Intake of different eicosapentaenoic acid-containing lipids and fatty acid pattern of plasma lipids in the rats

The ethyl ester of eicosapentaenoic acid (EPA) is the only pure EPA-containing lipid available in bulk for oral administration. However, there is doubt as to whether EPA ethyl ester can efficiently increase the plasma levels of EPA in comparison with the ability of other kinds of EPA-containing lipids to do so. Therefore, two other kinds of EPA-containing lipids were prepared to study the efficiency of oral administration of those lipids for increasing the EPA content in plasma phospholipids and cholesteryl esters. EPA-containing lipids which were investigated were [A], 1,2,3-trieicosapentaenoyl-glycerol, [B] 2-eicosapentaenoyl-phosphatidylcholine and [C] ethyl ester of EPA. An adjusted amount of lipids [A], [B] and [C] was administered to rats through a gastric tube for 4 days (the first experiment) or for 10 days (the second experiment), and the fatty acid composition of plasma phospholipids and cholesteryl esters was determined. In the first experiment, there were no significant differences in the efficiency for increasing EPA levels in either phospholipids or cholesteryl esters among the lipids. In the second experiment, the EPA levels of both plasma phospholipids and cholesteryl esters of rats administered ethyl ester of EPA were significantly higher than those of rats administered 2-eicosapentaenoyl-phosphatidylcholine. The EPA levels of the rats administered 1,2,3-trieicosapentaenoylglycerol were between the levels of the two groups mentioned above, but the differences in the EPA levels were not significant. Although an ethyl ester-type molecule is not a naturally occurring lipid, ethyl ester of EPA is equal to 1,2,3-trieicosapentaenoyl-glycerol and appears to be superior to 2-eicosapentaenoyl-phosphatidylcholine as to the efficiency for increasing EPA levels in total plasma phospholipids and plasma cholesteryl esters.     

Analysis of Intact Cholesteryl Esters of Furan Fatty Acids in Cod Liver

Furan fatty acids (F‐acids) are a class of natural antioxidants with a furan moiety in the acyl chain. These minor fatty acids have been reported to occur with high proportions in the cholesteryl ester fraction of fish livers. Here we present a method for the direct analysis of intact cholesteryl esters with F‐acids and other fatty acids in cod liver lipids. For this purpose, the cholesteryl ester fraction was isolated by solid phase extraction (SPE) and subsequently analyzed by gas chromatography with mass spectrometry (GC/MS) using a cool‐on‐column inlet. Pentadecanoic acid esterified with cholesterol was used as an internal standard. GC/MS spectra of F‐acid cholesteryl esters featured the molecular ion along with characteristic fragment ions for both the cholesterol and the F‐acid moiety. All investigated cod liver samples (n = 8) showed cholesteryl esters of F‐acids and, to a lower degree, of conventional fatty acids. By means of GC/MS‐SIM up to ten F‐acid cholesteryl esters could be determined in the samples. The concentrations of cholesteryl esters with conventional fatty acids amounted to 78–140 mg/100 g lipids (mean 97 mg/100 g lipids), while F‐acid cholesteryl esters were present at 47–270 mg/100 g lipids (mean 130 mg/100 g lipids).     

The result of feeding palmitoyl glycerol on lymph and plasma lipids

Palmitoyl glycerol is toxic when fed to mice, but the toxicity is alleviated by supplementing the toxic diet with 2–4% oleate or linoleate at the expense of sucrose. Lipid and fatty acid composition of lymph and plasma were studied in mice fed chow and palmitoyl glycerol diets to help explain the toxicity mechanism. When mice were fed chow, intestinal lymph contained a high proportion of saturated fatty acids; when they were given palmitoyl glycerol, the proportion approached 90% saturated fatty acids. The cholesteryl ester fraction was higher in lymph from mice fed a toxic diet than when the diet was fortified with supplemental safflower oil. However, there were no differences between diets in lipid composition of blood plasma. Similarly, except for plasma cholesterol esters, there were no differences in fatty acid composition between mice fed palmitoyl glycerol as the only fat or supplemented with a protective unsaturated fat. In the plasma, cholesteryl palmitate was elevated and cholesteryl oleate and cholesteryl linoleate were depressed when mice were given a toxic diet. Although a monoacylglycerol was toxic when fed, the percentages of monoacylglycerols in lymph or plasma were not materially elevated. The findings indicate that neither the total proportion of saturated fatty acids nor the amount of circulating monoacylglycerols was directly involved in the toxicity of palmitoyl glycerol.     

