Optimization of the Synthesis of Structured Phosphatidylcholine with Medium Chain Fatty Acid

Highly effective synthesis of novel structured phospholipid emulsifiers using magnetically recyclable Fe3O4@SiO2/M (M = Zn or Al) composite

It is of great importance to develop a most efficient, recyclable, and ecofriendly process to produce novel structured phospholipid emulsifiers. Herein, innovative medium-chain structured phospholipid (MCSPL) emulsifiers were synthesized through transesterification of soybean lecithins with medium-chain fatty acids (MCFAs) promoted by Zn- or Al-incorporated Fe3O4@SiO2, denoted by Fe3O4@SiO2/M (M = Zn or Al). Resultingly, Fe3O4@SiO2/M (M = Zn or Al) exhibited the most superior reactivity with 97.1% or 88.7% MCFA incorporation to other benchmark catalysts and also had excellent magnetic separability and recyclability. Noticeably, targeted MCSPLs possessed almost more superior emulsifying properties to other phospholipid emulsifiers, and had potential for use as oil-in-water emulsifiers. Conclusively, the present findings demonstrate that transesterification promoted by Fe3O4@SiO2/M (M = Zn or Al) can be a promising approach for green, economic, and highly effective synthesis of novel dual-function phospholipid emulsifiers with bioactive and emulsifying properties in food, pharmaceutical, and cosmetic industries.

Design and simulation of a caprylic acid enzymatically modified phosphatidylcholine micelle using a coarse-grained molecular dynamics simulations approach

Computationally simulated micelle models provide useful structural information on the molecular and biological sciences. One strategy to study the self-aggregation process of surfactant molecules that make up a micelle is through molecular dynamics (MD) simulations. In this study, a theoretical approach with a coarse-grained MD simulation (CG-MD) was employed to evaluate the critical micellar concentration (CMC), the micellization process, building a tridimensional (3D) model system of a micelle using data from the experimentally enzymatically modified phospholipids (PL) by phospholipase A1 (PA1). This required enzymatic interesterification of soybean phosphatidylcholine (PC) with caprylic acid, along with purification and characterization by chromatographic techniques to measure the esterified fatty acids and the corresponding PL composition. The number of molecules used in the CG-MD simulation system was determined from the experimental CMC data which was 0.025%. The molecular composition of the system is: 1 C 18:2, 2 C 8:0/8:0, 3 C 8:0/18:3n-9, 4 C 8:0/18:0, 5 C8:0/18:2n-6, 6 C8:0/18:1n-9, and 7 C 8:0/16:0. According to our theoretical results, the micelle model is structurally stable with an average Rg of 3.64 ± 0.10 Å, and might have an elliptical form with a radius of 24.6 Å. Regarding CMC value there was a relationship between the experimental data of the modified PLs and the theoretical analysis by GC-MD, which suggest that the enzymatic modification of PLs does not affect their self-aggregation properties. Finally, the micellar system obtained in the current research can be used as a simple and useful model to design optimal biocompatible nanoemulsions as possible vehicles for bioactive small molecules.Communicated by Ramaswamy H. Sarma.

Acidolysis of phospholipids with medium-chain fatty acids over M-SBA-15 (M = Zn, Al) silicas as efficient solid catalysts

BACKGROUND

Efficient and sustainable production of structured phospholipids (SPLs) enriched in medium-chain fatty acids (MCFAs) in a heterogeneous manner is crucial for their potential applications in functional foods and drugs. Herein, for the first time, Zn- and Al-incorporated SBA-15 silicas were prepared by the coprecipitation method and further researched for catalytic synthesis of MCFA-enriched SPLs through acidolysis reaction of natural phospholipids with capric or caprylic acid.

RESULTS

The as-prepared Zn- and Al-incorporated SBA-15 samples exhibited superior catalytic activities under mild experimental conditions (50 °C, 6 h) to commercial homogeneous Lewis acids and benchmark enzymes. Correspondingly, the capric acid and caprylic acid incorporations were respectively achieved up to ~40.25 ± 0.40% (or 35.08 ± 0.09%) and 37.26 ± 0.38% (or 33.02 ± 0.13%) for Zn- (or Al-) incorporated SBA-15 catalyst. Moreover, various methods such as scanning electron microscopy with energy-dispersive X-ray spectrometry, ultraviolet-visible diffuse reflectance spectroscopy and pyridine-Fourier transform infrared spectroscopy were utilized to characterize the two catalysts in order to elucidate the possible structure-performance relationship. Accordingly, the above-mentioned satisfactory results are most probably due to the well-ordered mesostructures and large amounts of active Lewis acid sites existing in the investigated materials. Noticeably, the two catalysts featured good separation and excellent recyclability as well.

