Optimal conditions for fractionation of rapeseed lecithin with alcohols

Deoiled rapeseed lecithin was fractionated with ethanol, and optimum conditions have been determined to improve purified lecithin yield and phosphatidylcholine (PC) enrichment. The effect of extraction time, solvent volume, ethanol concentration and temperature on the yield and the PC enrichment have been described in the form of regression equations. A full factorial experiment method and a second-order orthogonal design were used in the study. The regression equations were calculated for the maximum value of the response functions optimized by an electronic data processing method, and the results (yield and PC enrichment calculated from regression equations) were compared with those obtained in control experiments. The use of calculated optimal parameters in the fractionation process led to 81–96% and 58% increments in yield and PC enrichment, respectively.     

Development of Industrially Scalable Method for Phospholipids and Branch-Chain Fatty Acids of Dairy by-Product

Dairy phospholipids (PL) is of interest due to their health benefits and functional properties. Solvent fractionation of PL has not been commonly used in the dairy industry to fractionate milk fat to obtain or concentrate the PL. The total lipid extracted from the β stream, a waste by-product of dairy processing, was used in this study to investigate suitable solvent and conditions to separate the neutral lipid from PL. A fixed lipid solvent ratio (1:10 g/v) was used at various fractionation temperatures (−20, 2, 15, 23, 40, and 60 °C) depending on the solvents. The use of acetone at 23 °C, not at the lower temperatures, led to a dairy lecithin product with high PL content, such as 71.5%. The more aqueous ethanol, i.e. at 70% concentration compared to 95%, was able to preferentially extract PL to form products with up to 74.7% PL, but the PL yield was much lower (26.3%) compared to acetone precipitation (97.9%). The enrichment of branch chain fatty acids proved to be very challenging due to the overlapping melting points with other fatty acids. The composition of the major fatty acids of polar and neutral lipids also showed interesting patterns that may indicate different nutritional and oxidative properties of the fractionated products.     

Soybean lecithin fractionation and functionality

Soybean lecithin contains primarity PC, PE, and PI. Fractionation of these phospholipids (PL) is desirable for certain applications. Ethanol was used to fractionate PC and PI, which have different solubilities in this solvent. Various concentrations of ethanol (90, 95, and 100%) and ethanol/gum ratios (0.5, 1.0, 1.5, 2.0, and 2.5) were used. Ethanol concentration significantly influenced the yield of the PC-enriched fraction and the PC and PI fractionation: The highest ethanol concentration resulted in the highest yield of PC fraction, the most PC in the PC fraction, and the most PI in the PI fraction. The ethanol/gum ratio significantly affected the yield of PC-enriched fraction, but did not affect the relative PL composition of the PC-enriched fraction. Ethanol of 90% concentration with a solvent/gum ratio of 3 was used for further large-scale fractionation. Such fractionation resulted in a PC-enriched fraction containing 73% PC, 24% PE, and 3% PI based on the total PL content, whereas the PI fraction contained 26% PC, 35% PE, and 39% PI. Functional properties of these two purified fractions, i.e., surface tension reduction, emulsion stability, and oxidative stability, were investigated. The PI-enriched fraction had a much lower critical micelle concentration than the PC-enriched fraction, which suggests the PI-enriched fraction has a higher surface tension reduction capability. For the emulsion stability test, the PI-enriched fraction performed better than the PC fraction in both water-in-oil and oil-in-water emulsions. An oxidative stability test showed that these PL were very stable to lipid oxidation.     