A unique lipid pattern associated with the gall bladder bile of the chick embryo

A study has been made of the lipid and fatty acid composition of the gall bladder bile of the chick embryo during the last week of incubation. The lipids and their fatty acid composition showed a unique pattern when compared to other animal species. Of the total lipid present, phospholipid accounted for less than half, and there were substantial proportions of both cholesteryl ester and triglyceride. In the cholesteryl ester, the proportion of which increased significantly over the last week of incubation, there was a very high level of oleic acid. The phospholipid contained a high level of arachidonic acid. The results are discussed in relation to observations on the biliary lipids of other animal species and the major features of the lipid metabolism of the chick embryo during the last week of incubation.     

Cholesterol esterification and cholesteryl ester hydrolysis by rabbit and human ovaries

Esterification of cholesterol occurred in vitro in rabbit and human ovaries via an acyl CoA-cholesterolO-acyltransferase reaction. The rate of esterification was increased in early pregnancy and may be one of the mechanisms whereby the content of stored ovarian cholesteryl esters is increased during this period. The increased cholesteryl esters were primarily in the form of cholesteryl oleate. The cholesteryl ester fatty acid patterns in both rabbit and human ovaries differed from those in sera, suggesting that a significant portion of these esters may have been derived from in situ synthesis. The rate of hydrolysis of cholesteryl esters during pregnancy was also increased, and occurred at a faster in vitro rate than esterification. Of the agents tested, only soy lecithin was found to significantly enhance the rate of hydrolysis of cholesteryl oleate by ovarian homogenates.     

Cholesteryl ester compounds containing alkyl branched acyl groups — their preparations,properties and applications

Cholesterol having a reactive hydroxyl group at C₃-position can react with fatty acids to give the corresponding cholesteryl esters. Most of the natural cholesteryl esters consist of straight alkyl chain fatty acids with a high melting point. In oleochemistry it is well known that alkyl branched fatty acids, which are derived from petroleum or the fat and oil industry, have low melting points (mp.) and are chemically more stable if they are saturated acids. We designed alkyl branched fatty acid cholesteryl esters by means of common esterification and found some esters having a low mp. (mostly as a liquid). They had no irritative effect on both animal and human skin. They showed characteristic emulsification properties, namely the formation of either O/W or W/O emulsion coexistence together with other lipid components. Applying them onto human skin, they were able to penetrate towards the stratum corneum and improve the water-retaining ability and the barrier function of the stratum corneum. Based on these properties we have been applying the alkyl branched fatty acid cholesteryl ester, especially the methyl branched isostearic acid cholesteryl ester (IS-CE), to a shampoo and a rinse as hair cosmetics, skin care cosmetics and bath-additive products in the past decade.     

Effects of dietary saturated andtrans fatty acids on cholesteryl ester synthesis and hydrolysis in the testes of rats

Studies were made of the enzymic synthesis and hydrolysis of cholesteryl esters in rat testes. Weanling rats were fed for 14 weeks diets containing 5% by wt of hydrogenated coconut oil (HCO), a concentrate of ethyl elaidate and linolelaidate (TRANS), devoid of essential fatty acids (EFA), or safflower oil (SAFF). Cholesterol esterifying activity was localized in the soluble fraction, and cholesteryl ester hydrolase activity was distributed in both particulate and soluble fractions obtained from tissue homogenates. The optimum pH was 6.0 for esterification and 6.9–7.0 for hydrolysis. Neither esterifying nor hydrolytic activity was affected by freezing and thawing, but both reactions were inhibited by heat or sonication. The animals of both the HCO and TRANS groups had developed an EFA deficiency before they were sacrificed. The EFA deficiency produced upon feeding the HCO diet had no apparent effect on the synthesis and hydrolysis of cholesteryl esters in rat testes. The TRANS diet influenced the development of the testes as judged by their size, and cholesterol esterifying and cholesteryl ester hydrolyzing activities were suppressed in the testes of the animals of this group. A major difference in the effects of the HCO and TRANS diets on the lipids of the testes was the relatively minor amount of eicosatrienoic acid (20∶3) and the elevated level of docosapentaenoic acid (22∶5) in the cholesteryl esters of the testicular lipids of the TRANS group.     

