Wheat quantitation

Comparisons of yields of total headspace volatiles from vegetative tissues of tobacco and wheat Quantitative estimates of headspace total volatile yields are summarized in Table II. 

Wheat samples are extracted with dilute ammonia on the ASE200. The extracts are amended with isotopically labeled internal standards. The extracts are purified by sequential octadecyl reversed-phase solid-phase extraction (Cig SPE) and ethylenediamine-iV-propyl anion exchange (PSA) SPE. The samples are analyzed by LC/MS/MS. This method determines crop residues of flucarbazone-sodium and A-desmethyl flucarbazone with a limit of quantitation (LOQ) of 0.01 mgkg for each analyte. 

Early rhizosphere establishment is demonstrated in 2-3 day-old wheat plants when there is a shift towards a population of amino acid requiring bacteria (19). Maximum activity and numbers of rhizosphere microorganisms correlated with maximum vegetative plant development (20-22). Once established, the rhizosphere remains qualitatively similar, but quantitatively increases from seedling stage to maturity (23). After maturity the bacterial population reverts to a population similar to that in non-rhizospheric soils. 

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. 

J Pharmacol Exp Ther 184 506-514, 1973 Thompson JW, Weiner RD, Myers CP Use of ECT in the United States in 1975, 1980, and 1986. Am J Psychiatry 151 1657-1661, 1994 Thoren P, Asberg M, Gronholm B, et al CMI treatment of OCD. A controlled clinical trial. Arch Gen Psychiatry 37 1281-85, 1980 Thorne RG, Perfetti PA, Emory CR, et al Quantitative assessment of transneuronal transport to the rat olfactory bulb following intranasal administration of wheat germ agglutinin-horseradish peroxidase. Neurobiol Aging 13 (suppl 1) 132-133, 1992... 

Fluoropyruvate is converted quantitatively by pyruvate decarboxylase from wheat germ into acetate, fluoride (F ), and carbon dioxide. Propose a reaction mechanism. See Gish, G., Smyth, T., and Kluger, R. (1988) /. Am. Chem. Soc. 110, 6230-6234. 

The protocol developed by Holm et al. (1986) was evaluated by analysis of starch content in wheat starch, white wheat flour, whole-grain wheat, and industrially processed wheat products. The major advantage of this protocol over the Basic Protocol is its reduced cost. The chemicals for the reagent preparations and the enzymes are purchased directly from the companies that produce them. The original method did not include RS3 (resistant starch) in its quantitation. A DMSO treatment step has been added (step 4) to solve this problem. 

Schieberle, P. and Grosch, W. 1987. Quantitative analysis of aroma compounds in wheat and rye bread crusts using stable isotope dilution assay. J. Agric. Food Chem. 35 252-257. 

T Kuninori, J Nishiyama. Separation and quantitation of ferulic acid and tyrosine in wheat seeds (Triticum Aestivum) by reversed-phase high-performance liquid chromatography. J Chromatogr 362 255-262, 1986. 

In an headspace extract of fresh rye bread crust, 3-methylbutanal, (E)-2-nonenal and methional showed the highest FD-factors (Table 4), while 2-acetyl-1-pyrroline, the key odorant of wheat bread crust (cf. Table 3), did not significantly contribute to the rye (rust flavor. Quantitative measurements established [45, 55] that especially the higher odor activity (cf. 3, this chapter) of the boiled potato-like smelling methional in the rye bread crust in combination with the much lower odor activity of the roasty-smelling 2-acetyl-l-pyrroline mainly contribute to the overall flavor differences in rye and wheat bread crusts. 

The caramel-like smelling HDF has been established as a main contributor to the flavors of several processed foods (Table 17). In addition, it should be noted that in all these foods, on the basis of a high FD-factor, HDF was also by far the most important caramel-like smelling odorant. In the following, the strategy in the HDF precursor analysis will be shown using wheat bread crust, popcorn [88] and malt as the examples. Quantitative measurements were performed by using a stable isotope dilution assay (cf. Section 3.2.). 

Sun RC, Sun XF, Zhang SH. 2001. Quantitative determination of hydroxycinnamic acids in wheat, rice, rye, and barley straws, maize stems, oil palm frond liber, and fast-growing poplar wood. J Agric Food Chem 49 5122-5129. 

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