Sugars material, determination

Plant material fractionation. The detailed steps of isolation and separation of oligosaccharide fractions were described earlier [10]. Pectin was separated by boiling the cell walls in 0.5 M ammonium-oxalate buffer, pH 5.2 at 100 C for Ih. The dialyzed solution of pectin was hydrolyzed with 0.15M HCl for 3h at 100 C. Neutralized and desalted hydrolysate was loaded to the column (lx90cm) filled with biogel TSK HW-40 (Toyo Soda, Japan) equilibrated and eluted with 50mM sodium acetate (pH 5.2) at a rate of 0.3ml/min. In all fractions (1ml) the sugars were determined by o-toluidine method (Resnikov et al., 1982) and fraction IP was collected as shown on Figure 1. 

Insoluble Matter. Insoluble matter in sugar is determined as the dry weight of material left on a filter or membrane after passage of a sugar solution. This may include bits of sand, filtration medium, plant material, and polymeric material. 

The 3rields of aldonic and oxalic acids are shown in Table XI. They are based on the amount of sugar oxidized (determined by reducing value) and not on the total amount of starting material. The formation of L-arabonic acid occurs with the highest percentage yield, but even this is low compared with other methods of preparation. As the lactobionic acid was isolated as the calcium lactobionate-calcium bromide salt, the actual amount of product, expressed in millimoles, is very low. 

Analysis.—The analysis of sugar is carried on, almost entirely, by the use of the polariscope. As sucrose has a definite optical rotation the determination of the rotation of a sugar solution gives us a means of accurately determining the amount of pure sucrose in any sugar solution or sugar material. 

The enzymatic convertibility of the solid fraction after pretreatment was determined for the pretreated materials as well as for the untreated maize silage. The enzymatic hydrolysis was carried out at 50 °C, pH 4.8, with 2% DM and an enzyme load of 30 FPU/g DM. The enzyme used was Cellubiix L (Novozymes, Denmark) and the amounts of hydrolyzed sugars were determined by high-performance liquid chromatography (HPLC see Analysis... 

Sugar Analyses. Hydrolyses of polysaccharide fractions and cell trail preparations were performed (a) directly with trlfluoroacetic acid ( ) and (b) after digestion with 72% sulfuric acid and dilution, with M-sulfuric acid (O. Allose was added as an Internal standard and the sugar mixtures were converted Into alditol acetates (12) for analysis by glc on column (a). Uronlc acid determlnaclons were carried out spectrophotometrlcally with the 3-hydro3qrdlphenyl reagent ( ). In the case of Insoluble materials determinations were performed after digestion with 72% sulfuric acid and appropriate dilution. 

Sixteen solid-phase materials were tested on a laboratory scale and the antho-cyanin and sugar content of collected fractions were determined. Among these, reverse-phase silica gels and macroreticular non-ionic acrylic polymer adsorbents such as Serdolit PAD IV or Amberlite XAD-7 turned out to be most suitable. SPE was used to investigate these materials on an enlarged scale, improving elution gradient and column purification. Amberlite XAD-7 was successfully applied in a middle-scale separation. ... 

There are numerous other compounds which can be determined in human body fluids. For some classes of compounds, e.g. nitrogen compounds, hormones, and sugars, a few reference materials are available. 

Matrix Components The term matrix component refers to the constituents in the material aside from those being determined, which are denoted as analyte. Clearly, what is a matrix component to one analyst may be an analyte to another. Thus, in one hand for the case of analyses for elemental content, components such as dietary fibre, ash, protein, fat, and carbohydrate are classified as matrix components and are used to define the nature of the material. On the other hand, reference values are required to monitor the quality of determinations of these nutritionally significant matrix components. Hence, there is a challenging immediate need for certified values for dietary fibre, ash, protein, fat, and carbohydrate. Concomitantly, these values must be accompanied by scientifically sound definitions (e.g. total soluble dietary fibre, total sulpha-ted ash, total unsaturated fat, polyunsaturated fat, individual lipids, simple sugars, and complex carbohydrates). 

Potter and co-workers 301) determined reducing sugars in plant materials by reducing copper(II) in alkaline solution to insoluble cuprous oxide and then measuring the excess copper in the filtrate. Mitschell248) conducted further studies on this method. Christian and Feldman 19) have described general procedures for the indirect determination of glucose and of protein. It is anticipated that in the future, we will see many more applications of atomic absorption spectroscopy to the indirect determination of nonmetals. 

Finally, when L-sorbose (81) was treated with hydrogen cyanide, a branched-chain, sugar lactone was formed which was characterized by converting it into a diacetal.127 An X-ray structure determination of this material revealed it to be 2,21 5,6-di-0-isopropylidene-[2-C-(hy-droxymethyl)-L-gulono-l,4-lactone] (82). However, all subsequent efforts to prepare 82 resulted in the formation of 2,3 5,6-di-0-isopropyli-dene-2-C-(hydroxymethyl)-L-gulono-l,4-lactone (83). 

Temperature. In most cases, the solubility of the material which is being extracted will increase with temperature to give a higher rate of extraction. Further, the diffusion coefficient will be expected to increase with rise in temperature and this will also improve the rate of extraction. In some cases, the upper limit of temperature is determined by secondary considerations, such as, for example, the necessity to avoid enzyme action during the extraction of sugar. 

Glyceraldehyde (2,3-dihydroxypropanal), acetol, and dihydroxyace-tone form 1-5% of biacetyl and a number of other products, including pyrocatechol and 33, after exposure to aqueous alkali at 300°. Such trioses as glyceraldehyde and dihydroxyacetone have been shown to form various hexoses by aldol reaction. Aldolization, followed by retro-aldoliza-tion, is undoubtedly a major consideration when three-, four-, and five-carbon sugars are subjected to elevated temperatures. Differences in thermolysis products, partially quantitative, are noticeable at 100°, but, at temperatures near 300°, it is quite difficult, if not impossible, to determine if the starting material was a triose, a tetrose, or a pentose. 

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