Enrichment of omega-3 fatty acids in cod liver oil via alternate solvent winterization and enzymatic interesterification

Enrichment of C17:0-rich saturated fatty acids from sheep tail fat for adjuvant therapy of non-small-cell lung cancer

Heptadecanoic acid (C17:0), an odd-chain saturated fatty acid (OCSFA) in ruminant lipid, has been demonstrated to be potential for treating cancers. Our results also showed that sheep tail fat (STF) with higher level of C17:0-containing saturated fatty acids (SFAs) whereas lower level of oleic acid (C18:1), performed remarkable inhibition against non-small-cell lung cancer (NSCLC) cells. To enrich the content of C17:0, a C17:0-rich SFA concentrate (HRSC) was prepared from STF by solvent crystallization and urea complexation methods (hexane/STF = 3.5/1, 4 °C for 8 h, and 80% ethanol/urea/free fatty acids = 8/1/1, 4 °C for 6 h). The content of C17:0 was up from 3.02 to 6.34% and the recovery was 4.17%. Biological experiments showed that HRSC exerted better antiproliferative effect against NSCLC cells. Moreover, HRSC performed enhanced inhibitory effect in A549 cell xenograft mouse model. Therefore, HRSC has the potential to be applied in adjuvant therapy for NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01504-w.

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

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

Highly Valuable Fish Oil: Formation Process, Enrichment, Subsequent Utilization, and Storage of Eicosapentaenoic Acid Ethyl Esters

In recent years, as the demand for precision nutrition is continuously increasing, scientific studies have shown that high-purity eicosapentaenoic acid ethyl ester (EPA-EE) functions more efficiently than mixed omega-3 polyunsaturated fatty acid preparations in diseases such as hyperlipidemia, heart disease, major depression, and heart disease; therefore, the market demand for EPA-EE is growing by the day. In this paper, we attempt to review EPA-EE from a whole-manufacturing-chain perspective. First, the extraction, refining, and ethanolysis processes (fish oil and ethanol undergo transesterification) of EPA-EE are described, emphasizing the potential of green substitute technologies. Then, the method of EPA enrichment is thoroughly detailed, the pros and cons of different methods are compared, and current developments in monomer production techniques are addressed. Finally, a summary of current advanced strategies for dealing with the low oxidative stability and low bioavailability of EPA-EE is presented. In conclusion, understanding the entire production process of EPA-EE will enable us to govern each step from a macro perspective and accomplish the best use of EPA-EE in a more cost-effective and environmentally friendly way.

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.

Progress in enrichment of n-3 polyunsaturated fatty acid: a review

n-3 Polyunsaturated fatty acids (n-3 PUFA) has been widely used in foods, and pharmaceutical products due to its beneficial effects. The content of n-3 PUFA in natural oils is usually low, which decreases its added value. Thus, there is an increasing demand on the market for n-3 PUFA concentrates. This review firstly introduces the differences in bioavailability and oxidative stability between different types of PUFA concentrate (free fatty acid, ethyl ester and acylglycerol), and then provides a comprehensive discussion of different methods for enrichment of lipids with n-3 PUFA including physical-chemical methods and enzymatic methods. Lipases used for catalyzing esterification, transesterification and hydrolysis reactions play an important role in the production of highly enriched various types of n-3 PUFA concentrates. Lipase-catalyzed alcoholysis or hydrolysis reactions are the mostly employed method to prepare high-quality n-3 PUFA of structural acylglycerols. Although many important advantages offered by lipases in enrichment of n-3 PUFA, the high cost of enzyme limits its industrial-scale production. Further research should focus on looking for biological enzymes with extraordinary catalytic ability and clear selectivity. Other novel technologies such as protein engineering and immobilization may be needed to modify lipases to improve its selectivity, catalytic ability and reuse.

Enrichment of Palmitoleic Acid by a Combination of Two-step Solvent Crystallization and Molecular Distillation

Palmitoleic acid shows a variety of beneficial properties to human health. In this study, enrichment of palmitoleic acid from sea buckthorn pulp oil by two-step solvent crystallization and molecular distillation was investigated. Sea buckthorn pulp oil was first converted to its corresponding mixed fatty acids (SPOMFs) containing 27.17% palmitoleic acid. Subsequently, the effects of various factors on crystallization (i.e., crystallization temperature, type of solvent, ratio of SPOMFs to solvent (w/v), crystallization time) and molecular distillation (distillation temperature) were assessed on a 5-g scale. It was found that optimal primary crystallization conditions were a 1:15 ratio of SPOMFs to methanol (w/v), -20°C and 12 h. Secondary crystallization conditions were set to a 1:4 ratio of methanol to palmitoleic acid product obtained from the first step crystallization to methanol (w/v), -40°C and 6 h. For further purification of palmitoleic acid by molecular distillation, the optimal distillation temperature was determined to be 100°C. After purification by crystallization and molecular distillation under the optimal conditions, the final product consisted of 54.18% palmitoleic acid with an overall yield of 56.31%. This method has great potential for adoption by the food and medical industries for the preparation of palmitoleic acid concentrate for nutritional studies.

