Supplemental dietary flaxseed oil affects both neutral and phospholipid fatty acids in cultured tilapia

This work aimed to evaluate the neutral lipid (NL) and phospholipid (PL) classes in tilapia (Oreochromis niloticus) muscle tissue. Tilapias were raised in captivity for a period of 5 months with increasing levels (0, 1.25, 2.50, 3.75, and 5.00%) of flaxseed oil [source of α‐linolenic acid (LNA), 18:3n‐3] in substitution for sunflower oil (control). The NL/PL ratio was 1.9, and 45 fatty acids were determined for both classes of lipid. The class totals of n‐3 acids always increased in all treatments, while the totals for n‐6 acids always decreased (p <0.05). For a given level of flaxseed oil, the LNA contents were consistently higher, including EPA (20:5n‐3) and DHA (22:6n‐3). Arachidonic acid (20:4n‐6) remained high in the PL but was reduced as levels of dietary flaxseed oil were increased. The n‐6/n‐3 ratios decreased significantly with the rise in flaxseed oil content in all treatments, and highly unsaturated fatty acid contents increased with the levels of flaxseed oil. Overall, the influence of flaxseed oil on the fatty acid composition in the contributing NL and PL classes was to increase n‐3 PUFA, thus raising the nutritional value of this freshwater fish meat and, consequently, contributing to the health of consumers.     

Viscosities of vegetable oils and fatty acids

Data for viscosity as a function of temperature from 24 to 110°C (75 to 230°F) have been measured for a number of vegetable oils (crambe, rapeseed, corn, soybean, milk-weed, coconut, lesquerella) and eight fatty acids in the range from C₉ to C₂₂. The viscosity measurements were performed according to ASTM test methods D 445 and D 446. Several correlations were fitted to the experimental data. Correlation constants for the best fit are presented. The range of temperature in which the correlations are valid is from 24°C (75°F), or the melting point of the substance, to 110°C (230°F). The correlation constants are valuable for designing or evaluating such chemical process equipment as heat exchangers, reactors, distillation columns, mixing vessels and process piping.     

Surface tension of fatty acids and triglycerides

Surface tension as a function of temperature was measured for four fatty acids (lauric, myristic, palmitic, and oleic) and two triglycerides (tricaprylin and tripalmitin). These surface tension measurements were performed using a K12 vers. 3.1 (Krüss GmbH) tensiometer at temperatures from 20 (or the melting point of each substance) to 90°C. The constants for a van der Waals-type correlation as well as for a linear equation are presented. Both equations are quite accurate, presenting mean deviations not exceeding 0.570%. Such correlation constants are valuable in the design or evaluation of processing equipment, especially that involving gas-liquid contact such as distillation and stripping columns, deodorizers, reactors, and equipment for physical refining.     

Solubility of fatty acids in subcritical water

A phase equilibrium apparatus was designed to determine the solubilities of stearic acid and palmitic acid in subcritical water at different temperatures and pressures. The dissolution equilibrium time was measured. The effect of an ultrasonic field on dissolution equilibrium was also studied. The results showed that the maximum solubilities of stearic acid and palmitic acid were 0.136 g/100 g and 0.178 g/100 g in subcritical water at temperatures of 180 °C and 160 °C, respectively, and a pressure of 15 MPa for 30 min. An ultrasonic field also clearly promoted the dissolution of fatty acids in subcritical water. The dissolution equilibrium time was shortened to 20 min using ultrasonic oscillation (250 W, 20 kHz).     

Solubility of fatty acids in supercritical carbon dioxide

The solubilities of lauric, linoleic, myristic, oleic, palmitic and stearic acid in supercritical carbon dioxide (SC-CO₂) at different pressures and temperatures were measured. The solubility values obtained in this work were compared with previously published data, and possible causes for observed discrepancies were discussed. The solubilities of the six fatty acids were modeled by Chrastil’s equation, and estimated model parameters were used to plot the solubility isotherms of fatty acids at 313, 323 and 333°K (40, 50 and 60°C) as a function of SC-CO₂ density. The comparison of solubility isotherms of fatty acids and vegetable oil suggests that separation of fatty acids from triglycerides might be possible by using SC-CO₂ at densities less than 700 kg/m³. From the effect of temperature on fatty-acid and vegetable-oil solubility, it seems that the extraction yield could be increased without sacrificing the selectivity of SC-CO₂ for fatty acids by choosing a higher operating temperature. The data also suggest that fractionation of certain fatty acids might be possible by manipulating the processing conditions. Given the values of the constants, Chrastil’s equation could serve as a guideline for choosing appropriate processing conditions and predicting the effect of pressure and temperature of SC-CO₂ on solute solubility.     

