Esterified sterol glycoside

The 3-hydroxyl group can also form a glycosidic link with the 1-position of a hexose sugar (usually glucose). Sterol glycosides are widespread in plants and algae and the 6-position of the hexose can be esterified with a fatty acid to produce an acylated sterol glycoside. 

Phytosterols The relationship between total dietary phytosterol content and the fatty acid composition of the diet decreases with increasing saturated fatty acids, whereas the total dietary phytosterol content increases with increasing PUFA (86). Phytosterols consist of a mixture of cell membrane constituents that include free sterols, esterified steryls (e.g., esterified to phenolics), steryl glycosides, and acylated steryl glycosides (Table 2). 

In Chapter 15, the biosynthesis of phytosterols was described. Briefly some of the major sterols found in plants are shown in Fig. 1. Principal differences are in the side chain (C20-CJ7) which has different degrees of substitution and unsaturation. The sterol derivatives, also shown in Fig. 1, are (1) steryl esters (SEs), in which a long-chain fatty acid is esterified at the 3-OH of the sterol, (2) steryl glycosides (SGs) in which the 3-OH of the sterol forms a glycosidic linkage to the 1-position of a monosaccharide, usually glu-... 

Natural antioxidante are present in foods as their endogenous constituents or are added to them to preserve their quality. Antioxidants that occur naturally in plant foods belong to e phenolic group of compounds and include phenolic acids, phenylpropanoids, flavonoids and isofiavones, including catechins and anthocyanins/anthocyanidins, as well as phytates, sterols and carotenoids, among others. In addition, vitamins C and E as well as phospholipids may act as antioxidants in foods. In oilseeds, phenolic antioxidmits are present in die fiee, esterified, glycosidic or bound form and may be simple or complex in their chemical stractures. 

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