Sustainable synthesis of branched-chain diesters

Esters from branched alcohols and dicarboxylic linear acids are widely used as lube bases due to their good performance at low temperatures. This work proposes a new process to synthesize bis(2-ethylbutyl) adipate and bis(2-ethylbutyl) sebacate by using the lipase-based catalyst Novozym® 435 in a solvent-free system. Different reaction strategies have been tested in order to minimize 2-ethyl-1-butanol losses due to its evaporation and optimum operation conditions have been determined: 2.5 % of biocatalyst, 50 °C and a molar excess of alcohol of 15 % for the adipic diester and of 25 % for the sebacic one. It has also been proven that the immobilized enzyme can be reused in seven successive reaction cycles, achieving high yields without an appreciable reduction of activity. This biocatalytic pathway is a promising basis for the development of a more sustainable large scale process for obtaining biodegradable lubricants, as it is pointed out by productivity, economic and green metrics calculations.

Phospholipid-Protein Structured Membrane for Microencapsulation of DHA Oil and Evaluation of Its In Vitro Digestibility: Inspired by Milk Fat Globule Membrane

The present study aims to design a milk fat globule membrane (MFGM)-inspired structured membrane (phospholipid- and protein-rich) for microencapsulation of docosahexaenoic acid (DHA) oil. DHA-enriched oil emulsions were prepared using different ratios of sunflower phospholipid (SPL), proteins [whey protein concentrate (WPC), soy protein isolate (SPI), and sodium caseinate (SC)], and maltodextrin and spray-dried to obtain DHA microcapsules. The prepared DHA oil emulsions have nanosized particles. SPLs were found to affect the secondary structure of WPC, which resulted in increased exposure of the protein hydrophobic site and emulsion stability. SPL also reduced the surface tension and viscosity of the DHA oil emulsions. In vitro digestion of the spray-dried DHA microcapsules showed that they were able to effectively resist gastric proteolysis and protect their bioactivity en route to the intestine. The DHA microcapsules have a high lipid digestibility in the small intestine with a high DHA hydrolysis efficiency (74.3%), which is higher than that of commercial DHA microcapsules.

An Overview of Potential Oleaginous Microorganisms and Their Role in Biodiesel and Omega-3 Fatty Acid-Based Industries

Microorganisms are known to be natural oil producers in their cellular compartments. Microorganisms that accumulate more than 20% w/w of lipids on a cell dry weight basis are considered as oleaginous microorganisms. These are capable of synthesizing vast majority of fatty acids from short hydrocarbonated chain (C6) to long hydrocarbonated chain (C36), which may be saturated (SFA), monounsaturated (MUFA), or polyunsaturated fatty acids (PUFA), depending on the presence and number of double bonds in hydrocarbonated chains. Depending on the fatty acid profile, the oils obtained from oleaginous microorganisms are utilized as feedstock for either biodiesel production or as nutraceuticals. Mainly microalgae, bacteria, and yeasts are involved in the production of biodiesel, whereas thraustochytrids, fungi, and some of the microalgae are well known to be producers of very long-chain PUFA (omega-3 fatty acids). In this review article, the type of oleaginous microorganisms and their expertise in the field of biodiesel or omega-3 fatty acids, advances in metabolic engineering tools for enhanced lipid accumulation, upstream and downstream processing of lipids, including purification of biodiesel and concentration of omega-3 fatty acids are reviewed.

Comparison of fish and oil supplements for a better understanding of the role of fat level and other food constituents in determining bioaccessibility

In order to investigate the effects of fat level and protein and other components on lipid bioaccessibility, the bioaccessibility of total lipids and particular fatty acids (FAs) of fish samples with different fat levels (5.4% w/w, 10.2% w/w, and 16.6% w/w) and cod liver oil supplement in different quantities (82, 154, 313, 604, and 1,027 mg) was determined by an in vitro digestion model. Digestion of the fish and oil (up to 154 mg) samples as measured by TAG disappearance was complete. Lipolysis was impaired by high amounts of oil (313 mg and higher). Bioaccessible FA profiles had similarities with the initial (before digestion) FA profiles. However, total MUFA and oleic acid contents were higher in the bioaccessible fraction. The bioaccessibility of EPA and DHA was generally lower than that of oleic acid and total MUFA. Fat level did not affect FAs' bioaccessibility. On the other hand, protein and other components may have interfered in lipid bioaccessibility and it was found that the reduction of bioaccessibility was stronger when the ratio of the lipid fraction to the nonlipid fraction (mainly protein) was smaller.