Genetic diversity of fatty acids in sesame and its relatives in Nigeria

The genetic diversity in seed lipid and fatty acid composition in nine accessions of sesame, comprising six cultivated and three wild relatives, was studied and compared. Seed oil content was 53.23–55.12% in cultivated and 53.35–58.56% in wild accessions. The principal fatty acids in the accessions were palmitic, stearic, oleic (OLE), linoleic (LIN) and linolenic (LIL) acids, of which lower OLE and higher LIN acids were observed in all the accessions. Principal component analysis revealed that OLE acid, total unsaturated fatty acids, total saturated fatty acids (SFAs), LIN acid and the unsaturated to SFA ratio had the highest loading in the first component, which accounted for 54.01% of the total variation. For the second principal components, lauric, palmitoleic, capric, lignoceric, arachidic and LIL acids had the highest loading, accounting for 26.94% of the total variation. Three principal components explained 89.01% of the total variation. The dendrogram generated by the UPGMA cluster analysis grouped the nine accessions into five distinct clusters, indicating genetic diversity; this can be used to plan crosses and maximise the expression of heterosis. Practical applications : This research work provides information on the fatty acid profile of seed oil from nine morphologically distinct accessions of sesame selected from thirty‐three accessions collected in 2003. This is intended to establish genetic diversity on the basis of fatty acid profile, identify accessions with high seed oil quality that may be adopted for large scale cultivation in Nigeria and justify the suitability of the nine accessions in serving as base materials in the ongoing breeding efforts for sesame seed oil quantity and quality improvement.     

Polyoxyethylene esters of fatty acids: an alternative synthetic route for high selectivity of monoesters

Esterification reaction of fatty acids with polyoxyethylenes has been studied in the presence of solid acid catalysts and the results are compared with those obtained with a classical homogeneous catalyst, p-toluene sulphonic acid. Solid acid catalysts showed very high selectivities for monoesters even under less favorable reaction conditions of 1:1 molar ratios of oleic acid to PEG. Excess amount of PEG is normally required to ensure high selectivity for monoesters in the presence of homogeneous catalysts. The yields for monoesters given by heterogeneous catalysts such as zeolites, HPA and nafion were comparable to that with p-toluene sulphonic acid after 24 h of reaction. Results suggest that solid acid catalysts are potential catalysts for selective synthesis of monoesters from oleic acids and PEG even under severe reaction conditions. A screening study of different solid acid catalysts showed ZSM-5, zeolite-β, and nafion to be better catalysts than zeolite USY and mordenite, the former giving higher selectivity and yield to monoesters. The results suggest that the most important parameters in optimization catalyst performance for monoesters production is the acid strength and less so on other properties such as shape selectivity and concentration of active sites.     

The effects of season on fat and fatty acids contents of shrimp and prawn species

The effects of seasons on the lipid content and fatty acid compositions of five different shrimp and prawn species (green tiger prawn – Penaeus semisulcatus, kuruma prawn – Marsupenaeus japonicus, caramote prawn – Melicertus kerathurus, deepwater pink shrimp – Parapenaeus longirostris, speckled shrimp – Metapenaeus monoceros) were evaluated. Results showed that lipid content ranged from 0.89 to 1.55% in muscle, showing that all species were considered as lean. There were significant differences (p<0.05) in the levels of saturated fatty acids (SFA), monounsaturated fatty acids and polyunsaturated fatty acids (PUFA) in terms of season and species. They were rich in n‐3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The highest proportions of EPA were obtained from kuruma prawn (180.9 mg/100 g) in spring and deepwater pink shrimp (173.2 mg/100 g) and caramote prawn (146.3 mg/100 g) in summer. Kuruma prawn had the highest DHA in spring (140.8 mg/100 g) followed by deepwater pink shrimp (132.2 mg/100 g) and caramote prawn (129.6 mg/100 g) in summer. The results also showed that the seasons affected lipid content and the fatty acid composition of shrimp and prawn species. Practical Application: The beneficial effect of seafood consumption on human health has been related to the high content of n‐3 fatty acids, especially EPA (20:5n‐3) and DHA (22:6n‐3). The ratios of n‐6/n‐3, PUFA/SFA and EPA + DHA are considered as useful criteria for comparing relative nutritional and oxidation values of marine oils. In the current study, the influence of seasonality on the lipid content and the fatty acid compositions of shrimp and prawn were investigated in order to find the best source of n‐3 fatty acids during the year.     

Dietary fatty acids influence the growth and fatty acid composition of the yellow mealworm <Emphasis Type="Italic">Tenebrio molitor</Emphasis> (Coleoptera: Tenebrionidae)

Fat is the second most abundant component of the nutrient composition of the mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) that represents also an interesting source of PUFA, especially n-6 and n-3 fatty acids, involved in prevention of cardiovascular diseases. This study investigated the possibility of modifying the fat content and the FA composition of yellow mealworms through feeding and how this would be influenced by developmental stages, pupal sex, and generation with the future aim of applying this coleopteran as a diet supplement for human health. Growth rate and cumulative mortality percentage on the different feeding substrates were also evaluated to select the optimal conditions for a mass-raising of this insect species. Despite the different fat content in the six different breeding substrates used, T. molitor larvae and pupae contained a constant fat percentage (>34% in larvae and >30% in pupae). A similar total fat content was found comparing larvae and male and female pupae of the second generation to those of the first generation. On the contrary, FA composition differed both in larvae and pupae reared on the different feeding substrates. However, the exemplars reared on the diets based on 100% bread and 100% oat flour showed SFA, PUFA percentages, and an n-6/n-3 ratio more suitable for human consumption; the diet based on beer yeast, wheat flour, and oat flour resulted in a contemporary diet that most satisfied the balance between a fat composition of high quality and favorable growth conditions.     