Effects on plasma lipids and fatty acid composition of very low fat diets enriched with fish or kangaroo meat

The effects of very low fat diets (<7% energy) enriched with different sources of long chain (C20 and C22) polyunsaturated fatty acids (PUFA) on plasma lipid levels and plasma fatty acids (PUFA) on plasma lipid levels and plasma fatty acid composition were studied in 13 healthy volunteers. Three diets provided 500 g/day of tropical Australian fish (rich in arachidonic acid and docosahexaenoic acid), southern Australian fish (rich in docosahexaenoic acid) or kangaroo meat (rich in linoleic and arachidonic acids). The fourth diet was vegetarian, similarly low in fat but containing no 20- and 22-carbon PUFA. Subjects ate their normal or usual diets on weeks 1 and 4 and the very low fat diets in weeks 2 and 3. Weighed food intake records were kept, and weeks 2, 3 and 4 were designed to be isoenergetic with week 1. Plasma cholesterol levels fell significantly on all diets within one week. There were reductions in both low density (LDL) and high density lipoprotein (HDL) cholesterol levels, with effects on HDL cholesterol being more consistent. There were no consistent or significant effects on total triglyceride levels despite the high carbohydrate content of the diets. On all diets the percentage of linoleic acid fell in the plasma phospholipid and cholesteryl ester fractions, while the percentage of palmitic acid in the phospholipids and cholesteryl esters and palmitoleic acid in the cholesteryl ester fraction rose on all diets. The percentage of arachidonic acid rose in the phospholipid and cholesteryl esters on the two diets that were good sources of this fatty acid (tropical fish and kangaroo meat). The percentage of docosahexaenoic acid also rose on the two diets that were the richest sources of this fatty acid (the fish diets), and the percentage of eicosapentaenoic acid rose in the phospholipid and cholesteryl esters in proportion to the dietary level of this fatty acid (southern fish > kangaroo > tropical fish). The changes in fatty acid composition were almost completely reversed within seven days of returning to the usual higher fat diets.     

Fatty acid composition of tissue lipids from miniature swine: Influence of dietary sucrose and starch

The fatty acid composition of serum, liver and adipose tissue from Pitman-Moore miniature swine was determined following their consumption of starch- or sucrose-containing diets for a period of one year. Among the tissues studied there were no significant differences in the fatty acid composition due to the type of dietary carbohydrate (starch or sucrose). The cholesteryl ester fatty acid composition of all samples studied remained quite constant. There were minor fluctuations in fatty acid composition of phospholipids and triglycerides from serum collected at diferent intervals following initiation of the diets.     

Synthesis of cholesterol esters in the plasma and liver of sheep

A study was made with sheep on the formation in vitro of long chain fatty acid esters of cholesterol by the lecithin-cholesterol-acyltransferase system present in the plasma and the acyl CoA-cholesterol-acyltransferase system present in the liver. The rate of cholesterol esterification in the plasma was 0.024 μmoles/ml/hr. The relative pattern of fatty acids esterified during incubation of the plasma remained constant over the 8 hr period of incubation and was similar to the fatty acids in the plasma cholesteryl esters before incubation began and to the fatty acids in the 2-position of the plasma lecithin. The predominant cholesteryl esters synthesized contained monoenoic and dienoic fatty acids. Unlike the bovine, there was no apparent discrimination in favor of the 18∶2 containing species of plasma lecithin as donors of fatty acids. This difference could be accounted for by the similarity in the 18∶2 content of the phospholipids present in the high density (density >1.062 and < 1.21) and the low density (density > 1.006 and <1.063) lipoprotein fractions of the sheep plasma. The possibility of some discrimination against 20∶4 during cholesterol ester synthesis in the plasma of the sheep cannot be excluded. In the liver, the predominant cholesteryl esters synthesized contained saturated and monoenoic fatty acids; cholesteryl linoleate was synthesized to a very much less extent. There was considerable similarity between the composition of the unesterified fatty acid fraction of the liver before incubation began and the fatty acid composition of the cholesteryl esters synthesized during incubation. Addition of sonicated suspensions of free fatty acids altered markedly the fatty acid pattern of the cholesteryl esters synthesized by the liver slices. From the evidence presented it is concluded that the cholesteryl esters in sheep plasma are syntheized mainly by the plasma lecithin-cholesterol-acyltransferase system. The results are discussed in relation to cholesterol esterification systems demonstrated in the plasma and liver of monogastric animals.     