Sunflower Lecithin: Application of a Fractionation Process with Absolute Ethanol

Native or modified lecithins are widely used as a multifunctional ingredient in the food industry. A fractionation process of sunflower lecithin (a non GMO product) with absolute ethanol was used for obtaining enriched fractions in certain phospholipids under different experimental conditions (temperature 35–65 °C, time of fractionation 30–90 min, ethanol/lecithin ratio 2:1, 3:1). Phospholipid enrichment in PC and PI fractions was obtained and analyzed by ³¹P NMR determinations. The percent extraction coefficients for different phospholipids (%E_PC, %E_PE and %E_PI) in both fractions were calculated. Values of %E_PC in PC fractions significantly increased (p < 0.05) from 12.8 (35 °C, 30 min, 2:1) to 57.7 (65 °C, 90 min, 3:1) at increasing temperature and incubation time. %E_PE varied from 3.0 to 18.3 in the same fraction while %E_PI presented lower values (<3%) under all the conditions assayed. The study of the effect of the operating conditions on the fractionation process evidenced a relevant influence of temperature, incubation time and to a minor extent of the ethanol/lecithin ratio on the enriched fraction yield% and selectivity of the main phospholipids (PC, PI, PE) estimated by %E_PL. Response surface methodology (RSM) was utilized to explain the influence of the different parameters to optimize this process.     

Selective extraction of phosphatidylcholine from lecithin by supercritical carbon dioxide/ethanol mixture

Selective extraction of phosphatidylcholine (PC) from deoiled soybean lecithin using supercritical fluid (SCF) mixtures of carbon dioxide (CO₂) and ethanol was studied at moderate pressures. Temperature was varied between 60 and 80°C at pressures of 17.2 and 20.7 MPa. Ethanol was added as co-solvent to supercritical CO₂ at the levels of 10 and 12.5 wt%. Constant rate of extraction of the individual phospholipids (PL) was observed for 150 min during which the extractions were carried out. Pressure and ethanol fraction had a positive effect on the selective extraction of PC, whereas temperature had a negative effect. Under all the conditions studied, the extracts were mainly composed of PC while the extraction of the other PL was very low. Extraction at 60°C and 20.7 MPa with 10 wt% ethanol/90 wt% CO₂ SCF mixture resulted in 95% selectivity to PC.     

Enzymatic synthesis of monoglycerides in a membrane bioreactor with an in-line adsorption column

The chemical synthesis of monoglycerides requires high temperatures, which may lead to the polymerization of unsaturated fatty acids. The enzymatic synthesis of these esters is performed at moderate temperatures and, hence, polymerization is avoided. However, enzymatic processes often end up with a mixture of the product, by-product, substrate and enzyme. An alternative process is an immobilized enzyme membrane reactor equipped with an inline adsorption column to adsorb the monoglycerides, preferentially onto the adsorbate. A silica 60 column has shown preferential adsorption of monocaprinate. The adsorption of a mixture of decanoic acid, mono- and diglycerides is based on two different mechanisms. The decanoic acid will interact with hydroxyl groups at the silica gel surface, which results in a noncompetitive decanoic acid adsorption onto 25% of the silica gel surface. On the remaining part of the silica gel surface, mono- and diglycerides adsorb competitively. When a mild eluant is used, such as 5% ethanol in hexane, only the competitively adsorbed molecules are desorbed. This results in a purification factor of approximately 90% after desorption. The column can be desorbed off-line in a continuous membrane/repeated batch column process. This results in an estimated production of monoglycerides of 60 mol (15 kg) of monoester per gram enzyme.     

Fractionation of crude soybean lecithin with aqueous ethanol

Aqueous ethanol was used to fractionate soybean PC and PI, which have dissimilar solubilities in this solvent. The effects of oil and moisture contents of the crude lecithin, ethanol-to-lecithin ratio, and dispersion temperature on the efficiency of phospholipid (PL) fractionation were investigated. Yield, purity, recovery, and PL class composition were examined. Yield was defined as the amount of fractionated material, divided by the acetone-insoluble (AI) matter in the starting material; purity was the percentage of PL (PC+PE+PI) as quantified by HPLC in the fraction; and recovery was the amount of PL quantified relative to the quantity of AI matter. Higher oil contents significantly increased the yield of the PC fraction, but they significantly decreased yield, purity, and recovery of the PI fraction. They also significantly affected the PL composition of the PC fraction. Higher moisture contents significantly decreased the yield but slightly increased the purity of PC fractions. Higher temperatures significantly increased the yield and recovery of the PC fraction. They also affected the relative proportion of PL classes in the PC and PI fractions. The ethanol-to-lecithin ratio significantly affected yield, purity, and recovery as well as the relative proportions of PL in both PC and PI fractions. A combination of multiple fractionation and high-low temperature treatment was also examined. Fractionating twice with ethanol increased the purity of the PC fraction. High-low temperature fractionation increased the purity and PC percentage in the PC fraction.     

