Partial glycerides

Partial glycerides tend to melt higher than thek triglyceride counterparts, as shown in Figure 6. This observation is consistent with the presence of free hydroxyl groups which can participate in increased intermolecular hydrogen bonding. 

The ester class also comprises natural oils, such as vegetable oil [75] spent sunflower oil [940,941,992,993] and natural fats, for example, sulfonated flsh fat [161]. In water-based mud systems no harmful foams are formed from partially hydrolyzed glycerides of predominantly unsaturated Ci6 to C24 fatty acids. The partial glycerides can be used at low temperatures and are biodegradable and nontoxic [1280]. A composition for high-temperature applications is available [1818]. It is a mixture of long chain polyesters and polyamides. 

Partial enzyme inhibition, 10 318, 320 Partial glycerides, 10 802-804 Partial immersion thermometers, 24 464 -465... 

Lipase Triglycerides + HzO -> fatty acids + partial glycerides + glycerol Off flavours in milk flavour development in Blue cheese... 

Fat Derivatives (partial glycerides, fatty alcohols, fatty acids, alkylpolyglucosides) and... 

Gas-Liquid Chromatography. Gas-liquid chromatography (GLC) affords both a qualitative and, if adequate internal standards are used, a quantitative analysis of the products of lipolysis. It is necessary, however, first to isolate the acids by a suitable method and then to inject them as free acids or as esters. The partial glycerides can be isolated by thin-layer chromatography and can also be determined by GLC of suitable derivatives. The acid(s) remaining in the partial glycerides can be identified readily by GLC following transesterification. Jensen and co-workers have utilized these techniques in their studies of lipase specificity (Jensen et al 1964). 

The triglyceride chromatograms for palm olein solid fractions collected after 12,15,18, 21, and 24 h at low-temperature (12.5°C) storage were very similar. The unidentified peaks that appeared in the early region of the chromatograms were expected to be of partial glycerides. Evidence of a stable and straight baseline and the sharp and symmetrically defined peaks show the... 

Glowacz et al. (1996) Batch Hydrolysis of triolein and its partial glycerides Porcine pancreatic lipase... 

There are many pharmaceutical applications for the modification of one enantiomer over another, and to this end, many have studied these selective reactions in carbon dioxide. Glowacz et al. (1996) studied the enzymatic hydrolysis of triolein and its partial glycerides and found that stereoselectivity depends on reaction time and enzyme water content. They suggest that the water content varies the local environment of the enzyme in carbon dioxide and changes the local pH value. Rantakyla et al. (1996) also found that the hydrolysis of one stereoisomer over another was water-dependent. They studied the hydrolysis of 3-(4-methoxyphenyl)glycidic acid methylester and found that the 2S,3R enantiomer hydrolyzed more than fivefold faster than the 2R3S form. 

Glowacz, G. Bariszlovich, M. Linke, M. Richter, P. Fuchs, C. Morsel, J. T. Stereoselectivity of Lipases in Supercritical Carbon Dioxide. I. Dependence of the Regio- and Enantioselectivity of Porcine Pancrease Lipase on the Water Content During the Hydrolysis of Triolein and its Partial Glycerides. Chem. Phys. Lipids 1996, 79, 101-106. 

Lipolysis, the enzymic hydrolysis of milk lipids to free fatty acids and partial glycerides, is a constant concern to the dairy industry because of the detrimental effects it can have on the flavor and other properties of milk and milk products. However, free fatty acids also contribute to the desirable flavor of milk and milk products when present at low concentrations and, in some cheeses, when present at high concentrations. 

Fatty acid ethoxvlates Fatty acid esters Partial glycerides Triacetin... 

Diacetyl Tartaric Acid Esters of Mono- and Diglycerides occur over a range in appearance from sticky, viscous liquids through a fatlike consistency to a waxy solid, depending on the iodine value of the oils or fats used in their manufacture. They are the reaction product of partial glycerides of edible oils, fats, or fat-forming fatty acids with diacetyl tartaric anhydride. The diacetyl tartaroyl esters are miscible in all proportions with oils and fats. They are soluble in most common fat solvents, in methanol, in acetone, and in ethyl acetate, but are insoluble in other alcohols, in acetic acid, and in water. They are dispersible in water and resistant to hydrolysis for moderate periods of time. The pH of a 3% dispersion in water is between 2 and 3. 

Sample Preparation (Caution To avoid rearrangement of partial glycerides, use extreme caution in applying heat to samples, and do not heat above 50°.)... 

Table 10-4 Formation of Partial Glycerides in Cheddar Cheese...

In order to obtain a commercial loading of the near-critical extractant, the extraction is sometimes carried out at enhanced pressures in the droplet regime. In such cases the liquid phase does not flow downwards as a film adhering to the packings of a column as is usually assumed, rather it falls down as a swarm of droplets. On the basis of the separation of a mixture of partial glycerides the behavior of packed columns in the droplet regime (instable flowing films) the efficiency of different column installations are compared. A mixture of 55 wt.% propane and 45 wt.% carbon dioxide is used as an extractant. 

Solid lipids, emulsifiers, and water are generally the ingredients involved for manufacturing SLNs. The term lipids is used in a broader sense and includes triglycerides (e.g., stearin), partial glycerides (e.g., Imwitor), fatty acids (e.g., stearic acid), steroids (e.g., cholesterol), and waxes (e.g., cetyl palmitate). All categories of emulsifiers may be used to stabilize the lipid dispersion, and the combination of emulsifiers prevents particle agglomeration more efficiently. The choice of the emulsifier depends on the administration route and is more limited for parenteral administration. 

As mentioned previously, partial glycerides are artifacts of the extraction process, especially the stages prior to sterilization. Oil obtained from unbruised sterilized fruits shows trace levels of partial glycerides. Random analyses of samples of refined palm oil, pahn olein, and palm stearin have shown the presence of about 2% of 1,2-diglycerides and about 4% of 1,3-diglycerides with trace amounts of monoglycerides. These partial glycerides are important as they are known to affect the crystallization behavior of the oil. 

By-products. Chemical Refining. The neutralization of free fatty acid in the crude pahn oil with caustic soda results in the formation of soapstock, which is treated with dilute sulfuric acid of pH 2.0-3.5 at 110-130°C for 30 min. A by-product called palm acid oil is then separated from the aqueous phase by centrifugation followed by hot-water washing. It consists mainly of free fatty acids, neutral oil, and partial glycerides. A small amount of unsaponifiable matter is also present. Characteristics and properties of palm acid oil (derived from chemical refining of crude pahn oil, stearin, and olein) are given in Table 35 (55). 

Water-dispersible lecithins may be produced by adding a hydrophilic surfactant (5-20%) such as polysorbate or ethoxylated monoglycerides. A mixture of lecithin and nonionic surfactants (10-20%) has utility in applications where water dispersibility is needed. Blending of partial glycerides and lecithin, followed by spray cooling, results in flaked or powdered products (33). 

Glowacz G, Bariszlovich M, Linke M, Richter P, Fuchs C, Morsel JT. Stereoselectivity of lipases in supercritical carbon dioxide. 1. dependence of the regio- and enantioselectivity of porcine pancreas lipase on the water content during the hydrolysis of triolein and its partial glycerides. Chem Phys Lipids 1996 79 101-106. 

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