Cholesteryl ester hydrolase activity in adrenal homogenates from normal and essential fatty acid-deficient female rats

Cholesteryl ester hydrolase was assayed in adrenal homogenates from mature female rats fed a control (corn oil-containing) or essential fatty acid (EFA)-deficient diet. Cholesteryl ester of 16∶0, 18∶0, 18∶1, 18∶2(n−6), 20∶4(n−6) and 22∶4(n−6) were used as substrates. In control rats, the unsaturated esters were hydrolyzed more rapidly than the saturated esters and cholesteryl arachidonate was the preferred substrate of the six investigated; cholesteryl oleate elicited the highest activity in the deficient group. Polyunsaturated esters were hydrolyzed at a significantly lower rate by homogenates from EFA-deficient rats than by those from control animals. The esters of 18∶1, 18∶2(n−6) and 20∶4(n−6) were hydrolyzed more extenstively in relation to their concentrations in adrenal tissue than were cholesteryl esters of 16∶0, 18∶0 and 22∶4(n−6). This difference was more pronounced in control than in EFA-deficient rats. No simple relationship of adrenal cholesteryl ester hydrolase activity to ester fatty acid structure or to nutritional essentiality was evident.     

Synthesis of spin-labeled neutral lipids: Nitroxyl derivatives of triglycerides and sterol esters

Methods for the preparation of useful spin-labeled neutral lipids are described. A spin-labeled triglyceride has been prepared by acylation of 1,3-distearoylglycerol with stearic acid anhydride bearing the 4′,4′-dimethyloxazolidine-N-oxyl ring at carbon-12. The same fatty acid anhydride has been used to acylate the 3-hydroxy group of cholesterol to obtain a cholesteryl ester with the nitroxyl function in the fatty acyl chain. The 4′,4′-dimethyloxazolidinyl-1-oxyl derivative of 5α-an drostan-3-one-17β-ol has been esterified with stearic acid anhydride to obtain a steroid ester with the paramagnetic center in the steroid nucleus.     

Synthesis of saturated,unsaturated, spin-labeled,and fluorescent cholesteryl esters: Acylation of cholesterol using fatty acid anhydride and 4-pyrrolidinopyridine

A rapid, high yield method for the preparation of cholesteryl esters is described. The method is a modification of the catalytic procedure previously applied to the acylation of sn-glycero-3-phosphoryl-choline (Patel, K.M., J.D. Morrisett, and J.T. Sparrow, J. Lipid Res., 20:676 (1979). Cholesteryl esters are formed in excellent yield by acylating cholesterol with fatty acid anhydride or fatty acid and dicyclohexylcarbodiimide in methylene chloride containing 4-pyrrolidinopyridine. The versatility of the method is demonstrated by the preparation of the cholesteryl esters of saturated, unsaturated, spinlabeled, and labile fluorescent fatty acids.     

Preparation of fatty acid methyl esters from lipoprotein and macrophage lipid subclasses on thin-layer plates

A simple, accurate, and fast procedure for quantitative analysis of fatty acids (FA) in simple lipid subclasses from different biological specimens is presented. Lipid extracts of isolated plasma lipoproteins (very low, low, and high density lipoproteins; VLDL, LDL, and HDL, respectively) and permanent J774 mouse macrophages were fractionated into lipid subclasses by thin-layer chromatography (TLC) on silica gel 60 plates. Bands comigrating with authentic lipid standards were scraped off under argon and subjected to direct,in situ transesterification with BF₃/MeOH in the presence of the TLC adsorbent. Fatty acid methyl esters were subsequently quantitated by capillary gas chromatography. A comparison of the FA content present in total lipid extracts and in lipid subclasses separated by TLC revealed recoveries ranging from 93 (J774 cell extracts) to 99.7% (LDL). The method described is applicable for the measurement of FA in individual lipid subclasses and was successfully applied to quantitatively analyze the FA composition of the phospholipid, triacylglycerol, and cholesteryl ester fraction derived from VLDL, LDL, and HDL. In J774 lipid extracts, the FA composition of the phospholipid-, monoacylglycerol-, diacylglycerol-, free fatty acid-, triacylglycerol-, and cholesteryl ester fraction was quantitated. In addition we have analyzed the time-dependent loss of the major HDL polyunsaturated fatty acids (18:2, 20:4) in the phospholipid and cholesteryl ester fraction during copper-dependent peroxidation of HDL. We have not encountered analytical problems concerning low FA recoveries from CE-rich lipid extracts as indicated by almost quantitative recoveries of FA in LDL, HDL, and J774 extracts.     

