Phytosterol distribution

Table 6.5 Distribution of simple phenols and phytosterols in Todaroa aurea (from Gonzalez etal., 1988)...

Nissinen, M., Gylling, H., Vuoristo, M., and Miettinen, T.A. 2002. Micellar distribution of cholesterol and phytosterols after duodenal plant stanol ester infusion. Am. J. Physiol. Gastrointest. Liver Physiol. 282, G1009-G1015. 

Sanders, D. J., Minter, H. J., Howes, D., and Hepburn, P. A. (2000) The safety evaluation of phytosterol esters. Part 6. The comparative absorption and tissue distribution of phy-tosterols in the rat. Food Chem. Toxicol. 38, 485 91. 

Assay Not less than 86.0% of Vegetable Oil Phytosterol Esters and not more than 9.0% of free vegetable oil sterols, the sum not less than 95.0%. Not less than 59.0% of des-methyl-sterols. Not more than 5.0% of acyl-glycerides. The vegetable oil sterols in Vegetable Oil Phytosterol Esters show the following typical distribution ... 

Dealkylation of phytosterols to cholesterol is now well known in insects and crustaceans. The transformation of [ H]fucosterol into cholesterol and desmosterol was also observed in two species of molluscs [134]. Desmosterol is a widely distributed sterol in molluscs, and in some species the content is very high (30-35%) [127,135]. This sterol can be considered as the dealkylation product of 24-al-kylsterols, and it is likely that desmosterol accumulates because of low activity of the A -sterol reductase. The capacity for both alkylation and dealkylation at the C-24 position in molluscs remains to be clarified. 

Table 7.6. Distribution (%) of Phytosterols in Free and Esterified Fractions from Soybean OiP ...

Fig. 7.10. Distribution (%) of soybean oil phytosterols after various stages of processing (Ferrari et al., 1997).

Arena, E., Campisi, S., Fallico, B., and Maccarone, E., Distribution of fatty acids and phytosterols as a criterion to discriminate geopraphic origin of pistachio seeds, Food Chem., 104, 403-408, 2007. 

Schottenol Sa-stigma-7-ene-3p-ol, a widely distributed phytosterol (see Sterols), M, 414.72, m.p. 151 °C, isolated, e.g. from the cactus Lophocereus schottU. S. is an essential dietary constituent for the insect Drosophila pachea, which lives on this plant. 

This phytosterol is widely distributed in brown algae, bacteria and higher plants. It is important as the precursor of ergocalciferol or vitamin D2, into which it is converted by ultraviolet irradiation. The change is the same as that which takes place in the formation of vitamin D3 from 7-dehydrocholesterol and involves opening of the second phenanthrene ring. 

It can be assumed theoretically that cycloartenol or its low polar analogs occur in all plants, since they are biogenetic precursors of phytosterols, which act as structural elements of cell membranes. Polyhydroxylated, highly oxidized, and glycosylated compounds are much less distributed. 

Cycloartenol is an important type of stanol found in plants. The biosynthesis of cycloartenol starts from the triterpenoid squalene. It is the first precursor in the biosynthesis of other stanols and sterols, referred to as phytostanols and phytosterols in photosynthetic organisms and plants. The identities and distribution of phytostanols and phytosterols is characteristic of a plant species. One notable product of cycloartenol biosynthesis is the triterpenoid lanosterol. 

Phytosterols (PS) are plant sterols and stanols widely distributed in plant sources that resemble cholesterol in terms of structure and physiological functions. The cholesterol-lowering capacity of PS is well documented in animal and human studies. However, recent studies suggest that the beneficial effects of PS are not only limited to their hypocholesterolemic capacity as they can also act as immunomodulatory, anti-inflammatory, and antidiabetic agents. Further, there is a growing body of evidence which supports that they play an important role in the prevention of other diseases such as cancer and atherosclerosis. Nevertheless, the mechanisms by which PS exert their beneficial functions, the physiological relevance of PS, and their potential adverse effects are not yet fully understood. Therefore, the main aim of this chapter is to provide a contemporaneous overview of the beneficial properties of PS, their mechanism of action, and safety. 

The concentration of sterols, di- and triglycerides in the extract fractions was lower than the respective feed concentrations under all of the investigated operating parameters the distribution of other components was affected by fractionation time, temperature and pressure. The volatiles were enriched up to a factor of 6.3, but the decrease in volatile concentration with time resulted in concentrations lower than the feed values in the latter fractions. The free fatty acids were enriched in the latter fractions relative to their concentration in the feed. Semi-continuous processing of the deodorizer distillate at 25 MPa and 70-100°C yielded a residue containing 40% sterols and this study highlights the value of using the canola deodorizer distillate as a source for the extractiou of phytosterols. 

Phytosterol ethoxylates (Figure 3.6) obtained by reaction of sterols with ethylene oxide in the presence of catalysts were produced in the early 1980s, for use mainly as emulsifiers in cosmetics [34, 35, 37]. Plant sterol ethoxylates are produced with an average degree of ethoxylation from 5 to 30 [38], but with a very broad homologue distribution. 

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