Studies on stability of rapeseed wet gum as a source of pharmaceutical lecithin

Lecithin wet gum with high water content is less stable during storage than dry lecithin. Deoiling and dehydrating the fresh gum can result in a purified lecithin of high quality. The stability of rapeseed wet gum obtained from double-zero rapeseed varieties was determined at various temperatures. The effect of storage time on volatile substances, acetone insolubles, neutral lipids and acid, iodine, and peroxide values were investigated. The rapeseed wet gum stored a little above 20°C is stable for up to ten days, although in the frozen state (−20°C) no changes in general composition, acid, iodine, and peroxide values were observed during 24 mon of storage.     

Recovery of sterols as fatty acid steryl esters from waste material after purification of tocopherols

Tocopherols are purified industrially from soybean oil deodorizer distillate by a process comprising distillation and ethanol fractionation. The waste material after ethanol fractionation (TC waste) contains 75% sterols, but a purification process has not yet been developed. We thus attempted to purify sterols by a process including a lipase-catalyzed reaction. Candida rugosa lipase efficiently esterified sterols in TC waste with oleic acid (OA). After studying several factors affecting esterification, the reaction conditions were determined as follows: ratio of TC waste/OA, 1∶2 (wt/wt); water content, 30%; amount of lipase, 120 U/g-reaction mixture; temperature, 40°C. Under these conditions, the degree of esterification reached 82.7% after 24 h. FA steryl esters (steryl esters) in the oil layer were purified successfully by short-path distillation (purity, 94.9%; recovery, 73.1%). When sterols in TC waste were esterified with FFA originating from olive, soybean, rapeseed, safflower, sunflower, and linseed oils, the FA compositions of the steryl esters differed somewhat from those of the original oils: The content of saturated FA was lower and that of unsaturated FA was higher. The m.p. of the steryl esters synthesized (21.7–36.5°C) were remarkably low compared with those of the steryl esters purified from high-b.p. soybean oil deodorizer distillate substances (56.5°C; JAOCS 80, 341–346, 2003). The low-m.p. steryl esters were soluble in rapeseed oil even at a final concentration of 10%.     

Fraktionierung von Sojalecithin mit Alkoholen

Fractionation of Soy Lecithin with Alcohols Commercial soy lecithin contains about 55% phosphatides, which consist of about 30% phosphatidyl choline (PC), 20% phosphatidyl ethanolamine (PE) and phosphatidyl inosite (PI) and phytoglykolipids (each 15%). For many scopes or application lecithin preparations with a higher PC-content are desired, which can be obtained as known for long by fractionation of raw lecithin by alcohols. It was tested in systematic trials which solvent or solvent mixture the highest selectivity has and which yield the different extraction processes have. Products with highest PC/PE quotient were obtained by use of a) anhydrous methanol, b) water containing methanol or ethanol with 5 to 20% water and c) the ternary mixture methanol-isopropanol-water (55 + 40 + 5% v/v). The extraction yield of the one-step process was between 30 and 40%. It could be increased up to about 80% by simultaneous use of non polar solvents, e.g. hexane, or by use of counter current technic.     