The circadian cycles of plasma corticosterone and adrenal cholesteryl esters in the normal and EFA-deficient female rat

In female rats subjected to a 12 hr light-12 hr darkness schedule and fed a semipurified diet containing 10% corn oil, plasma corticosterone concentration showed a monophasic circadian cycle with minimum and maximum concentrations at the start of the light and dark periods, respectively. Adrenal total cholesteryl ester concentration was inversely related to plasma corticosterone, as were those of several of the individual esters; changes in cholesteryl ester concentration appeared to follow rather than precede changes in plasma corticosterone. There was preferential depletion of the cholesteryl esters of 18∶1, 18∶2ω6, and 20∶4ω6 during glucocorticoid secretion. [Abbreviations: EFA, essential fatty acid (s);X:YωZ, fatty acid with X carbon atoms and Y olefinic bonds with the terminal double bond Z carbon atoms from the methyl group.] In female rats fed hydrogenated coconut oil (EFA-deficient), a monophasic cycle for plasma corticosterone was also observed, but the peak was much broader than that recorded for rats fed corn oil, although minima and maxima occurred at similar times for the two groups. No significant cycle of adrenal total cholesteryl esters was evident in the deficient rats, but the 20∶3ω9 and 22∶3ω9 esters did decrease significantly during the period of high plasma corticosterone concentration. Preferential net decreases in adrenal cholesteryl esters during corticosteroidogenesis were more apparent in normal than in EFA-deficient rats.     

Separation of neutral lipid,free fatty acid and phospholipid classes by normal phase HPLC

Normal phase high performance liquid chromatography methods are described for the separation of neutral lipid, fatty acid and five phospholipid classes using spectrophotometric detection at 206 nm. Separations were accomplished in less than 10 min for each lipid class. A mobile phase consisting of hexane/methyltertiarybutylether/acetic acid (100∶5∶0.02) proved effective in separating cholesteryl ester and triglyceride with recoveries of 100% for radiolabeled cholesteryl oleate and 98% for radiolabeled triolein. Free fatty acid and cholesterol were separated by two different mobile phases. The first, hexane/methyltertiarybutylether/acetic acid (70∶30∶0.02) effectively separated free fatty acids and cholesterol, but did not separate cholesterol from 1,2-diglyceride. A mobile phase consisting of hexane/isopropanol/acetic acid (100∶2∶0.02) effectively separated free fatty acid, cholesterol, 1,2-diglyceride and 1,3-diglyceride. Recoveries of oleic acid and cholesterol were 100% and 97%, respectively. Five phospholipid classes were separated using methylteriarybutylether/methanol/aqueous ammonium acetate (pH 8.6) (5∶8∶2) as the mobile phase. The recoveries of phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin and lysophosphatidylcholine were each greater than 96%.     

The effect of incubation temperature on yolk lipid parameters during embryonic development of the alligator (Alligator mississippiensis)

The effect of incubation temperature (30 and 33°C) on yolk lipid uptake and changes in the alligator has been studied. Notable changes occurred in the lipid and fatty acid compositions of the yolk. Triacylglycerols and phospholipids were the major lipid components of the yolk at the start of incubation. However, during incubation the level of cholesteryl esters increased considerably to become a major lipid component of the yolk at hatching. This increase in cholesteryl ester level occurred at a much earlier time in the eggs incubated at 33°C. The cholesteryl esters which accumulated within the yolk showed much higher levels of oleic acid. The triacylglycerols and phospholipids of the yolk both contained unusually high levels of palmitoleic acid. Their fatty acid compositions remained relatively unchanged during incubation. The lipid composition of the liver toward the end of the incubation period reflected the changes that occurred within the yolk. Thus the percentage of cholesteryl esters in the liver lipid of embryos incubated at 30 and 33°C were 7 and 40%, respectively. The accumulated cholesteryl esters also showed a significantly higher content of oleic acid. The differences in the yolk and tissue lipids during incubation at the two temperatures are discussed with reference to the respective rates of embryonic development but in particular with respect to the feature of temperature-dependent sex determination.     

