Fatty acid and phytosterol accumulation during seed development in three oilseed species

This study was carried out to compare the kinetic accumulation of bioactive lipids during seed development in three oil crops rapeseed, sunflower and woad. Field experiments were conducted under organic conditions during 3 years. After flowering, seeds were collected each 4–5 days until harvest. The three species differed by the quantity and quality of both fatty acids and sterols. Higher levels of phytosterols and fatty acids were reached between 20 and 40 days after flowering (DAF) in sunflower, 40 and 60 DAF in rapeseed and 25 and 45 DAF for woad. The modification of lipid composition during the grain filling depends on species. Knowledge of the composition and accumulation of fatty acids and phytosterols in sunflower, rapeseed and woad seeds would assist in efforts to achieve industrial applications. These seeds may give an interesting source of bioactive lipids.     

Convenient thionation of triglycerides with lawessons reagent

Thionation using the Lawesson’s reagent (LR) led to quantitative and selective replacement of carbonyl groups (C=O) with thionocarbonyl groups (C=S). Mixtures of thionotriglycerides were obtained by reaction of 2,4-bis (p-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide in suspension with triglycerides (TG). With a molar ratio (LR)/(TG)=3∶2, there was complete exchange of C=O with C=S in the carboxylic groups of the TG. The yield is over 90%. The two P=S ligands in the LR confer a double reactivity, producing a high power of thionation. Fourier transform infrared spectroscopy was employed for quantitative and qualitative characterization of the thionated TG and for monitoring the progress of partial or total thionation as conditioned by the molar ratios of the starting compounds. Thus, with molar ration LR/TG of 0.108, 0.36, and 0.72, we obtained around 6, 20, and 40% of C=O conversion, respectively.     

Quantification of Mixtures of C2 and C3 Hydroxy Acids and Products of Glycerol Oxidation by High-Performance Liquid Chromatography and Quantitative 13C NMR

The aim of this study was to develop an improved general method for detecting and quantifying mixtures of hydroxy acids and other products of glycerol oxidation in aqueous media, to prevent the confusions that can occur due to similarities and interactions between these compounds depending on media conditions. Standard potential products of glycerol oxidation—glycerol, glyceraldehyde, dihydroxyacetone, glyceric acid, lactic acid, glycolic acid, glyoxylic acid, oxalic acid, tartronic acid, and mesoxalic acid—were analyzed by high-performance liquid chromatography (HPLC) and quantitative ¹³C nuclear magnetic resonance (NMR), in mixtures of known composition. The results obtained were concordant with the known compositions tested. HPLC was more accurate than quantitative ¹³C NMR for simple mixtures, but ¹³C NMR was required for complex mixtures containing dihydroxyacetone and glycerol, oxalic acid and mesoxalic acid, or glyoxylic acid and tartronic acid, pairs of compounds not well separated or detected by HPLC. As proof-of-concept, an unknown mixture generated by glycerol oxidation was analyzed by HPLC and quantitative ¹³C NMR. The results obtained were concordant and allowed accurate determination of the composition of the sample, which contained mesoxalic acid as the major product, with oxalic acid, tartronic acid, and glyceric acid as by-products.     

Structural Analysis of Partial and Total Esters of Glycerol Undecenoate and Diglycerol Undecenoate

The direct esterification reaction between glycerol and undecylenic acid or between diglycerol and undecylenic acid generates all the possible types of glycerol or diglycerol esters. Purification by silica gel chromatography resulted in the isolation of each of these types of ester in a pure form. The molecular structures of the compounds isolated were characterized and identified by mass spectrometry, ¹H NMR, ¹³C NMR and DEPT‐135. We then studied the composition of esters of undecylenic acid formed with glycerol or diglycerol as a function of their reaction conditions, which constitute a highly complex system. We purified undecylenic acid esters from each polyol family to allow the structural identification of each ester of glycerol and each ester of diglycerol with undecylenic acid. We found that the polarity of these non‐ionic amphiphilic esters directly affected their affinity for organic and inorganic solvents and that these esters behaved very differently from anionic amphiphilic molecules, such as undecylenic acid.     

Effects of genotype and sowing date on phytostanol–phytosterol content and agronomic traits in wheat under organic agriculture

Cereals are an important source of sterols and stanols in the human diet. The present study underlines the effect of genotype and weather conditions in bread wheat, on total sterol and stanol content (TSS), agronomic traits, proteins and ash content under organic conditions. Variations in TSS as well as other characters between two sowing dates were observed. A broad genotypic variability was also reported since extreme genotypes differed by more than 30 mg 100 g⁻¹ DW for TSS, with total stanol content varying twofold. Moreover, two groups of genotypes that differed in agronomic production, ash and protein content were depicted, based on their response to an increase in temperature. This result suggests that the genotypic factor prevails over the sowing date factor for determining sterol and stanol traits in wheat cultivated under organic conditions. Nevertheless, a strong interaction exists between the two factors, which can be used to drive bioaccumulation of these molecules.     

