Lecithins classification

A method for classifying lecithin to include modified and refined forms has been proposed by Cowell et al. (55). This classification distinguishes between natural (crude) lecithins and those modified by either custom blending or chemical/enzy-matic treatment, e.g., hydroxylation, hydrogenation, acetylation, or refining by acetone or alcohol fractionation. These latter products reflect the state of the art regarding the availability of the various lecithin products on the market and have enhanced properties for specific uses. A listing of soybean lecithin classifications follows (56). 

The classification of a phosphatidyl ester depends on the nature of the second alcohol esterified to the phosphoric acid. Some of the most important lipids in this class are phosphatidyl ethanolamine (cephalin), phosphatidyl serine, phosphatidyl choline (lecithin), phosphatidyl inositol, phosphatidyl glycerol, and diphosphatidyl glycerol (cardiolipin) (Figure 8.5). In each of these types of compounds, the nature of the fatty acids in the molecule can vary widely. All... 

Classify lipids both into the large classifications (such as simple lipids, complex lipids, phospholipids, etc.) and into the more specific classifications (such as waxes, triglycerides, cephalins, lecithins, steroids, prostaglandins, terpenes, etc.). 

Fats Giucoiipids Gaiactoiipids Lecithins Fig. 3.1 Classification of the lipids. 

The initial step in the fabrication of a multiple emulsion (W/OAV) is to prepare a primary emulsion (W/0). It is generally agreed that the surfactant for the primary emulsion should have an HLB value of 3-6 (in the hydrophilic-lipophilic balance system of surfactant classification). Surfactants that have successfully been utilized include Span 80 (sorbitan oleate Nianxi et al, 1992 Zheng et al, 1993 Omotosho et al, 1990), E644 (polyamine Nianxieia/., 1992),N205 (polyamine Nianxi eta/., 1992), TX-4 (polyoxyethylene aUcylphenol ether Nianxi et al, 1992), MO A3 (polyoxyethylene aliphatic alcohol ether Nianxi et al, 1992), Brij 93 (Nianxi et al, 1992), polyoxamers [poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer Law et al, 19861, and egg lecithin. The surfactant or combination of surfactants is then dissolved in the oil... 

To better identify the boundaries of the oil-in-water phase and how its characteristics vary with small fluctuations in composition, we extended our analyses of the ternary phase diagram to include more detailed characterization of each phase and a higher resolution map of the oil-water phase. Two lipids— DOPA, an anionic lipid, and lecithin, a zwitterionic neutral lipid—were compared to determine the effect of lipid head group. Five different characterization methods were employed (1) visual classification of the phases, (2) buoyant density, (3) fluorescence quenching, (4) FT-IR, and (5) Cryo-TEM. The rationale for each technique is summarized in Table 15.2. A flow chart for utilizing the information obtained from these methods was developed to objectively evaluate the oil-in-water phase (Fig. 15.5). 

Choline, which is a key part of the constituent of lecithin is vital for the prevention of fatty livers, the transmitting of nerve impulses, and the metabolism of fat The classification... 

Recently, Bernheimer (7) has studied the kinetics of red cell lysis by a number of hemolytic agents, several of which were of bacterial origin. The results provide a basis for classification of hemolysins. Thus the maximum rate of hemoglobin liberation was found to be a linear function of concentration for pneumolysin, tetanolysin, streptolysin S and toxin. With saponin, various detergents such as cetylpyridinium chloride and tyrocidine and with lecithin-airoa venom mixture or strep-... 

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