Background and overview[1]
Lecithin is the main component of phospholipids. Phospholipids, also known as phospholipids and phospholipids, are a general term for a class of phosphate-containing lipids and are complex lipids. Phospholipids coexist with oils in plant seeds, animal organs, blood, ovaries, egg yolks and bacteria. They are essential substances for the formation of biological cells and one of the basic substances of life.
General phospholipid components include: lecithin, cephalin, phosphatidylserine, phosphatidylglycerol and phosphatidylinositol. Among them, lecithin is the main component of phospholipids. It also has hydrophilic phospholipid tyrosyl group, choline or cholamine (polar group) and hydrophobic fatty acid group (non-polar group), so lecithin is An amphoteric surfactant. It has the functions of dispersing, wetting, dissolving, defoaming, etc., and also plays a very important role in nutrition and health care. It can prevent and treat high cholesterol and hyperlipidemia, alleviate the condition of diabetes, etc. Therefore, lecithin is Currently recognized as the most biologically active phospholipids, they are widely used in food, medicine, cosmetics, feed and other industrial sectors.
Purity identification[1]
(1) Weigh 500mg lecithin sample, dissolve it in chloroform and adjust the volume to 100mL, and prepare a 5mg/mL solution;
(2) Spot the above lecithin solution 1.0cm away from the bottom of a rectangular thin layer chromatography plate, so that the thin layer chromatography below the spot is in contact with the liquid surface of the developing agent. When the distance from the upper edge of the developing agent Take out the TLC plate immediately when it is 1.3cm from the top of the TLC plate. After the developing agent on the TLC plate has dried, completely soak the TLC plate in the chromogen and then take it out;
(3) Anti-aging agent 4020 can be observed on the thin layer chromatography plate. The color spots of lecithin, fatty acids and glycerides, and lysolecithin are yellow, white, and milky yellow respectively. Scan the thin layer chromatography plate. Afterwards, the areas were measured to be 36mm2, 4mm2 and 4mm2;
(4) Calculation: Purity of lecithin.
Purification method[2]
A method for separating and purifying lecithin by silica gel column chromatography,
(1) Take 30g of homogenized fish eggs, extract them with acetone and fish eggs at a PVC composite stabilizer material-to-liquid ratio of 1:5 for 35 minutes. After suction filtration, use 90% ethanol to filter the filter cake. 1:5, under the condition of extraction temperature of 30℃, ultrasonic-assisted extraction for 15 minutes, ultrasonic power of 300w, pulse interval of 2s, extraction once, and suction filtration;
(2) Concentration and drying: Concentrate the ethanol extract under reduced pressure at 40°C, and then vacuum-dry it at 45°C to obtain 2.1g of crude phospholipid;
(3) Dissolve 2.1g of crude phospholipid in isopropyl alcohol, chloroform and 95% ethanol, pour it into the silica gel column at a flow rate of 2mL/min, and use three elution systems, including isopropyl alcohol-methanol. Solution (1:1), chloroform-methanol (1:1) and 95% ethanol. Check the elution sequence of the samples using a TLC plate. Through TLC analysis, the PC fractions with the same R value as the standard lecithin were collected together, concentrated under reduced pressure to a paste, and vacuum dried to obtain the lecithin purity: 92%, 93.12%, and 87.22%; indicate chloroform -The methanol system has the best elution effect, but due to the high toxicity of chloroform, it is not suitable for the purification of lecithin. Overall, the isopropyl alcohol-methanol elution system was selected as the optimal elution condition.