Separation and quantitation of mono-, di-, and triglycerides and free oleic acid using thin-layer chromatography with flame-ionization detection

α-Monoolein was prepared from glycidol and oleic acid by the regioselective opening of glycidol in the presence of an anionic resin. During the reaction, the lipochemical synthesis medium becomes enriched in monoolein, the effective emulsifying agent. This mixture can be analyzed by thinlayer chromatography coupled with flame-ionization detection (FID). The products and reagents do not need to be derivatized. Diglyceride and triglyceride by-products affecting the selectivity of the reaction also could be detected using this technique. Cholesterol was used as an internal standard. The factors influencing the separation, including the hydrogen flow rate, scan speed, and the composition of the developing solvent, were investigated. The degree of separation is highly sensitive to the hexane/diethyl ether ratio of the developing solvent. Good separation of triglyceride, oleic acid, the two diglycerides, cholesterol, α-monoolein, and glycidol was obtained with the mixture hexane/diethyl ether/formic acid (65:35:0.04, by vol). Detector response, detection limits, and rod-to-rod variations also were examined. A range of rod loads giving a straightforward relationship between FID response and amount of compound loaded (relative to oleic acid and α-monoolein) was defined. The accuracy of the quantification was illustrated by analysis of a mixture of oleic acid and α-monoolein standards of known composition. Presented at the AOCS conference, New Trends in Lipid and Lippprotein Analysis, La Grande Motte, France, September 1993.     

Synthesis of alkyloxy (di)alkylamino propanols, hydroxy alkyloxy (di)alkylamino propanols, and the dimer compounds for use as fuel additives

Alkyl glycidyl ethers and bis glycidyl ethers, synthesized in a heterogeneous weakly hydrous medium, were condensed with primary or secondary amines to obtain 3-alkyloxy propanolamines or bis alkyloxy propanolamines in a regioselective manner. The compounds were characterized by conventional spectroscopic methods, and complete nuclear magnetic resonance data are given. Their high-temperature stability, their good emulsifying power, their oxidation, and corrosion inhibition make these compounds suitable for solubilizing ethanol-diesel fuel blends.     

Synthesis of glycerol carbonate by direct carbonatation of glycerol in supercritical CO2 in the presence of zeolites and ion exchange resins

Glycerol carbonate is a key bifunctional compound employed as solvent, additive, monomer, and chemical intermediate. We have synthesized it on a pilot scale in the laboratory in cyclic or alicyclic organic carbonate medium. In this study, we examined the use of supercritical CO₂ as a reaction medium and as a source of carbonate for carbonatation of glycerol. Glycerol carbonate could be obtained by direct reaction of carbon dioxide with an organic carbonate in the presence of heterogeneous catalysts. Carbonatation of glycerol into glycerol carbonate went to equilibrium in supercritical CO₂ medium. This revised version was published online in July 2006 with corrections to the Cover Date.     

High concentration of 1-(3-)monoglycerides by direct partial esterification of fatty acids with glycerol

An improved method for the production of monoglycerides (MO) by direct esterification of fatty acids with glycerol was developed. The reaction medium was composed of oleic acid (72% purity, OA), glycerol (Gly), dodecylbenzene sulfonic acid (DBSA) as catalyst, and emulsifying agent, as well as of a molecular sieve as drying agent. Partial esterification of glycerol by oleic acid is carried out in either a batch reactor and in a column filled with a molecular sieve according to a continuous process. In a discontinuous batch reactor, the OA/Gly/DBSA system gives 28% of 1-(3-)MO and strong proportions of di- and triesters. The addition of the 3A molecular sieve to this system makes it possible to increase the selectivity in 1-(3-)MO (47%). However, the reaction carried out in a column filled with a 3A molecular sieve produced a mixture containing 60% of 1-(3-)MO after deacidification and removal of the catalyst and shows the advantage of a continuous process.     

O-etherification between glycerol and glycerol monooleate—demonstration of formation of diglycerol monooleate and triglycerol monooleate by fast atom bombardment-mass spectroscopy and 13C nuclear magnetic resonance

To prepare glycerol monooleate, we reacted glycerol with oleic acid in the presence of a K1411 sulfonic acid resin in the H⁺ form. We utilized glycerol monooleate as an emulsifying agent, as it is a nonionic surfactant that is compatible with the initially biphasic reaction medium. If the expected product does not form, small amounts of a highly polar compound are produced. Both diglycerol monooleate and triglycerol monooleate were isolated by preparative chromatography on a silica column (hexane/chloroform/acetone, 25∶50∶50), and were formally identified by fast atom bombardment (FAB)-mass spectroscopy in positive mode. The products were polyglycerol monoesters. The nature of the products was confirmed by the use of different FAB matrices with or without cationization by alkali metals. The structure of the product was then confirmed by ¹³C nuclear magnetic resonance. we can now propose a new method of polyglycerol ester preparation that yields interesting nonionic emulsifying agents.