超临界CO2萃取制备卵黄磷脂

采用超临界CO2萃取蛋黄粉中的蛋黄油及用食用酒精萃取卵磷脂，在较温和的工艺条件下制备卵黄磷脂。     

蛋黄磷脂的制取方法及有关问题

本文介绍了从蛋黄中用溶剂提取蛋黄磷脂的方法，并且详细讨论了提取磷脂用溶剂及分离等有关问题。     

磷脂种类对于番茄红素磷脂复合物的溶解度的影响

目的采用不同种类的磷脂制备番茄红素磷脂复合物,并对不同种类的番茄红素磷脂复合物的理化性质进行比较。方法采用摩尔系数法确定番茄红素跟磷脂的最佳复合比,以复合率为指标采用正交试验确定最佳的制备过程,同时测定番茄红素和不同磷脂形成的磷脂复合物的溶解度和油水分配系数。结果采用蛋黄卵磷脂制备的番茄红素磷脂复合物的溶解性的改善程度较采用大豆磷脂制备的磷脂复合物更高,采用纯度较高的磷脂制备的番茄红素磷脂复合物具有更好的溶解性。结论番茄红素与蛋黄卵磷脂复合后更能够增加番茄红素的溶解性,高纯度的蛋黄卵磷脂增加番茄红素的溶解性更明显。     

国内外卵磷脂生产及应用概况

一、概况卵磷脂又称大豆磷脂,天然存在于蛋黄、菜籽、大豆、向日葵籽、某些谷物中,另外在动物和人类大脑中也有少量存在。卵磷脂于19世纪首先在蛋黄中被发现。但实际具备商业用途的是大豆中所含的卵磷脂,在食品中应用已有60多年历史。大豆磷脂是由一些具有表面活性的物质组成的混合物。其主要成分是,磷脂酰胆碱(PC,也称卵磷脂)、磷脂酰乙醇胺(PE,也称脑磷脂)、磷脂酸(PA)和磷脂酰肌醇(PI)等。结构式如图1所示。     

磷脂与食品工业

一、磷脂的存在及其生理功能磷脂系构成动植物细胞的成份。在动物的卵、脑、心、肺、肝、肾、骨髓等组织和植物体的全部活细胞中尤多。动物的干蛋黄中含卵磷脂为9.4％,而牛脑髓中含脑磷脂为6.0％,植物油脂中含量不尽相同(见表)。     

用超临界二氧化碳萃取技术制备蛋黄卵磷脂的几种工艺探讨

介绍了蛋黄卵磷脂的功能用途、市场需求和生产工艺,对用超临界CO2萃取技术制备蛋黄卵磷脂的几种典型工艺进行了归纳、分析和比较,指出这些工艺产业化过程中存在的问题,并给出一些初步解决的方案。     

几种国外化妆品简述

高效护发制剂日本公开特许提出一种头发洗后使用的护发剂。这种护发剂含有0.1～20％磷脂(大豆油磷脂、蛋黄磷脂等)和天然植物油(橄榄油、大豆油、玉米油、扁桃油、向日葵籽油、核油等)的络合物。磷脂和天然油脂之比为1:9～9:1。在护发乳液中采用1％卵磷脂、1％大豆油、5％丙二醇,加水至100％。为固定发型,改善头发的结构和外观,在配制护发剂时建议采用0.1～10％(最好0.1～2％)磷脂和0.1～10％(最好0.1～5％)氨基酸。上述物质比例为1:9～9:1。这种护发乳液的配方如下:卵磷脂1％,     

蛋黄卵磷脂制备工艺及超临界CO_2脱蛋黄油实验研究

对用超临界CO_2萃取技术制备蛋黄卵磷脂的几种典型工艺进行了归纳、分析和比较。根据选择的工艺,对关键设备萃取器料筒进行了改进,通过正交试验,探讨了萃取压力、温度、时间、料筒层数等条件对蛋黄油脱除率的影响规律。     

丹酚酸B磷脂复合物的制备和质量评价

探讨了丹酚酸B磷脂复合物的制备最佳工艺条件。以丹酚酸B与磷脂的复合率为评价指标,考察反应溶剂、反应温度、反应时间、初始浓度和投料比对复合率的影响,采用正交实验筛选出最佳制备工艺,并通过差示扫描量热法、红外光谱、透射电镜以及泡沫细胞渗透性实验验证磷脂复合物形态及性质。确定丹酚酸B磷脂复合物制备的最佳工艺为:反应溶剂为四氢呋喃,反应温度40℃,反应时间3 h,丹酚酸B反应浓度为25 mg·m L-1,丹酚酸B与磷脂投料比为1∶1,差示扫描量热法、红外光谱、透射电镜以及泡沫细胞渗透性等实验均证实了磷脂复合物的形成和优良特性。成功制备了丹酚酸B磷脂复合物,复合率可达99.5%。     