Effect of dietary fat on rat liver microsomal and mitochondrial/lysosomal dolichol,phospholipid and cholesterol

The influence of different fat diets on liver phospholipid, cholesterol and dolichol was studied. Rats were separated into four groups and fed standard laboratory chow (control), a diet containing linolenic acid, a coconut oil diet, or a corn oil-containing diet. After five weeks, microsomes and mitochondrial/lysosomal fractions were prepared from the liver, and lipid compositions were analyzed. No changes in phospholipid content were observed. In control animals, the fatty acid compositions of phosphatidylcholine and phosphatidylethanolamine in the two subfractions were similar. However, these two phospholipids showed different fatty acid patterns, which were altered independently upon dietary treatment. The dietary treatments resulted, in most cases, in decreased cholesterol and dolichol contents and, especially in microsomes, in a decreased level of esterification of both lipids. The fatty acid compositions of cholesteryl esters in the two subfractions showed significant differences and cholesterol was esterified to a large extent with linolenic acid when this fatty acid was supplied in the diet. The same dietary treatment exerted different effects on the cholesterol localized in the two different intracellular compartments. This difference was most pronounced in rats fed the corn oil-containing diet; microsomal cholesteryl esters exhibited increased saturation, whereas cholesteryl esters in the mitochondrial/lysosomal fraction displayed decreased saturation. Dolichyl esters in the two cellular compartments had different fatty acyl compositions, with a considerably higher degree of saturation in microsomes. The various diets influenced the nature of the fatty acid moieties present in the isolated fractions and the effects on the two subfractions were opposite. The diet containing linolenic acid decreased the degree of saturation in microsomal dolichyl esters and increased the degree of saturation in the mitochondrial/lysosomal fraction. The results demonstrate that the fatty acid compositions of both dolichyl and cholesteryl esters display organelle specificity. Both the content of these lipids and their fatty acid compositions are greatly influenced by dietary conditions, and the esterification processes at different cellular locations exhibit independent regulation, regardless of the fatty acid content of the diet.     

Autoxidation of fatty acid monolayers adsorbed on silica gel: III. Effects of saturated fatty acids and cholesterol

Autoxidation of fatty acid monolayers on silica consisting of multiple components to simulate biomembranes has been studied by the rate of fatty acid disappearance and the products formed. When palmitic acid was incorporated into linoleic acid monolayers, the decrease in rate was proportional to the amounts of plamitic acid present. The protective effect of the saturated fatty acid diminished rapidly as the chain length of the saturated fatty acid decreased below C₁₂. With acids of medium chain length, C₁₂ was more effective than C₁₆. In pure linoleic acid monolayers, when the surface coverage was reduced to only 5% of the available adsorption sites, and in the case of palmitic acid-linoleic acid monolayers, the rate dropped drastically and the major identified product formed was hydroxyepoxyoctadecenoic acid. On the contrary, the major product formed in the case of saturated monolayers of pure linoleic acid was a mixture of unsubstituted epoxy acids. The inclusion of cholesterol in linoleic acid monolayers increased the rate of disappearance of linoleic acid slightly, whereas cholesteryl acetate decreased the rate. The protective effect exerted by cholesteryl acetate appeared to be similar to that of palmitic acid.     

尿素包合法分离棕榈油甲酯化产物中C_(16)和C_(18)脂肪酸甲酯

采用尿素包合法分离棕榈油甲酯化物中不同碳链长度的脂肪酸甲酯,为农产品涂膜保鲜材料的开发提供原料。重点考察了尿素用量、溶剂用量、包合时间和包合温度对分离效果的影响,并以尿素用量、95%乙醇用量、包合温度为三因素,C16脂肪酸甲酯和C18脂肪酸甲酯的纯度为二指标,根据Box-Benhnken中心组合试验设计原理,利用Designexpert7.0.1软件分析优化了分离的工艺条件并建立了回归模型。优化的最佳工艺条件如下:在棕榈油甲酯化物用量为20g,尿素用量为35g,95%乙醇用量为120mL,包合温度为5℃,包合时间为16h的条件下,饱和脂肪酸甲酯相中C16脂肪酸甲酯的含量达78.5%,不饱和脂肪酸甲酯相中C18脂肪酸甲酯的含量达93.1%,分别比原料提高36.4%和40.8%。