Lecithins colour

Extraction with supercritical fluids (e.g., C02) 80-300 decaffeinated coffee (tea) spices, hops colours drugs oils, lecithine and fats tobacco (nicotine) perfumes... 

Chapters 1 and 6. PhosphoHpids have hydrophiUc polar heads and hydrophobic nonpolar tails and form reverse micelles in organic solvents such as hexane. Moreover, the micelles bind low molecular weight impurities such as free fatty acids, sugars, amino acids and colour compounds [33]. Because of the formation of micelles, triglycerides are also fractionated from phosphoHpids. The latter is then easily purified to produce a valuable product, lecithin, oil-free. Since the micelles are estimated to have pseudo-molecular weights of200,000, it should be possible, therefore, to recover lecithin oil-free using UF membranes with MWCO of >20,000. 

However, lecithin is usually added to margarine after hydrogenation, to act as an emulsifier in the final product which may then contain 0.1-0.5%. Modern margarine products usually contain various other additives such as vitamins, preservatives, colouring and flavouring agents and so on. 

A technique for the quantitation of coloured bands or spots on chromatograms or electrophoretic strips. Colour intensity can be measured by transmission, when light is allowed to pass through the sample, or by reflectance, when light is reflected from the coloured area. TTie coloured areas are represented as peaks on a chart recorder, and, from this, the area under each peak can be determined. In some instruments, the area under each peak is automatically integrated. Albumin in some laboratories is measured by densitometric techniques. Densitometers can also be used in the measurement of amniotic fluid lecithin sphingomyelin ratios. 

In Latin America and other continents batch driers are used, claiming that investments are low and that the drying at a maximum of 90 °C is efficient for lecithin with good colour. The De Smet type batch drier is made of a horizontal cylindrical jacketed body with a dome. Hot water circulates in the jacket. A heavy duty, rotating coil mounted on a shaft provides the necessary heat, while at the same time it agitates the lecithin gums. 

Standard refined lecithins take the largest share of the lecithin group of emulsifiers. The definition refining is mostly used for the exact adjustment of quality parameters of clear filtered lecithin with guaranteed AI, AV, colour and phospholipid composition. Thus it is a different definition compared to refining of oils. 

In principle chemical hydrolysis of the fatty acids from the phospholipid molecules is possible. However, this reaction is not applied on a plant seale, because enzymatic hydrolysis is the preferred state-of-the-art process. Chemical partial hydrolysis can be made with various strong acids, but the modified lecithins usually have a dark brown to black colour, forming an obstacle for successful industrial use in many applications. 

Crude lecithin is mixed with 2-14% hydrogen peroxide and 1% lactic acid at 50-60 °C. The lactic acid reduces the pH, which facilitates the reaction. Residual water is removed by drying. During the reaction the coloured components are bleached, which yields a light coloured lecithin. Hydroxylated lecithin is superior for emulsification of oil-in-water emulsions. It easily disperses in cold and water as a whitish emulsion. This is already a good indication that the HLB value increased significantly. 

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