Corn sterol

Major flaxseed sterols are stigmasterol, camp sterol, and 5-5 avenasterol (Daun et al., 2003). Obtusifoliol, gramisterol, and citrostadienol constituted 45%, 22%, and 12%, respectively, of the total 4a-monomethylsterol in flaxseed (Kamm et al., 2001). Squalene content of flaxseed oil was reported as 4 mg/100 g oil, which was significantly lower than olive, corn, and rice bran oils. Squalene content is an intermediate compound of biosynthesis of plant sterols, which may have protective effects on lipid quality. Squalene could act as a peroxy radical scavengers in high polyunsaturated fatty acid oil (Dessi et al., 2002). 

The use of a modified starch, corn starch sodium octenyl succinate derivative, for encapsulation of sea buckthorn kernel oil (containing polyunsaturated fatty acids, tocopherols, tocotrienols, plant sterols and carotenoids) by spray-drying was found to improve oil stability. Better protection was afforded when the starch encapsulant was stored in its glassy state (Partanen et al. 2002). Methylcellulose and hydroxymethy-oellulose in combination with soy lecithin enabled the production of 40% (W/W) fish oil powders with improved stability (Kolanowski et al. 2004). 

STEROLS Phytosterols are mostly associated with unrefined vegetable oils and exist as derivatives of phenolic acids (e.g., ferulic acid). Several studies are available on antioxidant activity of sterols and their derivatives from sources such as corn fiber, oats, and rice. These compounds can be obtained from the unsa-ponifiable fraction that is removed during vegetable oil refining. Triterpene alcohols and hydrocarbons (131), or sterols (Figure 20) from oats (132, 133), rice (134, 135),... 

Figure 20. Chemical structure of antioxidative sterols identified from (a) oats, and (b) rice and corn fiber.

Sterol HEAR CAN LLCAN HOCAN HOLLCAN SOY SUN Corn... 

Figure 1. Structures of the common sterols (phytosterols) In corn and their comparison with cholesterol, the main sterol In animals. Note that cholesterol has 27 carbons, campesterol has 28 carbons, and all of the other phytosterols shown have 29 carbons.

Sterols The total phytosterol content (free and esterified phytosterols) of corn germ oil is higher than in most of the other vegetable oUs (3, 70). Com germ oil contains about 1.1% (w/w) phytosterol esters (70). Sitosterol is the major sterol... 

Sterol Coconut Corn Cotton Seed Linseed Olive Pam Palm Kernel Peanut Rape Seed Rice Bran Saf- flower Sesame Shea Butter Soy Bean Sun flower Wheat Germ... 

The unsaponifiable matter of soy, corn, canola/rapeseed, sunflower, cottonseed, peanut, and palm ranges from 10-30%, and it is composed of 40% phytosterols and 15% tocopherols (199-202). The temperature, duration, quantity of skimming vapor, and the extent of vacuum used for deodorization are the parameters that greatly influence the quality and quantity of DOD. The low content of tocopherols and sterols in the DOD often requires a concentration step however, if the starting material is soybean, this is not an issue because of the high concentration of these compounds. 

Com oil is composed of fatty acid esters with glycerol, known commonly as triglycerides. Typical com oil produced in the USA contains five major fatty acids linoleic 58.9% oleic 25.8% palmitic 11.0% stearic 1.7% and linolenic 1.1%. Com grown outside the USA yields com oil with lower linoleic, higher oleic, and higher saturated fatty acid levels. Corn oil also contains small quantities of plant sterols. 

As also shown in Fig. 11, the administration of cholestyramine, surfomer or corn oil to experimental animals results in essentially no change in the level of ACAT activity even though all three of these dietary manipulations increase rates of sterol synthesis in the mucosal cells (Fig. 6). Presumably after treatment with these agents that either block the uptake of luminal cholesterol or increase the intracellular demand for sterol, the rate of synthesis increases and just compensates for the changing needs for intracellular sterol. If such compensation is nearly perfect, then the metabolically active pool of cholesterol on the microsomal membranes would remain constant, as would apparent ACAT activity measured in these membranes. 

Table 5.12 Typical distribution (%) of sterols and sterol esters in crude sunflower, soybean and corn oil...

Details of the tocopherol components are shown in Table 5.11 (Muller-Mulot 1976) and of the sterols and sterol esters in Table 5.12 (Popov et al. 1975). Values for other typical vegetable oils, such as soybean and corn, are included for comparison. Both soybean and corn oils have higher levels of y-and 8-tocopherol than sunflower oil. There is some difference between the sterol contents of the three oils, but the sterol ester content of com oil is much higher than in either sunflower or soybean oils. 

Wilson, T.A., DeSimone, A.P., Romano, C.A. and Nicolosi, R.J. (2000) Corn fiber oil lowers plasma cholesterol levels and increases cholesterol excretion greater than corn oil and similar to diets containing soy sterols and soy stands in hamsters. J. Nutr. Biochem., 11, 443 149. 

Worthington, R.E. and Hitchcock, H.L. (1984) A method for the separation of seed oil steryl esters and free sterols Application to peanut and corn oils. J. Am. Oil Chem. Soc., 61, 1085-1088. 

Olive oil is often illegally adulterated with other less expensive vegetable oils. Oils widely used for this purpose include olive pomace oil, corn oil, peanut oil, cottonseed oil, sunflower oil, soybean oil, and poppy seed oil. °° Among the varions chemical and physical methods employed toward the detection of the adulteration of olive oil by low-grade olive oils and seed oils are (a) Sterol analysis (presence of stigmasterol and 3-sitosterol), (b) alkane analysis (C27, C29, and C31), (c) wax and aliphatic alcohol analysis, (d) fatty acids/(with HPLC) trans fatty acid, and (e) Triacylglycerol. 

Corn oil contains approximately 1% of sterols, which is unusually high for a vegetable oil. The composition of the triterpene alcohols, methylsterols and sterols are given in Table 3.145-3.147. 

Add plasma in 70% ethanol (1.5 mL) to the column, and allow to flow at 0.25 mL/min (if necessary, apply back pressure via the Leur-lock syringe). Collect the flow through and combine with column wash of 1.5 mL of 70% ethanol in a 15 mL polypropylene centrifuge tube (Corning Inc. Amsterdam, The Netherlands). Steroids, oxy-sterols, and bile acid elute in this fraction (SPEl-Fr-1). Elute less polar oxysterols from the column... 

Seitz, L.M. (1989) Stanol and sterol esters of femlic and p-coumaric acids in wheat, corn, rye, and triticale. J. Agric. Food Chem. 37, 662-667. 

Corn oil, Sterols and a-, 5-, and Saponification (ascorbic acid with GC-FID HP-5MS 0-200 pg with values of Du and Ahn... 

Small amounts of sitostanol and campestanol, which are 5,6-saturated analogues of the main 4-desmethyl sterols (sitosterol and campesterol), occur in plant materials such as coniferous trees (pine, spruce) and certain grains (rye, wheat and corn/maize). 

Table 6. Levels of sterols in crude corn oils as a percentage of total sterols (the values represent free and esterified phytosterols, measured after saponification)...

Jain D, Ebine N, Jia X, et at. 2008. Corn Fiber Oil and Sitostanol Decrease Cholesterol Absorption Independently of Intestinal Sterol Transporters in Hamsters. The Journal of Nutritional Biochemistry 19(4) 229-236. 

---