Fast synthesis of 1,3-DAG by Lecitase® Ultra-catalyzed esterification in solvent-free system

Preparation of vacuum-assisted conjugated linoleic acid phospholipids under nitrogen: Mechanism of acyl migration of lysophospholipids

Sn-Glycerol-3-phosphatidylcholine (GPC) was prepared by hydrolysis of phosphatidylcholine (PC) catalyzed by phospholipase A1 (PLA1). Nitrogen flow assisted the esterification of conjugated linoleic acid (CLA) and GPC to produce conjugated linoleic acid lysophosphatidylcholine (LPC - CLA). The effects of different reaction conditions on the PC conversion and acyl migration rates were investigated, and the acyl migration mechanism under acidic and alkaline conditions was studied. In addition, the optimum conditions for the esterification of CLA and GPC were selected. The optimal condition for the hydrolysis of PC was an enzyme loading of 5 %, pH of 5, reaction temperature of 50 ℃, and reaction time of 3 h. The results also showed that the maximum esterification rate reached 82.37 % at an enzyme loading of 15 %, CLA/GPC molar ratio of 50:1, and vacuum pressure of 13.3 kPa. This study not only improved the bioavailability of PC but also effectively increased the content of LPC - CLA.

Preparation and characterization of diacylglycerol via ultrasound-assisted enzyme-catalyzed transesterification of lard with glycerol monolaurate

The study aimed to evaluate the effect of ultrasonic pretreatment on the transesterification of lard with glycerol monolaurate (GML) using Lipozyme TL IM to synthesize diacylglycerol (DAG), and the physicochemical properties of lard, GML, ultrasonic-treated diacylglycerol (named U-DAG), purified ultrasonic-treated diacylglycerol obtained by molecular distillation (named P-U-DAG), and without ultrasonic-treated diacylglycerol (named N-U-DAG) were analyzed. The optimized ultrasonic pretreatment conditions were: lard to GML mole ratio 3:1, enzyme dosage 6 %, ultrasonic temperature 80 °C, time 9 min, power 315 W. After ultrasonic pretreatment, the mixtures reacted for 4 h in a water bath at 60 °C, the content of DAG reached 40.59 %. No significant variations were observed between U-DAG and N-U-DAG in fatty acids compositions and iodine value, while P-U-DAG had lower unsaturated fatty acids than U-DAG. Differential scanning calorimetry analysis showed that the melting and crystallization properties of DAGs prepared by ultrasonic pretreatment significantly differed from lard. FTIR spectra noted transesterification reaction from lard and GML with and without ultrasonic pretreatment would not change the structure of lard. However, thermogravimetric analysis proved that N-U-DAG, U-DAG, and P-U-DAG had lower oxidation stability than lard. The higher the content of DAG, the faster the oxidation speed.

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.

Enantioselective Transesterification of Allyl Alcohols with (E)-4-Arylbut-3-en-2-ol Motif by Immobilized Lecitase™ Ultra

Lecitase™ Ultra was immobilized on four different supports and tested for the first time as the biocatalyst in the kinetic resolution of racemic allyl alcohols with the (E)-4-arylbut-3-en-2-ol system in the process of transesterification. The most effective biocatalyst turned out to be the enzyme immobilized on agarose activated with cyanogen bromide (LU-CNBr). The best results (E > 200, ees and eep = 95–99%) were obtained for (E)-4-phenylbut-3-en-2-ol and its analog with a 2,5-dimethylphenyl ring whereas the lowest ee of kinetic resolution products (90%) was achieved for the substrate with a 4-methoxyphenyl substituent. For all substrates, (R)-enantiomers were esterified faster than their (S)-antipodes. The results showed that LU-CNBr is a versatile biocatalyst, showing high activity and enantioselectivity in a wide range of organic solvents in the presence of commonly used acyl donors. High operational stability of LU-CNBr allows it to be reused in three subsequent reaction cycles without negative effects on the efficiency and enantioselectivity of transesterification. This biocatalyst can become attractive to the commercial lipases in the process of the kinetic resolution of allyl alcohols.

Immobilized Lipase in the Synthesis of High Purity Medium Chain Diacylglycerols Using a Bubble Column Reactor: Characterization and Application

Novozym^® 435, an immobilized lipase from Candida antarctica B. (CALB), was used as a biocatalyst for the synthesis of high purity medium chain diacylglycerol (MCD) in a bubble column reactor. In this work, the properties of the MCD produced were characterized followed by determining its practical application as an emulsifier in water-in-oil (W/O) emulsion. Two types of MCDs, namely, dicaprylin (C₈-DAG) and dicaprin (C₁₀-DAG), were prepared through enzymatic esterification using the following conditions: 5% Novozym^® 435, 2.5% deionized water, 60°C for 30 min followed by purification. A single-step molecular distillation (MD) (100–140°C, 0.1 Pa, 300 rpm) was performed and comparison was made to that of a double-step purification with MD followed by silica gel column chromatography technique (MD + SGCC). Crude C₈-DAG and C₁₀-DAG with DAG concentration of 41 and 44%, respectively, were obtained via the immobilized enzyme catalyzing reaction. Post-purification via MD, the concentrations of C₈-DAG and C₁₀-DAG were increased to 80 and 83%, respectively. Both MCDs had purity of 99% after the MD + SGCC purification step. Although Novozym^® 435 is a non-specific lipase, higher ratios of 1,3-DAG to 1,2-DAG were acquired. Via MD, the ratios of 1,3-DAG to 1,2-DAG in C₈-DAG and C₁₀-DAG were 5.8:1 and 7.3:1, respectively. MCDs that were purified using MD + SGCC were found to contain 1,3-DAG to 1,2-DAG ratios of 8.8:1 and 9.8:1 in C₈-DAG and C₁₀-DAG, respectively. The crystallization and melting peaks were shifted to higher temperature regions as the purity of the MCD was increased. Dense needle-like crystals were observed in MCDs with high purities. Addition of 5% C₈-DAG and C₁₀-DAG as emulsifier together in the presence of 9% of hydrogenated soybean oil produced stable W/O emulsion with particle size of 18 and 10 μm, respectively.