CONCLUSION

The Zn- and Al-incorporated SBA-15 catalysts studied in this work might shed light on novel, sustainable and economic alternatives for effective SPL production to diminish the applications of conventional homogeneous catalysts and biocatalysts in food industries. © 2022 Society of Chemical Industry.

Progress & Prospect of Enzyme-Mediated Structured Phospholipids Preparation

In recent years, structured phospholipids (SPLs), which are modified phospholipids (PLs), have attracted more attention due to their great potential for application in the field of pharmacy, food, cosmetics, and health. SPLs not only possess enhanced chemical, physical and nutritional properties, but also present superior bioavailability in comparison with other lipid forms, such as triacylglycerols, which make SPLs become more competitive carriers to increase the absorption of the specific fatty acids in the body. Compared with chemical-mediated SPLs, the process of enzyme-mediated SPLs has the advantages of high product variety, high substrate selectivity, and mild operation conditions. Both lipases and phospholipases can be used in the enzymatic production of SPLs, and the main reaction type contains esterification, acidolysis, and transesterification. During the preparation, reaction medium, acyl migration, water content/activity, substrates and enzymes, and some other parameters have significant effects on the production and purity of the desired PLs products. In this paper, the progress in enzymatic modification of PLs over the last 20 years is reviewed. Reaction types and characteristic parameters are summarized in detail and the parameters affecting acyl migration are first discussed to give the inspiration to optimize the enzyme-mediated SPLs preparation. To expand the application of enzyme-mediated SPLs in the future, the prospect of further study on SPLs is also proposed at the end of the paper.

Prolongation of secondary drying step of phospholipid lyophilization greatly improves acidolysis reactions catalyzed by immobilized lecitase ultra

Conjugated linolenic acid (CLA) has important health effects, and their phospholipids forms (PL) are advantageous vehicles of this bioactive agent. Acidolysis of soybean phosphatidylcholine (PC) with conjugated linolenic acid (CLA) catalyzed by Lecitase® Ultra immobilized on Duolite A658 was studied. This reaction is typically limited by hydrolysis, producing 60-90 % of lyso- and glycero-PC and yielding low the process efficiency. Drying the amphiphilic PC material was found the key factor for maximal diacylglycerol phosphatidylcholines (PC) production and different drying approaches were studied to maximize the formation of PC rich in CLA in a solvent free process. PC lyophilization for 24 h getting dry solid appearance (PC; 783 ± 11 mg water/Kg PC) or other standard protocols to reduce water content/activity of reaction medium, did not improve the reaction performance. However, adding 4 extra days to the second step of lyophilization at high vacuum (1 Pa) and moderate temperature (20 °C), followed by further PC dehydration with molecular sieves, drastically reduced the hydrolysis process by achieving a extensive PC dehydration (279 ± 4 mg water/Kg PC), obtaining for the first time >99% molar yield of diacyl-PC product. After 24 h of reaction, a diacyl-PC product with 72.3% CLA content was obtained. PC molecules containing two CLA were the major species formed.

Lipase Catalyzed Acidolysis for Efficient Synthesis of Phospholipids Enriched with Isomerically Pure cis-9,trans-11 and trans-10,cis-12 Conjugated Linoleic Acid

The production of phospholipid (PL) conjugates with biologically active compounds is nowadays an extensively employed approach. This type of phospholipids conjugates could improve bioavailability of many poorly absorbed active compounds such as isomers of conjugated linoleic acid (CLA), which exhibit versatile biological effects. The studies were carried out to elaborate an efficient enzymatic method for the synthesis of phospholipids with pure (>90%) cis-9,trans-11 and trans-10,cis-12 CLA isomers. For this purpose, three commercially available immobilized lipases were examined in respect to specificity towards CLA isomers in acidolysis of egg-yolk phosphatidylcholine (PC). Different incorporation rates were observed for the individual CLA isomers. Under optimal conditions: PC/CLA molar ratio 1:6; Rhizomucor miehei lipase loading 24% wt. based on substrates; heptane; DMF, 5% (v/v); water activity (aw), 0.11; 45 °C; magnetic stirring, 300 rpm; 48 h., effective incorporation (EINC) of CLA isomers into PC reached ca. 50%. The EINC of CLA isomers was elevated for 25–30% only by adding a water mimic (DMF) and reducing aw to 0.11 comparing to the reaction system performed at aw = 0.23. The developed method of phosphatidylcholine acidolysis is the first described in the literature dealing with isometrically pure CLA and allow to obtain very high effective incorporation.