Highly Efficient and Enzyme-Recoverable Method for Enzymatic Concentrating Omega-3 Fatty Acids Generated by Hydrolysis of Fish Oil in a Substrate-Constituted Three-Liquid-Phase System

A novel three-liquid-phase system which contained fish oil as the nonpolar phase was developed for the lipase-based hydrolysis of fish oil and subsequent enrichment of the omega-3 polyunsaturated fatty acids (n-3 PUFA) in the glyceride fraction of the fish oil. In comparison with the traditional oil/water system, the enrichment factor of n-3 PUFA in this system was increased by 363.4% as a result of a higher dispersity, higher selectivity of the lipase for the other fatty acids except for n-3PUFA, and relief of product inhibition. The content of n-3 PUFA in the glyceride fraction could be concentrated to 67.97% by repeated hydrolysis after removing the free fatty acids. Furthermore, the lipase could be reused for at least eight rounds. This method would be an ideal approach for enriching n-3 PUFA because it is cost-effective, low in toxicity, and easily scaled up.

Decrease in the Level of Nervonic Acid and Increased Gamma Linolenic Acid in the Plasma of Women with Polycystic Ovary Syndrome after a Three-month Low-glycaemic Index and Caloric Reduction Diet

The aetiology of polycystic ovary syndrome (PCOS) remains uncertain and thus dedicated studies are still of much importance. Patients in this group are at high risk for metabolic syndrome, diabetes and ischemic heart disease. Our goal was to use a dietary intervention, facilitating the regression of the disease, through the observation of lipid and hormonal profiles, carbohydrate metabolic parameters and metabolomics of plasma fatty acids. There were 39 Caucasian women with PCOS aged 26.76 ±5.08 that qualified for this study. Fatty acid profiles were investigated using gas chromatography. The results of plasma fatty acids were compared with the initial results and the control group. A three-month caloric reduction diet with low glycemic index (GI) reduces the level of nervonic acid and is a great alternative in PCOS therapy. The introduction of rapeseed oil and olive oil to the lowered GI reduction diet caused the increase in the ratio of average length chain fatty acids (C10:0, C14:0) and the enhancement of synthesis pathways for pentadecanoic acid (C15:0) and gamma-linolenic acid (GLA, C18:3n-6), but did not inhibit the synthesis of the derivatives of arachidic acid (C20:0). Additionally, a decrease in the level of nervonic acid (C24:1) was observed. Biochemical analysis of blood showed the improvement of plasma lipid fractions, but a significant reduction of androgen levels was not observed. A reduction diet with lowered GI lead to many positive effects in the improvement of the biochemical parameters of women with PCOS. It should be continued for a prolonged period of time, until the synthesis pathways for inflammatory factors are silenced.

Lipase-catalyzed selective enrichment of omega-3 polyunsaturated fatty acids in acylglycerols of cod liver and linseed oils: Modeling the binding affinity of lipases and fatty acids

Present study employed molecular modeling method to elucidate the binding affinity of lipases with fatty acids of different chain lengths; and investigated the effects of lipases positional and fatty acids specificity on omega-3 polyunsaturated fatty acids (ω-3 PUFAs) enrichment in cod liver and linseed oils. Among the lipases studied, molecular modeling showed the active sites of Candida rugosa lipase (CRL) had a low C-Docker interactive energy for saturated (SFA) and monounsaturated (MUFA) fatty acids which predicted CRL to have highest preferences to selectively hydrolyze resulting in efficient enrichment of ω-3 PUFAs. Verification experiments showed the SFA and MUFA in the acylglycerol fraction includes monoacylglcyerols (MAG), diacyglycerols (DAG), and triacylglycerols (TAG) of CRL-hydrolyzed cod liver oil decreased from the initial 25.21 to 16.88% and 45.25 to 32.17%, respectively. In addition, CRL-hydrolyzed cod liver oil demonstrated 88.36% of ω-3 PUFAs enrichment. The regio-distribution of fatty acids in CRL-hydrolyzed cod liver oil were not significantly different than that of cod liver oil indicating the ω-3 PUFAs enrichment was due to fatty acids selectivity and not positional selectivity of CRL.

Synthesis of docosapentaenoic acid-enriched diacylglycerols by enzymatic glycerolysis of Schizochytrium sp. oil

Utilization of algae oil and glycerol for preparation of value-added products is vital for sustainable development of related industries. In this study, we aimed to prepare highly pure diacylglycerols (DAG) rich in docosapentaenoic acid (DPA). First, content of DPA in form of triacylglycerols (TAG) increased from 16.4% to 28.1% after low-temperature crystallization of Schizochytrium sp. oil at -80 °C for 6 h. Subsequently, DPA-enriched DAG was prepared by the enzymatic glycerolysis of the enriched oil. Under the optimum conditions, there was 48.4% DAG produced in the crude mixture. To remove polar impurities from the crude product, a novel two-step purification was developed and the final product consisted of 75.1% DAG and 24.9% TAG with a low peroxide value. The current method for the synthesis of DAG rich DPA is effective and relatively mild and the successful preparation of value-added product will reduce production costs for algae and biodiesel industries.