Triacylglycerols fatty acid composition

Table 2 Sodium chloride effect on triacylglycerols fatty acid composition in fully ripe olive fruits ...

Fats are solid triacylglycerols, oils are liquid triacylglycerols it is the fatty acid composition of the triacylglycerol that determines its physical properties. Triacylglycerols with a high proportion of unsaturated fatty acids have lower melting points than those rich in sam-rated fatty acids, so the former are oils - that is, they are liquid at room temperature. The unsaturated fatty acids are identified by the number of carbon atoms and the position of the double bonds (see below). 

Laurie acid incorporation. Laurie acid (50%) from the oil, administered to rats for 6 weeks, produced no significant difference between the experimental distribution of triacylglycerol types and the random distribution, calculated from the total fatty acid composition . 

Data on the proportions of different fatty acids in plasma lipid esters (cholesteryl esters, phospholipids, free fatty acids, or triacylglycerol), erythrocyte membranes, or adipose tissue may provide a more objective and accurate path to evaluating dietary fatty acid composition (Arab, 2003 Baylin and Campos, 2006). The fatty acid composition in blood and body tissues reflects the fatty acid composition of the diet at different time points after ingestion. Short and medium-term changes in the composition of dietary fatty acid intake are reflected in plasma lipids and erythrocyte membranes, weeks and months after intake, respectively. The incorporation of fatty acids in adipose tissue reflects long-term changes in the diet (years) (Baylin and Campos, 2006 Katan et al., 1997 Ma et al., 1995 Zock et al, 1997). 

Consequently, a more objective way to measure the habitual intake of milk fat would be the fatty acid composition of adipose tissue. However, this is not routinely performed in larger cohort studies, due to cost and that the procedure is invasive and less tolerated by study participants. Analysis of plasma fatty acid composition is thus a more feasible option for examination to determine dairy intake in the study population. While some groups have separated plasma into its constituent phospholipids and cholesterol esters to analyze serum 15 0 and 17 0 as markers of dairy intake (Smedman et al., 1999), Baylin et al. (2005) found that plasma that was not separated into its constituent cholesteryl ester, phospholipids, and triacylglycerols was still able to reflect habitual dairy intakes comparably to adipose tissue. Thus, whole plasma is an acceptable alternative to fractionated plasma in the absence of adipose tissue for analysis to reflect habitual dairy intakes and may be a cost effective option for consideration when conducting future intervention studies to assess the affect of dairy products on health outcomes. 

DAG species are derived from three main routes (1) PLC-mediated hydrolysis of phospholipids (2) phosphatase-mediated hydrolysis of phosphatidic acid (PA) and (3) lipase-mediated hydrolysis of triacylglycerol (TAG) species (Fig. 2). Targeted lipidomic analyses show that the fatty acid compositions of the DAGs formed by these various routes reflect the composition of the parent lipid (Fig. 5). In particular, those derived from inositol phospholipids are highly enriched in... 

Neri, A., Simonetti, M.S., Cossignani, L. and Damiani, P. (1998) Identification of cocoabutter equivalents added to cocoa butter-I. An approach by fatty acid composition of the triacylglycerol sub-fractions separated by Ag+-HPLC. Z. Lebensm. Unters. Forsch. A., 206(6), 387-392. 

The major differences between the lipids of bovine and human milk are in fatty acid composition and triacylglycerol structure. Bovine milk contains substantial quantities of C4 o-Ci0 o, about 2% Cis 2 and almost no other long-chain polyunsaturated fatty acids. The fatty acid composition is not altered by ordinary changes in diet. Human milk contains very little C4 o-C10 o, 10-14%i (w/w of fat) Ci8 2, and small quantities of other polyunsaturates. The triacylglycerol structure differs, with much of the sn-2 position in human milk lipids occupied by C16 0 and the sn-2 position of bovine milk-fat occupied by C4 o-Ci0 o-... 

The melting behavior of triacylglycerols generally reflects that expected from the fatty acid composition triacylglycerols rich in long-chain and saturated acids... 

Almond Prunus dulcis, P. amygdalis, Amygdalis communis). Almond oil is generally considered as an oleic-rich oil (65-70%), but its fatty acid composition can vary widely. The triacylglycerol composition of the oil has also been reported. Low-saturated, high-monounsamrated oils show high oxidative and cold weather stability (i.e., they are slow to deposit crystals) (65, 66). 

Natural oils and fractionated oils usually have their acyl chains organized in a nonrandom manner, but they become randomized after interesterification with a chemical catalyst. There is no change in fatty acid composition, only in triacylglycerol composition, but this leads to a modification of the physical properties. More selective interesterification can be achieved with enzymic catalysts (Section 8.5). 

Finally, genes required for particular aspects of fatty acid and triacylglycerol biosynthesis can be identified in appropriate sources, cloned, and transferred to other plants. Rapeseed has proved to be particularly flexible in this respect, and its fatty acid composition has been modified in several ways, some of which have now reached or are very close to commercial application (Section 9.4). Genetic modification procedures are also applied to soybean and other oilseed crops. 

As expected from fatty acid composition, the main triacylglycerols contain linolenic acid in their molecules and 84% of all triacylglycerols have this acid in their structure (Table 3). Among them, 21% of total acylglycerols contained three ALA in molecule, second by contribution were acylglycerols with two ALA, and linoleic acid had the second-most abundant fatty acid present in the flax oil (17). 

The fatty acid composition of rice bran oil is most similar to peanut or ground nut oil (Table 14) (8). Palmitic, oleic, and hnoleic acids make up more than 90% of the fatty acids present. The major molecular species of triacylglycerols are palmi-tic-linolenic-oleic, oleic-linoleic-palmitic, pahnitic-hnoleic-linoleic, hnolenic-lino-leic-palmitic, and trioleic. As with peanut oil, rice bran oil is most suited for general frying and cooking applications. 

The fatty acid composition of soybean oil changes considerably with maturity and with seed oil deposition (15, 35, 43, 44). In typical soybean triacylglycerols, the palmitate and linolenate tend to decrease with maturity, whereas hnoleate increases. Oleate tends to increase to a maximum and then dechne slightly. Soybeans selected for atypical fatty acid compositions show quite different patterns of change with maturity from typical soybeans. 

Harp and Hammond (45) explored the stereospecific distribution of acyl groups on the three positions of the glycerol molecule for soybean triacylglycerols with a wide range in fatty acid composition. They found that the amount of an acyl group... 

Neff et al. (48, 49) partially separated the triacylglycerols of soybean oils with a wide range of fatty acid compositions using high-performance liquid... 

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