Cereal germ oils

The lipid content of total cereal seeds varies considerably. Furthermore the various anatomical parts of seeds contain a very different lipid content. Thus, in wheat seeds the germ contains 25-30% lipid while the endosperm has only 1% lipid. Considerable amounts of wheat germ lipid are lost during milling (Galliard and Barnes, 1980). Cereal germ oils are also a very good source of tocopherols. 

Steroids (e.g., - diosgenin [512-004-9] from - Dioscoreaceae, - stigmasterol [83-43-7] from - soybean oil, (3-sitosterol [83-46-5] from - wheat germ oil, ->soy bean oil, other cereal germ oils and sugarcane wax, and - cholesterol [57-88-5] from wool grease, distillation residues of animal fatty acids, spinal cord and brain are valuable raw materials for the synthesis of steroid intermediates. 

Weller, C.L., Paulsen, M.R., and Mbuvi, S. 1989. Germ weight, germ oil content, and estimated oil yield for wet-milled yellow dent com as affected by moisture content at harvest and temperature of drying air. Cereal Chem. 66, 273-275. 

Vitamin E (a-tocopherol) is most abundantly available in wheat germ oil and in small quantities in cereals, nuts, spinach, and egg yolk. Deficiency of vitamin E normally does not occur. Large doses of vitamin E are used to reduce the toxicity of vitamin A. Prolonged use causes delay in wound healing but significant... 

Commercial plant germ oils are mainly obtained from cereal grains, such as corn, wheat, and rice. In most cases, the endosperm of the grain is the part of interest for the industrial use of cereals. Starch and proteins are the major components of the endosperm. Endosperm represents 75-85% of the grain and protects the embryo, which is also referred to as germ. 

Naturally occurring vitamin E comprises a series of compounds called tocopherols. Among the richest sources are cereal germs and most oilseeds. a-Tocopherol (molecular weight 430.7 daltons), which possesses the highest vitamin E activity, is a yellow oil, insoluble in water, but soluble in organic solvents. It is readily oxidized and, therefore, is also used as an antioxidant. A vitamin E deficiency disease has... 

All four tocopherols and tocotrienols, with the chemical structures given in Fig. 3.45, are found primarily in cereals (especially wheat germ oil), nuts and rapeseed oils. These redox-type lipids are of nutritional/physiological and analytical interest. As antioxidants (cf. 3.7.3.2.1), they prolong the shelf lives of many foods containing fat or oil. The significance of tocopherols such as vitamin E is outlined in 6.2.3. 

Section 3.8.3.1 and Table 6.7 provide data on the tocopherol content in some foods. The main sources are vegetable oils, particularly germ oils of cereals. 

Wheat germ is added to many kinds of foods, such as bread, cookies, cereals, and milkshakes. Wheat germ oil may be taken to restore nutrients lost in defatting the germs. 

Sources.—A rich source is the unsaponifiable fraction of wheat-germ oil other good natural sources are lettuce, watercress, and wheat preparations that include intact germ moderately good sources are entire cereals, molasses, cotton-seed oil and hemp-seed oil. Animal foodstuffe are poor in the vitamin, and it is absent from liver oils of fish. 

In recent years, the conversion of starch to fructose has become a very important commercial process. High-fructose corn syrup (HFCS) is approximately twice as sweet as sucrose. It is used in soft drinks, canned fruits, lactic acid beverages, juice, bread, ice cream, frozen candies, and so on. HFCS can be obtained from a variety of cereals and vegetables, such as corn, wheat, rice, potatoes, and cassava. Corn is the most important source of HFCS because of low costs and excellent utilities of its by-products, corn meal, oil, gluten, germ, and fiber. 

Rice Oryza sativd) is an important cereal with an annual production of over 500-800 million tons. To produce white rice, the hull is removed and the bran layer is abraded giving 8-10% of the rice grain. The bran contains the testa, cross cells, aleurone cells, part of the aleurone layer, and the germ and includes almost all of the oil of the rice coreopsis. Gopala Krishna (45) considers that there is a potential for over 5 million tons of rice bran oil per annum, but present production is only about 0.7 million tons and not all of this is of food grade. India (0.50 million tons), China (0.12 million tons), and Japan (0.08 million tons) are the major countries producing rice bran oil. 

E Whole grain cereals, wheat germ, vegetable oils, lettuce, sunflower seeds Male lOmg/d 15 IU Female 8 mg/d 12 IU Preg 10-12 mg/d... 

The hpid content of cereal grains varies with spedes. Wheat, barley, rye and rice contain 10 30 g/kg DM, sorghum 30-40 g/kg DM and maize and oats 40-60 g/kg DM.The embryo, or germ, contains more oil than the endosperm in wheat, for example, the embryo has 100-170 g/kg DM of oil, while the endosperm contains only 10-20 g/kg DM.The embryo of rice is exceptionally rich in oil, containing as much as 350 g/kg DM. Cereal oils are imsaturated, the main adds being linoleic and oleic because of this they tend to become rancid quickly and also produce a soft body fat in pigs and poultry. 

Amaranthus (family Amaranthaceae) The origin of various species of cultivated amaranths is not easy to trace because of the distribution of wild ancestors however, amaranths are now cultivated as pseudo-cereals in both the Old and New Worlds. The grain contains up to 18% protein and the germ of the grain and bran contain about 20% oil, which can be used as vegetable oil. Various food products from grain amaranths can be found in Indian markets. Grain amaranth products are also found in health shops in Europe and the USA. 

The lipids are preferentially stored in the germ which, in the case of com and wheat, serves as a source for oil production (cf. 14.3.2.2.4). Lipids are stored to a smaller extent in the aleurone layer. Cereal lipids do not differ significantly in their fatty acid composition (Table 15.31). Linoleic acid always predominates. Close attention has been given to wheat lipids since they greatly influence baking quality ttnd they have therefore been studied thoroughly. 

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