Traditional and Emerging Feedstocks for Food and Industrial Bioproduct Manufacturing - Food and Industrial Bioproducts and Bioprocessing - page 4

Proteins are the second largest group of compounds in endosperm (12-15%). Cereal
proteins are classified based on their solubility characteristics; water soluble albumins
(5-10%), dilute salt-solution soluble globulins (5-10%), aqueous alcohol soluble prolamins
(40-50%) and dilute acid or alkali soluble glutelins (30-40%) (Godon, 1994). Cereal
proteins, similar to other plant proteins, are low in some of the essential amino acids, for
example lysine. Glutamic acid is the major amino acid in wheat.
Lipids are the minor components of wheat grain (2-3%) and consist of polar and nonpolar
components. Triacylglycerides (TAG) make up majority of the nonpolar lipids that are rich
in unsaturated fatty acids. Huge variations in linoleic acid content of wheat, 45-75% of total
fatty acids, were reported among five market classes of wheat (Davis et al ., 1980 ). Polar
lipids include glycolipids and phospholipids (Godon, 1994).
The mineral content of wheat grain varies between 1 and 3%. Even though the mineral
content is not very high, wheat could provide significant amount of minerals as it is readily
found in most daily diets. Magnesium, phosphorous and potassium are the most abundant
minerals. Phosphorous is mostly present in the organic form phytic acid. It has been reported
that agronomic condition does not have a significant effect on the mineral composition of
wheat grain (Godon, 1994). Wheat grain is rich in vitamins, niacin (about 6 mg/100 mg) and
tocopherols (about 20 mg/100 g) (vitamin E).
Wheat bran and germ fractions are rich sources of a number of phytonutrients, including
policosanol (PC), phytosterols (PS),

-tocopherol and phenolic acids. A number of studies
have shown that PS and PC reduce serum low density lipoprotein (LDL) cholesterol levels
(Ostlund, 2002; Hirai et al ., 1984 ; Quilez et al ., 2003 ; Aleman et al ., 1994 ; Castano et al .,
2000; Gouni-Berthold and Berthold, 2002). Antioxidant properties of wheat bran and germ
extracts are well known (Zhou et al ., 2004). It has been reported that dietary wheat bran
provides protection against colorectal cancer (Qu et al ., 2005). This property is due to the
presence of phenolic acids, lignans and flavonoids in wheat bran. Wheat germ contains
approximately 11% oil (Dunford and Zhang, 2003; Eisenmenger and Dunford, 2008; Dunford,
2005). The oil contains a number of bioactive compounds, such as tocopherols (Eisenmenger
and Dunford, 2008; Dunford and Zhang, 2003), polyunsaturated fatty acids, PS (Chen et al .,
2009a ), and PC (Chen et al ., 2009b ; Irmak and Dunford, 2005 ; Irmak et al ., 2005 ). Wheat
germ oil (WGO) is the richest natural source of vitamin E (Kahlon, 1989). It has been reported
that wheat germ oil improves human physical fitness; this effect is attributed to its high PC
content (Cureton, 1972). There are numerous research studies indicating that 5-20 mg/day of
PC consumption is effective in lowering total cholesterol (17-21% reduction) and low density
lipoprotein (21-29% reduction) levels and increasing high density lipoprotein (HDL) (8-15%
increase) by inhibiting cholesterol synthesis and increasing LDL processing (Menendez et al .,
1994, 1999). There is scientific evidence that PC has additional beneficial effects on smooth
muscle cell proliferation, platelet aggregation and LDL peroxidation (Taylor et al ., 2003 ). PC
formulations are being used as “antifatigue drugs” (Cureton, 1972). Currently, beeswax and
sugar cane are the main sources of PC. It is important to note that there have been reports
indicating that the cholesterol lowering properties of PC are not reproducible in studies
performed in United States (Varady et al ., 2003). A better understanding of the effects of PC
on disease prevention and treatment requires large scale independent animal and clinical
studies involving various ethnic groups and subjects with different health histories.
Wheat straw is a lignocellulosic material containing about 35-40% cellulose, 30-35%
hemicellulose and 10-15% lignin (Harper and Lynch, 1981). Wheat straw also contains both
lipophilic and hydrophilic extractives, which may be released and/or interfere during pulping
and pretreatment of feedstock prior to hydrolysis of carbohydrate polymers to their monomeric

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