Adsorption and Thermal Desorption of Volatile Organic Compounds in a Fixed Bed – Experimental and Modeling

Adsorption and thermal desorption dynamics of acetone in fixed-bed silica gel were studied experimentally and theoretically. The effect of process factors on adsorption and desorption performances was established. Acetone adsorption from air stream was performed by the dynamic (flowing gas) method in a laboratory setup at two levels of air superficial velocity (0.7 and 1.7 cm s^?1), temperature (30 and 40°C), and adsorbent particle diameter (0.21 and 0.54 cm). The values of saturation adsorption capacity (0.147–0.270 g g^?1) increased up to 78% and 36%, respectively, with a decrease in air velocity and adsorption temperature. Acetone thermal desorption from spent silica gel was studied in a thermobalance at three levels of process temperature (60, 70, and 80°C) and two values of particle size (0.21 and 0.54 cm). Equilibrium desorption efficiency (63–81%) was up to 14% larger for finer particles and increased with the desorption temperature. Kinetic models with relevant parameters adjusted based on experimental data were adopted to predict the dynamics of acetone adsorption and thermal desorption. The models simulated well the real conditions and could be applied to scale up and operate the adsorption columns used for air remediation.     

Dairy Lecithin from Cheese Whey Fat Globule Membrane: Its Extraction, Composition, Oxidative Stability, and Emulsifying Properties

An ethanol extraction method was studied for the production of dairy lecithin from cheese whey-derived milk fat globule membrane (MFGM). A two-step ethanol extraction of MFGM involving first extraction at pH 6.5, followed by second extraction at pH 4.5 yielded 17.2 % lipids. The extracted material contained about 90 % lipids, 4.5 % ash, and 1.2 % moisture. The phospholipid content of the ethanol extract was 31 % and the remainder was mostly neutral lipids. The phospholipid fraction contained 34 % sphingomyelin, 31 % phosphatidylcholine, 27 % phosphatidylethanolamine, 4.6 % phosphatidylserine, and 3.1 % phosphatidylinositol. Since the ethanol extract contained 31 % phospholipids, it can be technically termed as dairy lecithin. The major fatty acid components were linoleic acid (5.1 %), myristic acid (8.3 %), palmitic acid (29 %), stearic acid (14 %), oleic acid (25 %), and the remainder was minor fatty acids with chain length ranging from C4:0 to C22:5. The dairy lecithin was semi-solid at room temperature and exhibited a major phase transition at about 35 °C. Owing to its low polyunsaturated fatty acid content, the dairy lecithin was reasonably stable to oxidation as measured by the rate and extent of hexanal production during 35 days of storage at 45 °C. Oil-in-water emulsions made with less than 2 % dairy lecithin (relative to the total emulsion weight) were unstable; however, emulsions made with greater than 4 % dairy lecithin were very stable for more than 60 days at room temperature. The results of this study indicated that a highly functional dairy lecithin can be commercially produced using cheese whey-derived MFGM as the starting material.     

HPLC and Phospholipids Part II: Determination of PC and LPC in Defatted Soyabean Lecithins

The possibility of using HPLC for the analysis of the phosphatidylcholine content of high grade defatted soyabean lecithins of pharmaceutical interest was studied. Using isocratic HPLC in an ammonia-modified aqueous ethanol silica system, PC and LPC lipid class peaks were well separated from other lipids incl. other phospholipids. Defatted lecithin samples can simply be dissolved and injected. However, a purified soyabean PC fraction of similar fatty acid composition is necessary for external standard calibration with Rl detection. Because of the requirement that the sample should dissolve in an aqueousethanol mobile phase, the applications of this method is limited to defatted high grade lecithins (ca. 60-100% PC). A “detection limit” can therefore not be given.     

Effect of processing parameters on sunflower phosphatidylcholine‐enriched fractions extracted with aqueous ethanol

Lecithins are widely used in the food industry because of their multifunctional characteristics. Fractionation of the original mixture of phospholipids in lecithin is desirable for certain applications. The influence of ethanol/water mixtures (90 : 10 to 96 : 4) and other operative conditions (temperature 35–65 °C, incubation time 30–90 min, solvent/lecithin ratio 2 : 1, 3 : 1) on the extraction of phosphatidylcholine (PC)‐enriched fractions of sunflower lecithin (a non‐GMO product) was investigated. Yield % and phospholipid composition of the enriched PC fractions as well as the residue were determined. The percent extraction coefficient of each phospholipid (E_PC, E_PE and E_PI) in the enriched PC fraction was calculated. Values of E_PC varied from 6.5 (35 °C, 30 min, 2 : 1, 90 : 10) to 52.6 (65 °C, 90 min, 3 : 1, 96 : 4). High temperature and long incubation time produced a significant increase of this coefficient (p <0.05) while a high water content in the ethanolic mixture resulted in a considerable decrease in PC extraction. E_PI (<3%) values showed the high insolubility of phosphatidylinositol. Statistical analysis and response surface methodology evidenced the influence of the different variables on the extraction of PC‐enriched fractions at laboratory scale.     