非天然磷脂化合物磷脂酰基γ-羟基丁酸的合成

首次利用生物酶催化法对非天然磷脂化合物磷脂酰基γ-羟基丁酸(phosphatidylbutyricacid,PB)的合成工艺进行了系统的探究。采用磷脂酶D(phospholipaseD,PLD)在有机溶媒-水两相体系中催化磷脂酰胆碱(phosphatidylcholine,PC)和γ-羟基丁酸钠(sodiumγ-hydroxybutyrate)发生磷脂酰基转移反应合成PB。实验结果表明,有机溶媒、底物摩尔比、反应温度、水相pH都对磷脂酰基γ-羟基丁酸的制备有一定的影响。确定最佳工艺为:以氯仿为有机溶媒,底物摩尔比(γ-羟基丁酸钠/PC)为90∶1,反应温度为30℃,水相pH为5.5,反应时间为6h,在此工艺条件下的磷脂酰基γ-羟基丁酸的产率为73.51%。     

A Simple Enzymatic Approach for Selective Acetylation of Phosphatidylethanolamine

Acetylation of lecithin improves the fluid properties, water dispersibility and emulsifying properties of a variety of food formulations. Acetylation of lecithin is usually carried out chemically using acetic anhydride in the presence of tertiary amine. In the present study acetylation of soybean lecithin and egg yolk lecithin was carried out using lipozyme IM 20 having 1,3-specificity from Mucor miehei and vinyl acetate at 70–75 °C. Vinyl acetate played a dual role as acetylating agent and also as the solvent medium. This method selectively acetylated phosphatidylethanolamine without effecting phosphatidylinositol since the enzyme employed was 1,3-specific.     

Extraction of Phospholipids from Egg Yolk Flakes Using Aqueous Alcohols

Two alcohols, ethanol and butanol, with different water contents were evaluated for phospholipids (PL) sequential extraction from drum dried egg yolk flakes. It showed that butanol was more effective in extracting total yolk lipids compared to ethanol, but the PL in the extract had the same concentration as in the original yolk total lipid. The use of aqueous ethanol of 95 and 75% resulted in lipid extracts with higher PL concentration during the initial stages of the sequential extraction. When ethanol was further diluted to a concentration of 55%, the solvent lost its PL extraction ability, and the total lipid recovery also decreased dramatically. When both the PL purity and recovery were considered, 75% ethanol was the most effective aqueous alcohol for PL extraction and enrichment from the yolk flakes. In the first stage of extraction using such a solvent, 67% of the total PL in the original yolk was recovered in a lipid fraction with a PL purity of 75%. This study identified the optimal ethanol concentration for PL extraction from dried egg yolk. With this information, the best solid:solvent ratio can be designed to extract and enrich the polar lipids from lipid-bearing materials with known moisture content using a renewable or “green” solvent, ethanol.     

Laboratory Studies on Membrane Deoiling of Lecithin

Deoiling of lecithin using a nonporous membrane was examined in a favorable solvent (hexane) medium with soy and rice bran lecithins. During the membrane process, the acetone insoluble (AI) content of soy lecithin increased from 63.2 to 81.0% in a single step batch operation. The membrane exhibited an excellent selectivity since phospholipid (PL) reverse micelles formed in the system were rejected almost completely due to low solubility probably aided synergistically by size exclusion. Diafiltration achieved greater oil removal from lecithin as reflected in terms of higher AI and PL contents in the deoiled lecithin. In discontinuous diafiltration, the PL content increased from 33.3 to 85.5% in rice bran lecithin (150% dilution to feed) and 56.6 to 85.7% in soy lecithin (200% dilution), respectively. The simulated continuous diafiltration run showed slightly greater PL content in soy lecithin (91.3%) compared to discontinuous diafiltration (89.7%) besides offering higher productivity. The membrane showed a color reduction of ~60% in soy lecithin but there was no improvement in rice bran lecithin due to the retention of degradation products. The proposed integrated membrane process with nonporous (deoiling) and nanofiltration (solvent recovery) membranes could be an attractive preposition besides being an acetone free process.     

Formation of complexes between lecithin and apovitellenin I,an avian egg-yolk apoprotein

In a study of lipid-protein interactions in egg yolk, it was found that L-α-dipalmitoyl lecithin gave two distinct noncovalent complexes (A and B) with apovitellenin I, an apoprotein in the major yolk lipoprotein. Interaction took place under widely varied conditions, and yolk lecithin gave similar complexes. Complex A, which was formed within minutes, consisted of round particles of about 9 nm diameter. Complex B, which was formed more slowly, consisted of larger, particles. Possibly resembling curved discs, with diameter of 30–40 nm. The preparation and some properties of these complexes are described. It is suggested that they may be suitable for an extensive study of phospholipid-protein interactions in yolk.     

