Wheat separation methods

Analytical techniques for the quantitative determination of additives in polymers generally fall into two classes indirect (or destructive) and direct (or nondestructive). Destructive methods require an irreversible alteration to the sample so that the additive can be removed from the plastic material for subsequent detention. This chapter separates the additive wheat from the polymer chaff , and deals with sample preparation techniques for indirect analysis. 

Most of the applications of HPLC for protein analysis deal with the storage proteins in cereals (wheat, corn, rice, oat, barley) and beans (pea, soybeans). HPLC has proved useful for cultivar identihcation, protein separation, and characterization to detect adulterations (illegal addition of common wheat flour to durum wheat flour) [107]. Recently Losso et al. [146] have reported a rapid method for rice prolamin separation by perfusion chromatography on a RP POROS RH/2 column (UV detection at 230nm), sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), and molecular size determination by MALDl-MS. DuPont et al. [147] used a combination of RP-HPLC and SDS-PAGE to determine the composition of wheat flour proteins previously fractionated by sequential extraction. 

A method for determination of various types of peroxides consists of RP-HPLC separation and applying post-column UV radiation to convert the peroxide to H2O2, which may be determined by CLD with bis(2,4,6-trichlorophenyl) oxalate (140) in the presence of 2,4,6,8-tetrathiomorpholinopyrimido[5,4-(J]pyrimidine (194) as fluorescence enhancer. Dibenzoyl peroxide and f-butyl perbenzoate have LOD (SNR 3) 6.8 and 7.5 p.M, respectively, and linearity range from 40 to 400 p.M. The method was applied for determination of dibenzoyl peroxide used as whitener of wheat flour, after extraction with ethanol . See a similar method in Section VLB.3. 

Of the related polysaccharides mentioned earlier (see p. 267), only arabinoxylans have been examined in any detail by enzymic methods. Goldschmid and Perlin153 studied the fine structure of wheat arabinoxylan by using the /3-D-xylanase from Streptomyces QMB 814. Their results indicated that arabinoxylan molecules are mainly constituted of highly branched regions in which isolated and paired L-arabinosyl (A) branches are separated by single D-xylosyl (X) residues, as shown in 12, but that, at unequal intervals (averaging... 

Variations in the quality of bread depend essentially on the quality of the flour used, the method of preparation and the degree to which the baking is carried. Wheaten flour, which is that most commonly used for making bread, varies in composition according as the separation of the offals (bran, etc.) is more or less complete. Flour usually constitutes about 80% of the whole of the wheat, but bread may be made of wholemeal or even of meal containing an excess of bran. Other flours are also sometimes used for making bread, either alone or in admixture with wheaten flour. 

Camden, Australia An improved one-dimensional gel electrophoresis method was used to separate three waxy proteins in wheat starch 261... 

Application of LC/MS to Sulfonylurea Multiresidue Analysis in Wheat Grain. To test the applicability of this LC/MS method for residue analysis, we applied the method for the analysis of HARMONY, GLEAN and LONDAX in wheat grain. The objective was to determine the effect of the matrix on the separation and ion signal. Another objective was to determine the recovery using a ample extraction procedure with no sample clean up. 

Two approaches have been proposed to improve the electrophoretic separation between bone and liver ALPs. Both methods exploit differences in the carbohydrate portions of the two forms of ALP. In one, electrophoresis is carried out in the presence of wheat germ lectin, which retards bone ALP migration more than the liver enzyme migration. In the other, serum is treated briefly (i.e.> for 15 min at 37 °C), with neuraminidase to remove part of the terminal sialic acid residues. As the sialic acid residues of bone ALP are more readily attacked than those of liver ALP, the electrophoretic mobility of the bone form is reduced more than that of liver ALP. The improved separation allows quantitative estimates to be made by densitometric scanning (Figure 21-5). ... 

Despite the variety of sources, all lignocellulosic material is composed primarily of cellulose, hemicellulose and lignin [22], Agricultural wastes such as bagasse, com stover and wheat straw are thus a relatively cheap source of these three biopolymers. The major challenge to using lignocellulosic biomass as a feedstock is the development of cost-effective methods to separate, refine and transform it into chemicals and fuels [20],... 

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