Enzymatic preparation of L‐α‐glycerylphosphorylcholine in an aqueous medium

L ‐α‐Glycerylphosphorylcholine (L ‐α‐GPC) was successfully prepared from phosphatidylcholine (PC) of food‐grade soy lecithin powder using a novel enzymatic reaction in an aqueous medium. 94.5% yield of L ‐α‐GPC was obtained under the optimal conditions of 55°C, 6.67 mg/mL substrate, 2 mM CaCl₂, and 33.4 U/mL phospholipase A₁ (Lecitase Ultra). L ‐α‐GPC at 98% purity, 73.4% (wt%) recovery, and specific rotation ( ) of ?2.5° was achieved by silica gel column chromatography. Owing to its excellent catalytic efficiency, low cost, and ready availability, phospholipase A₁ (Lecitase Ultra) provides a very satisfactory option for converting PC to L ‐α‐GPC. Practical applications: L ‐α‐Glycerylphosphorylcholine (L ‐α‐GPC) has been studied recently for its potential use as a supplement that may support neurological functions, but it is only found in trace amounts in nature. The present results indicate that Lecitase Ultra can be used for producing L ‐α‐GPC from aqueous PC and suggest encouraging prospects for practical or industrial applications utilizing its notable catalytic performance, economy, and convenience.     

Optimization of multi-stage countercurrent extraction of antioxidants from Ginkgo biloba L. leaves

Multi-stage countercurrent extraction (MCE) as a novel extraction technique was used to extract antioxidants from Ginkgo biloba leaves. Orthogonal array design (OAD) was employed to optimize the ratio of 60% ethanol to raw material (8–16 mL/g), extraction time (30–60 min) and extraction temperature (60–80 °C) to obtain a high yield of antioxidants from G. biloba leaves by MCE. The optimum conditions were a ratio of 60% ethanol to raw material of 16 mL/g and extraction time of 30 min at 80 °C. Under these conditions, the yields of flavonoids and total phenolics were 1.74% and 2.42%, respectively, and DPPH radicals scavenging activity of the extract was 89.97%. Compared with heat-reflux extraction, MCE had obvious advantages of less extraction time and lower solvent and energy consumption. It may be used as a promising technique for the extraction of bioactive compounds from plant materials.     

高PC含量的大豆磷脂的制备研究

提出了制备高磷脂酰胆碱 (PC)含量的大豆磷脂的新工艺。用异丙醇作溶剂 ,通过正交实验得出优化的分离条件为 :抽提时间 5min ;抽提温度 - 5℃ ;m(磷脂 )∶m(异丙醇 ) =12∶15 7;异丙醇的体积分数 φ(异丙醇 )≈ 10 0 % ;HPLC分析结果表明 ,抽提后产品中PC的含量可以从原料中的w(PC) =2 5 6 %提高到w(PC) =6 6 8%。收率为 2 2 4%。     

A simple and cost-effective gram-scale chromatographic method for the purification of soybean phospholipids

A method was developed for the preparative fractionation of soybean lecithin to enable the study of the functional properties of pure soybean phospholipids. Hereby, a coarse and irregularly shaped silica gel was used as the stationary phase, whereas the mobile phase consisted of three mixtures of hexane, 2-propanol, and water with increasing polarity. These solvents were included in a step gradient, which was formed by an isocratic pump connected to a solvent switcher. With this system, two grams of soybean lecithin were fractionated. The purity was evaluated by analytical high-performance liquid chromatography, and the recovery was estimated from concentration determinations by flow injection analysis. From these results, it was concluded that 60 to 75% of the three major soybean phospholipids could be recovered with a purity of at least 93%. Only 1.5 L of solvents were needed for both the column equilibration and the elution of all soybean phospholipids. Senior research associate of the Belgian National Fund for Scientific Research (N.F.W.O.).     

