Surface active phospholipid

Lipids exist in most foods as multiphased colloidal systems bound by surface-active phospholipids, proteins and emulsifiers. The oxidative stability of food lipids is greatly affected by the partitioning of the lipid substrates, metal initiators and antioxidants, which is complex and depends on the physical properties of the food. We may consider three types of food systems (see Chapter 10) ... 

Various other functions have been attributed to the surfactant proteins. Primarily among them is their role in tubular myelin formation in presence of calcium. It has been proposed that tubular myelin is the precursor to the surface active phospholipid monolayer, but investigations regarding this are incomplete. Collectively the results of studies on surfactant proteins suggest that these proteins may play a prominent role in the organization of the lipids in the ainivay. 

Schwarz, 1. M. and Hills, B. A. Surface-active phospholipid as the lubricating component of lubrician,... 

Purbach B, Mils BA and Wroblewdd BM (2002) Surface-active phospholipid in total hip arthroplasty. Clinical Orttu edics And Related Research, 396, 115-118... 

It appears that a substantial part of the airway surfactant is derived from the alveolar region, but there is also evidence for local production of surfactant. Widdicombe (41) reviewed the possible sources and potential biological role of tracheal surfactants. He concluded that the trachea contains a complex mixture of lipids, including surface-active phospholipids not characteristic of alveolar surfactant. Experiments (60) have shown that nonciliated cells of the bronchioles produce surface-active material and that these cells are involved in ion and water transport. Other studies (43) demonstrated phospholipids in secretory cells of airway submucosal glands, suggeshng local produchon of phospholipids in the... 

Widdieombe JG. Introduction. Endobronchial surface active phospholipids morphology, biochemistry, function and therapeutic aspects. Eur J Respir Dis 1985 ... 

In media selective for enterobacteria a surface-active agent is the main selector, whereas in staphylococcal medium sodium and lithium chlorides are the selectors staphylococci are tolerant of salt concentrations to around 7.5%. Mannitol salt, Baird-Parker (BP) and Vogel-Johnson (VJ) media are three examples of selective staphyloccocal media. Beside salt concentration the other principles are the use of a selective carbon source, mannitol or sodium pyruvate together with a buffer plus acid-base indicator for visualizing metabolic activity and, by inference, growth. BP medium also contains egg yolk the lecithin (phospholipid) in this is hydrolysed by staphylococcal (esterase) activity so that organisms are surrounded by a cleared zone in the otherwise opaque medium. The United States Pharmacopeia (1990) includes a test for staphylococci in pharmaceutical products, whereas the British Pharmacopoeia (1993) does not. 

Phospholipids are amphiphilic compoimds with high surface activity. They can significantly influence the physical properties of emulsions and foams used in the food industry. Rodriguez Patino et al. (2007) investigated structural, morphological, and surface rheology of dipalmitoylpho-sphatidylcholine (DPPC) and dioleoyl phosphatidylcholine (DOPC) monolayers at air-water interface. DPPC monolayers showed structural polymorphisms at the air-water interface as a function of surface pressure and the pH of the aqueous phase (Fig. 6.18). DOPC monolayers showed a... 

Other surface-active compounds self-assemble into bilayer structures (schematically illustrated in Fig. 10b), which normally spherilize into structures termed vesicles. When vesicles are formed from phospholipids, the term liposome is used to identify the structures, which also provide useful drug delivery systems [71]. Solutes may be dispersed into the lipid bilayer or into the aqueous interior, to be subsequently delivered through a variety of mechanisms. Liposomes have shown particular promise in their ability to act as modifiers for sustained or controlled release. 

The internal hydrophobic core of lipospheres is composed of fats and biodegradable polymers, mainly triglycerides and lactide-based polymers, whereas the surface activity of liposphere particles is provided by the surrounding lecithin layer, composed of phospholipid molecules. 

Bangham AD, Home RW. Negative staining of phospholipids and their stmctural modification by surface active agents as observed in electron microscope. J Mol Biol 1964 8 660-668. 

Formation of SA monolayers of phospholipids [217,242] and surface-active viologens [244, 245] on gold substrates, those of long-chain zirconium-phosphonates on silicon substrates [243], and those of alkanethiols on gallium arsenide substrates [246] have also been reported. 

Istarova, T.A., Semenova, M.G., Sorokoumova, G.M., Selishcheva, A.A., Belyakova, L.E., Polikarpov, Yu.N. (2005). Effect of pH on caseinate interactions with soy phospholipids in relation to surface activity of their mixtures. Food Hydrocolloids, 19, 429-440. 

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