Extraction of phospholipids from structured dry chicken egg

Chicken egg contains a high level of phospholipids (PL) in the yolk. Recovering yolk total lipids and extracting egg PL with efficiency are important to the availability and utilization of these health‐promoting lipid products. In this study, we prepared two structured dry egg yolk materials and used two common solvents to extract and concentrate the PL. We found that drum‐dried flake‐like yolk is an ideal starting material for lipid extraction. Anhydrous ethanol can extract almost all the neutral lipids and PL. PL with purity over 90% can be prepared by cold acetone precipitation from the total lipids.     

Kinetic study of reactions between tocopheroxyl radicals and fatty acids

A kinetic study on the prooxidant effect of vitamin E derivatives has been carried out. Rates of hydrogen abstraction from various fatty acids and egg yolk lecithin by tocopheroxyl radicals were determined spectrophotometrically. The rate constants measured in micellar dispersion were compared with those obtained in homogeneous solutions. The effects of structural variations of the vitamin E derivatives on their prooxidant activities were examined. The formation of lecithin reverse micelles in benzene appears to prevent the tocopheroxyl radicals from reacting with the phospholipid fatty acid moieties.     

Extraction of Phospholipids from Structured Dry Egg Yolk

Chicken egg yolk is a concentrated source of phospholipids (PL). Extracting egg PL with high efficiency is vital to the availability and economics of this high-valued lipid product. In this study, two types of structured dry egg yolk materials, yolk flakes and pellets, were prepared. Two commonly used solvents, hexane and ethanol, were tested on the extraction of total yolk lipids including the PL. The PL fraction was obtained by the conventional cold acetone precipitation. The drum-dried yolk flakes were shown to be an ideal starting material for total lipid and PL extraction. Anhydrous ethanol can extract almost all the neutral lipids and PL with little change to the individual components of the native PL. A PL product with a purity of more than 90 % and a yield of 99 % can be prepared using this method.     

Antioxidant and ACE Inhibitory Bioactive Peptides Purified from Egg Yolk Proteins

Protein by-products from the extraction of lecithin from egg yolk can be converted into value-added products, such as bioactive hydrolysates and peptides that have potential health enhancing antioxidant, and antihypertensive properties. In this study, the antioxidant and angiotensin converting enzyme (ACE) inhibitory activities of peptides isolated and purified from egg yolk protein were investigated. Defatted egg yolk was hydrolyzed using pepsin and pancreatin and sequentially fractionated by ultrafiltration, followed by gel filtration to produce egg yolk gel filtration fractions (EYGF). Of these, two fractions, EYGF-23 and EYGF-33, effectively inhibited the peroxides and thiobarbituric acid reactive substance (TBARS) in an oxidizing linoleic acid model system. The antioxidant mechanism involved superoxide anion and hydroxyl radicals scavenging and ferrous chelation. The presence of hydrophobic amino acids such as tyrosine (Y) and tryptophan (W), in sequences identified by LC-MS as WYGPD (EYGF-23) and KLSDW (EYGF-33), contributed to the antioxidant activity and were not significantly different from the synthetic BHA antioxidant. A third fraction (EYGF-56) was also purified from egg yolk protein by gel filtration and exhibited high ACE inhibitory activity (69%) and IC₅₀ value (3.35 mg/mL). The SDNRNQGY peptide (10 mg/mL) had ACE inhibitory activity, which was not significantly different from that of the positive control captopril (0.5 mg/mL). In addition, YPSPV in (EYGF-33) (10 mg/mL) had higher ACE inhibitory activity compared with captopril. These findings indicated a substantial potential for producing valuable peptides with antioxidant and ACE inhibitory activity from egg yolk.     

Isolation of Pure Phospholipid Fraction from Egg Yolk

The phospholipid (PL) fraction from egg yolk was isolated and purified. In the procedure applied (method 2) the egg yolk was extracted with ethanol, precipitated using acetone chilled to −20 °C and washed using acetone. The purity of the samples was checked by HPLC analysis using a Charged Aerosol Detector (CAD). The results were compared with those obtained for the phospholipid fraction isolated and purified by deoiling yolk before extraction and the precipitation of PL with acetone chilled to 4 °C (method 1). The use of acetone chilled to −20 °C to precipitate and wash the phospholipids yielded the phospholipid fraction with 100% purity (78.7 ± 0.2 of phosphatidylcholine and 21.3 ± 0.2 of phosphatidylethanolamine). When deoiling and the 4 °C purification process was used (method 1) 0.4 ± 0.1% cholesterol and some traces of triacylglycerols remained in the PL fraction.     

Simultaneous extraction and preparative fractionation of egg yolk lipids using the principle of adsorption

A new approach describing the simultaneous extraction and preparative fractionation of egg yolk lipids is described, a method which can be extended to other tissues. In this method, egg yolk is adsorbed on activated thin layer chromatography grade silicic acid and sequentially extracted with different solvents to get a crude fractionation of its lipids into nonpolar and polar components. These crude concentrates help achieve larger yields of high purity lipids per unit column load during subsequent chromatographic subfractionation.