聚碳酸酯在亚临界乙醇中的催化解聚

以氢氧化钠为催化剂、在投料比1∶6.3（20.0 g PC/126.2 g乙醇）、温度140～220℃、压力1.1～5.9 MPa、反应时间15～60 min条件下,利用间歇式高压反应釜研究了聚碳酸酯（PC）在亚临界乙醇中的催化解聚,产物分别采用傅里叶红外光谱（FT-IR）、气质联谱（GC-MS）和气相色谱（GC）进行分析。结果表明,PC的解聚率随温度的升高、反应时间的延长而增加;主产物双酚A（BPA）的收率随反应温度升高、反应时间延长而下降。在投料比1∶6.3、温度170℃、反应时间15 min、压力1.7 MPa、催化剂投加量1.0 g·（160.0 ml 乙醇）^-1条件下,PC解聚率为84.2%,BPA收率可达到95.7%。根据PC在亚临界乙醇中催化解聚产物的分析,并结合PC链结特点,提出了PC的催化解聚机理。通过实验数据关联,得出亚临界乙醇中PC催化解聚反应级数为一级,反应活化能为40.15 kJ·mol^-1。     

Structure development during dry–jet–wet spinning of acrylonitrile/vinyl acids and acrylonitrile/methyl acrylate copolymers

Dry–jet–wet spinning of three copolymers, poly(acrylonitrile/methyl acrylate), poly(acrylonitrile/methacrylic acid), and poly(acrylonitrile/itaconic acid), was performed with a dimethylformamide/water (60:40 v/v) coagulation bath at different temperatures (10–40°C). The fibers were stretched to different levels (1.1–6×) in boiling water, collapsed, and annealed over a heater plate at 130°C. The effects of the polymer composition, coagulation bath temperature, and draw ratio on the cross‐sectional morphology, structure, and tensile properties are reported. The cross‐sectional shape of the gel fibers underwent a transition from a kidney shape to an oval shape, and macrovoids began to appear at higher temperatures. However, F(AN/IA) gel fibers changed from a kidney shape to an irregular shoe type with a gel network of interconnected polymer fibrils. For F(AN/MAA) gel fibers, the diameter increased from 45 to 67 μm when the coagulation bath temperature was increased from 10 to 40°C, and the denier value decreased from 17.5 to 14.3 den/filament. The strength, modulus, and elongation at break decreased with an increase in the coagulation bath temperature. For F(AN/MAA) fibers coagulated at 10°C in a spin bath, the strength increased from 0.43 to 2.213 g/den, the modulus increased from 27 to 76 g/den, and the density increased from 1.177 to 1.196 g cm^?3 when the gel fibers were drawn to 6×. However, 6× drawn F(AN/MA) fibers had a higher strength (3.1 g/den) and elongation (14.6%) in a 40°C coagulation bath. F(AN/IA) fibers could be drawn only to a draw ratio of 4× instead of the 6× draw ratio for F(AN/MAA) and F(AN/MA) fibers. Therefore, the final F(AN/IA) fibers exhibited poor mechanical properties (tenacity = 0.81 g/den, modulus = 22 g/den, and elongation at break = 8%). The crystallinity did not change significantly (χ_c = 61–63%) with the draw ratio, but the crystal size increased from 22.9 to 43.4 Å and orientation factor from 0.41 to 0.78. The dichroic ratio, measured with Fourier transform infrared, decreased with an increase in the draw ratio, but the sonic modulus and crystalline orientation values increased with an increase in the draw ratio. Thermomechanical data show a maximum physical shrinkage of 51.7% for 6× drawn F(AN/MA) and a minimum physical shrinkage of 30.5% for 4× drawn F(AN/IA) fibers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 773–787, 2002