Entrainer selection for the synthesis of fatty acid esters by Entrainer-based Reactive Distillation

In this research it is demonstrated that, due to the similarities between Entrainer-based Reactive Distillation and azeotropic distillation, the same selection rules can be applied to select a suitable entrainer. From a list of suitable entrainers for the azeotropic distillation of isopropanol and water, cyclohexane and isopropyl acetate are chosen. Residue curve maps, simulations of the distillation section of the column, and simulations of the total Entrainer-based Reactive Distillation concept show that both can be used as an entrainer in Entrainer-based Reactive Distillation. Whether the Entrainer-based Reactive Distillation concept will be feasible, depends strongly on the kinetics of the reaction.     

Methylation of wood fatty and resin acids for production of biodiesel

The purpose of the present paper is to evaluate the potentiality of the wood oil of Oriental spruce (Spruce orientalis) for biodiesel production. Two methods have been applied for obtained wood oil with and without solvent such as separation of crude tall oil from sulfate soaps by Kraft pulping process. Production of biodiesel from wood oil follows two steps, first extraction of oil using a solvent (acetone) and then base catalyzed (KOH) or non-catalytic supercritical methanol transesterification. This paper studied the effect of temperature on transesterification of wood oil to find the optimum temperature of maximum biodiesel yield. Transesterification of the wood oils were performed in a 100-mL cylindrical autoclave using supercritical methanol. In a typical run, the autoclave was charged with a given amount of the wood oil (20-25 g) and alcohol (20-50 g) with changed molar ratios at 500, 525, 550 and 575 K. The yield of the biodiesel produced under optimal condition is 96-98%.     

乌桕脂脂肪酸提取和分离的研究

由油脂精细化工的理论和实践,提出乌桕脂脂肪酸提取和分离的清洁工艺,并与现有工艺比较,说明该工艺的优越性     

An improved micro-extraction cell for supercritical fluid extraction and chromatography of fatty acids

An improved supercritical fluid micro-extraction cell of increased reliability was designed for on-line supercritical fluid extraction and chromatography (SFE/SFC) of food and other lipid-related samples. The key components in the modified cell include a Swagelok stainless steel reducing union with a dual ferrule as the cell, with polyetherether-ketone (PEEK) ferrules and nuts to connect the cell to the control valve. The new cell did not leak under all conditions examined (100–500 atmospheres, 40–80°C), even after numerous extractions (>250). The quantitative performance of the cell was evaluated with fatty acid standard solutions, technical grade fatty acid sources and wheat flour. The percent relative error (%RE) for the fatty acid standards and technical-grade fatty acid samples was ≤6.0% for oleic, linoleic and linolenic acid. The %RE for oleic and linoleic acid in the whole-wheat samples was ≤10%. The results demonstrate that the new extraction cell can be used for quantitative extractions and that the sensitivity of the SFE/SFC technique is excellent. Similar SFE/SFC methods could prove useful in studying the interaction of free fatty acids with various food components such as enzymes, amylose and proteins.     

微 波快速合成芳氧乙酸

在无溶剂体系中，使用微波辐射快速合成了３种芳氧乙酸。该方法反应条件温和、反应时间短、收率高，操作简便。反应２．５－３ｍｉｎ收率可达８６．８％－９４．１％。     

Direct esterification of fatty acids with phenylalkanols by using dicyclohexylcarbodiimide

A mild one‐pot esterification method of fatty acids with alcohols at room temperature is described. The reaction of undec‐10‐enoic acid (I) with 1‐phenylethanol in the presence of N,N'‐di‐cyclohexylcarbodiimide and 4‐(N,N‐dimethylamino)pyridine gave 1'‐phenylethyl undec‐10‐enoate in quantitative yield. Similar reactions were also carried out with (Z)‐octadec‐9‐enoic acid, (Z)‐12‐hydroxyoctadec‐9‐enoic and (Z)‐9‐hydroxyoctadec‐12‐enoic acids. In addition, compound (I) was allowed to react with diphenyl methanol to form its corresponding ester. The structure elucidation of the prepared esters is based on the elemental analysis and spectral data (IR, ¹H‐ and ¹³C‐NMR, MS).     

Viscosities of some long-chain fatty acids and their relationship with chainlength

The densities and viscosities of octanoic, decanoic, dodecanoic and tetradecanoic acids were determined at temperatures ranging from 20 to 80°C. When the fluidities were plotted against the molal volumes of the acids, curves were obtained. The intrinsic volumes were determined by extrapolation to zero fluidity and compared with previously reported values. Based upon Hildebrand’s equation for non- associated liquids, semiempirical equations relating the fluidity with the carbon number were obtained. The equations predict the fluidities of fatty acids with carbon number ranging from 4 to 18 at 4 temperatures from 20°C to 75°C with reasonable agreement with the experimental values.