Thermomyces lanuginosus lipase-catalyzed synthesis of natural flavor esters in a continuous flow microreactor

Enzymatic catalysis is considered to be among the most environmental friendly processes for the synthesis of fine chemicals. In this study, lipase from Thermomyces lanuginosus (Lecitase Ultra™) was used to catalyze the synthesis of flavor esters, i.e., methyl butanoate and methyl benzoate by esterification of the acids with methanol in a microfluidic system. Maximum reaction rates of 195 and 115 mM min⁻¹ corresponding to catalytic efficiencies (k_cat/K_M) of 0.30 and 0.24 min⁻¹ mM⁻¹ as well as yield conversion of 54 and 41 % were observed in methyl butanoate and methyl benzoate synthesis, respectively. Catalytic turnover (k_cat) was higher for methyl butanoate synthesis. Rate of synthesis and yield decreased with increasing flow rates. For both esters, increase in microfluidic flow rate resulted in increased advective transport over molecular diffusion and reaction rate, thus lower conversion. In microfluidic synthesis using T. lanuginosus lipase, the following reaction conditions were 40 °C, flow rate 0.1 mL min⁻¹, and 123 U g⁻¹ enzyme loading found to be the optimum operating limits. The work demonstrated the application of enzyme(s) in a microreactor system for the synthesis of industrially important esters.

Modeling and optimization of phospholipase A₁-catalyzed hydrolysis of phosphatidylcholine using response surface methodology for lysophosphatidylcholine production

Modeling the phospholipase A1 (PLA1 )-catalyzed partial hydrolysis of soy phosphatidylcholine (PC) in hexane for the production of lysophosphatidylcholine (LPC) and optimizing the reaction conditions using response surface methodology were described. The reaction was performed with 4 g of PC in a stirred batch reactor using a commercial PLA1 (Lecitase Ultra) as the biocatalyst. The effects of temperature, reaction time, water content, and enzyme loading on LPC and glycerylphosphorylcholine (GPC) content in the reaction products were elucidated using the models established. Optimal reaction conditions for maximizing the LPC content while suppressing acyl migration, which causes GPC formation, were as follows: temperature, 60°C; reaction time, 3 h; water content, 10% of PC; and enzyme loading, 1% of PC. When the reaction was conducted with 40 g of PC under these conditions, the reaction products contained 83.7 mol % LPC and were free of GPC. LPC had a higher total unsaturated fatty acid content than original PC had and was mainly composed of linoleic acid (78.0 mol % of the total fatty acids).

An insight into the solvent effect on the positional selectivity of the immobilized lipase from Burkholderia cepacia in 1,3-diolein synthesis

The diolein yield was higher while the ratio of 1,3-diolein to 1,2-diolein was smaller in solvents with higher log P values.

Production of novel "functional oil" rich in diglycerides and phytosterol esters with "one-pot" enzymatic transesterification

Diglycerides and phytosterol esters are two important functional lipids. Phytosterol esters mixed with dietary diglyceride could not only influence body weight but also prevent or reverse insulin resistance and hyperlipidemia. In this study, a kind of novel "functional oil" rich in both diglycerides and phytosterol esters was prepared with "one-pot" enzymatic transesterification. First, lipase AYS (Candida rugosa) was immobilized on the porous cross-linked polystyrene resin beads (NKA) via hydrophobic interaction. The resulting immobilized AYS showed much better transesterification activity and thermal stability to freeways. On the basis of the excellent biocatalyst prepared, a method for high-efficiency enzymatic esterification of phytosterols with different triglycerides to produce corresponding functional oils rich in both diglycerides and phytosterol esters was developed. Four functional oils rich in both diglycerides and phytosterol esters with conversions >92.1% and controllable fatty acid composition were obtained under the optimized conditions: 80 mmol/L phytosterols, 160 mmol/L triglycerides, and 25 mg/mL AYS@NKA at 180 rpm and 50 °C for 12 h in hexane. The prepared functional oil possessed low acid value (≤1.0 mgKOH/g), peroxide value (≤2.1 mmol/kg), and conjugated diene value (≤1.96 mmol/kg) and high diglyceride and phytosterol ester contents (≥10.4 and ≥20.2%, respectively). All of the characteristics favored the wide application of the functional oil in different fields of functional food.

Rational synthesis of 1,3-diolein by enzymatic esterification

t-Butanol was an excellent reaction medium for enzyme-mediated esterification of oleic acid with glycerol for 1,3-diolein preparation which has been proved by our group. Herein, to achieve the rational synthesis of 1,3-diolien, response surface methodology was applied to examine the effects of the significant variables and their reciprocal effects on the product synthesis. Under the optimal conditions (62.4°C, 0.75g Novozym 435, substrate molar ratio (oleic acid/glycerol) 2.4 and 4.8g t-butanol), the diolein yield of 87.4% could be achieved, and the value of 1,3-diolien/diolein was as high as 87.8%, which were quite close to the predicted values. Compared with the results of our previous single factor experiment, although the values of diolein yield and 1,3-diolien/diolein could not be improved markedly, the enzyme dosage and the reaction medium were spared by 25% and 20%, respectively, which was a remarkable improvement of the enzymatic process.