemical properties and nutritional values, which are also affected by the processing conditions. In this regard, this holistic review provides coverage of the latest developments and applications of SLs in terms of synthesis strategies, physicochemical properties, health aspects, and potential food applications. Enzymatic synthesis of SLs particularly with immobilized lipases is presented with a short introduction to the genetic engineering approach. Some physical features such as solid fat content, crystallization and melting behavior, rheology and interfacial properties, as well as oxidative stability are discussed as influenced by chemical structures and processing conditions. Health-related considerations of SLs including their metabolic characteristics, biopolymer-based lipid digestion modulation, and oleogelation of liquid oils are also explored. Finally, potential food applications of SLs are shortly introduced. Major challenges and future trends in the industrial production of SLs, physicochemical properties, and digestion behavior of SLs in complex food systems, as well as further exploration of SL-based oleogels and their food application are also discussed.

Emulsification and oxidation stabilities of DAG-rich algae oil-in-water emulsions prepared with the selected emulsifiers

BACKGROUND

Diacylglycerol (DAG) reduces body weight, suppresses body fat accumulation, and lowers the blood lipid concentration, and docosahexaenoic acid (DHA) can reduce the risk of occurrence of coronary artery diseases.

RESULTS

DAG-rich algae oil with a high DHA content (55.9%) was synthesized via the lipase-catalyzed glycerolysis of algae oil, which consisted of triacylglycerol (43.9 mol%), DAG (40.9 mol%), and monoacylglycerol (15.2 mol%). The DAG-rich algae oil-in-water emulsions were prepared using three emulsifiers [whey protein concentrate (WPC), Tween80, and Tween80 + Span80]. The WPC-emulsion formed a thicker serum layer (6.67% at day 51) and larger oil droplets (d₃₂ , 0.37 μm at day 28) than the Tween80- and Tween80 + Span80-emulsions (3.33-4.17%; 0.26 μm), and an upper cream layer with excess oil droplets was observed in only the WPC-emulsion, indicating that WPC-emulsion possesses the lowest emulsification stability. The hydroperoxide value and reduction rate of the DHA content were higher in the WPC-emulsions than in the Tween80- and Tween80 + Span80-emulsions during storage, which suggested that the WPC-emulsion had the lowest oxidation stability.

CONCLUSION

The DAG-rich algae oil-in-water emulsion prepared with suitable emulsifiers, such as non-ionic emulsifiers, would have excellent emulsification and oxidative stabilities and provides a health benefit for special purposes in the food processing industry. © 2019 Society of Chemical Industry.

Controlling lipid intestinal digestibility using various oil structuring mechanisms

This research demonstrates the ability to direct the rate and extent of lipid hydrolysis of oleogels using a combination of different structuring agents.

Enzymatic glycerolysis-interesterification of palm stearin-olein blend for synthesis structured lipid containing high mono- and diacylglycerol

The objective of this research was to evaluate enzymatic glycerolysis-interesterification to synthesize structured lipids (SLs) containing high monoacylglycerol (MAG) and diacylglycerol (DAG) from a palm stearin-olein blend (PS-PO blend). The results showed that the optimum conditions for the solvent to fat ratio, glycerol to fat ratio, and enzyme concentration were 2:1 (v/w), 1.5:1, and 15% (w/w), respectively. The conversion rate of MAG and DAG decreased at a high glycerol to fat ratio, low solvent to fat ratio, and high enzyme concentration due to an increase in viscosity and low agitation effectiveness. The emulsion capacity and stability of the SLs were 60.19% and 96.80%, respectively. The hardness of the SLs increased about 3.1-fold. The MAG, DAG, and triacylglycerol conversion rates were 0.45, 0.48, and 1.02%/h, respectively. Thus, glycerolysis-interesterification of a PS-PO blend increased DAG and MAG concentrations and further improved the hardness, emulsion capacity, and emulsion stability of the SLs.

1-Laurin-3-Palmitin as a Novel Matrix of Solid Lipid Particles: Higher Loading Capacity of Thymol and Better Stability of Dispersions Than Those of Glyceryl Monostearate and Glyceryl Tripalmitate

To develop solid lipid nanoparticles (SLNs) with a new lipid matrix for delivery of hydrophobic bioactive molecules, high purity 1-laurin-3-palmitin (1,3-LP) was synthesized and the prepared 1,3-LP SLNs were compared with those of two common SLN matrices in glyceryl monostearate (GMS) and glyceryl tripalmitate (PPP). Conditions of preparing SLNs were first optimized by evaluating the particle size, polydispersity index (PDI), zeta-potential, and stability. Thereafter, the performance of SLN loading of a model compound in thymol was studied. The loading capacity of thymol in 1,3-LP SLNs was 16% of lipids and higher than 4% and 12% for GMS- and PPP-SLNs, respectively. The 1,3-LP SLNs also had the best efficiency to entrapment thymol during the prolonged storage. X-ray diffraction (XRD) analyses confirmed the excellent crystalline stability of 1,3-LP leading to the stable entrapment efficiency and better stability of thymol-loaded SLNs. Conversely, the polymorphic transformation of GMS and PPP resulted in the declined entrapment efficiency of thymol in the corresponding SLNs. This work indicated the 1,3-diacylglycerol (DAG) SLNs could be used as a promising delivery system for the encapsulation of hydrophobic bioactive molecules with high loading capacity and stability.

Fatty Acid Profile, Phytochemicals, and Other Substances in Canarium odontophyllum Fat Extracted Using Supercritical Carbon Dioxide

This study aims to identify potential phenolic compounds, terpenoids, and other phytochemicals, as well as fatty acid profile and peptides in Canarium odontophyllum (CO) oil and oleoresin, extracted using supercritical carbon dioxide. LC-ESI-MS was applied in separation and tentative identification of phytochemicals in CO oil and oleoresin. Based on the results, 11 common fatty acids and their isomers, monoglycerides, diglycerides, as well as other types of lipid, were tentatively identified in the CO oil and oleoresin. The identified fatty acids consisted of saturated fatty acids (C8-C16), monounsaturated fatty acids (C16:1 and C18:1), polyunsaturated fatty acids (C18:2, C18:3, C18:4, and C20:3), and other unclassified fatty acids. The tentatively identified phenolic compounds were phenolic acids, flavonoids, lignans, and a phenolic monoester. Triterpenes, sesquiterpenes, and apocarotenoids were the terpenoids found in CO oil and oleoresin. Besides these typical bioactives, some volatiles, aromatic compounds, peptides, and other known and unknown phytochemicals were also tentatively identified in the oil and oleoresin of CO. Some of these compounds are new compounds identified in CO oil and oleoresin, which are not found in many other fruit oils. Although CO oil and oleoresin contain a small number of phytochemicals, their contribution as antioxidants may prevent several diseases. In this study, we hypothesized that CO oleoresin contains certain types of fatty acids that render its semi-solid together with other chemical components which are not found in CO oil. This is the first study that tentatively identified fatty acids, peptides, and potential phytochemicals in CO oil and oleoresin using LC-ESI-MS.