Hull Cereals

Dehulling of rice, oats and barley requires special processes (cf. 15.1.4). 

Polished white rice is made from this cleaned rice by additional treatment of the kernels with talc (a magnesium silicate) and 50% glucose solution. This imparts a glossy, transparent coating to the kernels. 

White rice, in comparison to rough or brown rice, is low in vitamin content (cf. Table 15.38) and in minerals. A nutritionally improved product may be obtained by a parboiling process, orginally developed to facilitate seed coat removal. About 25% of the world s rice harvest is treated by the following process raw rice — steeping in 

Unlike in Europe and USA, some rice varieties popular in Asia develop a popcom-like aroma on cooking. This is due to the formation of 2-acetyl-1-pyrroline, which is present in concentrations of 550-750 pg/kg in aromatic varieties of rice (cooked) and 8 pg/kg in lowaroma varieties. 

Oat flakes are produced by the following processing steps the kernels (12-16% water content) are steamed and then the moisture content is decreased to 7-10% in 2-3 h by heating at 90-100 °C. The hull (fruit and seed coats) is removed, i. e., the kernel is polished. This is followed by repeated steaming, squeezing between drum rollers, and drying of the moist flakes till the water content is 10-11%. The yield is 55-65%. This hydrothermic process also inactivates the oat enzymes involved in offflavor development. (E,E,Z)-2,4,6-Nonadienal produces the cereal-like, sweet aroma of oat flakes. It has 

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Wolf WJ, Sessa DJ, Wu YV, Thompson AR 2(X)2. Air classification of pin milled soybean hulls. Cereal Chem 79(3) 439-444. 

Many plant products are very rich in cell wall materials. Cereal brans, seed hulls, various pulps (including beet pulp), citrus peels, apple pomace... are typical exemples of such by-products (1,2). They can be used after simple treatments as dietary fibres, functional fibres or bulking agents, depending on the nutritional claims (2). They can be used also eis sources of some polysaccharides. 

Zheng, G. H., Han, H. L., Bhatty, R. S. (1999). Functional properties of cross-linked and hydroxypropylation waxy hull-less barley starches. Cereal Chem., 76,182-188. 

Cereals contain also different HBAs. Canadian wheat flours were found to contain vanillic acid (up to 16 mg/kg) and syringic acid (up to 7 mg/kg). Oats contain vanillic acid, 4-HBA and salicylic acid, particularly in the hulls [6]. 

Zheng, G.H. and Bhatty, R.S. 1998. Enzyme-assisted wet separation of starch from other seed components of hull-less barley. Cereal Chem. 75 247-250. 

Malt sprouts are obtained from malted barley by the removal of the rootlets and sprouts which may include some of the malt hulls, other parts of malt and foreign material unavoidably present. The traded product must contain not less than 24% CP. The term malt sprouts, when applied to a corresponding portion of other malted cereals, must be in a qualified form i.e. Rye Malt Sprouts, Wheat Malt Sprouts, etc. Malt sprouts are also known as malt culms in some countries. IFN 5-00-545 Barley malt sprouts dehydrated IFN 5-04-048 Rye malt sprouts dehydrated IFN 5-29-796 Wheat malt sprouts dehydrated. 

As used in this Chapter, the term non-endospermic hemicellulose refers to hemicelluloses from aerial tissues and organs (bran, cob, hull, husk, leaves, stems, and other parts), but excludes those from root tissues. The hemicelluloses associated with cereal starches and flours are collectively termed endospermic hemicelluloses. 

Moreau, R.A. Flores, R. Hicks, K.B. 2007. The composition of functional lipids in hulled and hull-less barley in fractions obtained by scarification, and in barley oil. Cereal Chem. 84 1-5. 

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. 

The first oilseed application for extrusion was rice bran (99, 100). Really a cereal grain rather than an oilseed, rice seeds have a brown, paper-thin coating called rice bran that surrounds the starchy kernel. Once the hull is removed, the brown kernel is exposed. The bran is removed by polishing process that breaks up the bran into... 

In 1921, the QUAKER OATS COMPANY of Cedar Rapids, Iowa, had some redundant pressure cookers no longer needed for an abandoned cereal process. To make use of this equipment, and of massive quantities of oat hulls from their manufacture of rolled oats, they started an industrial production of furfural. 

This company never had a pilot plant for furfural. Work moved directly from the laboratory experiments to what was essentially a full scale unit. This was the result of the fact that the QUAKER OATS COMPANY had available in the plant at Cedar Rapids, where the first furfural processing plant was to be operated, a number of iron pressure cookers about 8x12 feet, which had been used in the manufacture of a cereal product which did not prove profitable. Since these cookers were available and since the process was to consist of the treatment of oat hulls with acid under pressure, it seemed advisable to try to use these digesters at least for the first attempts at large scale operation. 

Routes of exposure are oral, intravenous, and intramuscular. Dietary sources include cereal grains, the hull of rice, yeast, peas, beans, pork, and beef. 

Furfural. The commerdal production of furfural depends on the conversion of the pentosans of oat hulls and other cereal products. Using lose as an example, the hydrolytic reaction may be represented as follows ... 

The antioxidant activity of different food products has been linked to their preventive role in cardiovascular disease [68 86 98 99]. Many of them are fruit and vegetables, although cereals, herbs and spices also show important antioxidant activity. Processed fruit products also provide important antioxidant protection as has been described for orange and lemon juice, [100], grape juice [91], grape pomace [101] and red wines [102-107]. Very pronounced in vitro antioxidant activity has been demonstrated in tea [99 108] and olives [27]. Many herbs and spices containing antioxidant constituents can be useful to prevent rancidity of meat and fish products [109-112]. Fibre also has antioxidant activity, mainly due to the presence of phenolic metabolites linked to the polysaccharides [87]. Thus, the antioxidant activity of barley leaves [93], pineapple peel fibre [113] and rice-hull [114] have been described. 

Patterson, D.M. 1998. Malting oats effects of chemical composition of hull-less and hulled genotypes. Cereal Chem., 75, 230-234. 

Nuts, seeds, and grains are not considered as sources of organic acids. Other than amino acids and fatty acids, they contain phenolic acids and phytic acid. Phytic acid and its salts, phytats, are regarded as the primary storage form of both phosphate and inositol in seeds, mostly within the hulls. The phytic acid content of cereals (whole grain) varies from 0.5% to 2.0% [21],... 

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