Reducing sugar

About: Reducing sugar is a research topic. Over the lifetime, 1510 publications have been published within this topic receiving 47722 citations.

[7] Chemical procedures for analysis of polysaccharides

Abstract: Publisher Summary This chapter presents a procedure for the determination of glycogen and starch. Determination of glycogen by the modified Pfluger method consist digestion of the tissue in hot concentrated KOH, precipitation of the glycogen with ethanol, hydrolysis of the glycogen with acid, and determination of the glucose in the hydrolyzate as reducing sugar. Determination of glycogen with anthrone reagent includes digestion with 30% KOH. The glycogen is treated with the anthrone reagent and determined colorimetrically as glucose. Determination of glycogen in tissues of low glycogen content include digestion by boiling water and 1.25 ml. of 95 % ethanol is added for centrifugation. The glycogen is hydrolyzed by the addition of 1 ml. of 0.6 N HC1 for 20 minutes. The sugar is determined by any of the standard methods for microdetermination of sugars. The principle of determination of starch states that starch can be determined as glucose when extracted from dried plant tissue treated with perchloric acid, precipitated with iodine, and hydrolyzed with acids. Starch or glycogen determined by methylation technique.

Osmotic and Salt Stress-Induced Alteration in Soluble Carbohydrate Content in Wheat Seedlings

Abstract: The effect of drought and salt stresses on the water soluble carbohydrate content in wheat (Triticum aestivum L.) seedlings was examined to characterize the involvement of major sugar components in the adaptive processes. Hydroponically grown seedlings of four wheat varieties differing in drought and salt tolerance were exposed to consecutive water (polyethylene glycol, PEG) and salinity (NaCI) stresses. Total water-soluble carbohydrate (WSC), glucose, fructose, sucrose, and fructan content of stems (non-photosynthetic tissue) were determined. Tolerant genotypes accumulated more soluble carbohydrate than did sensitive ones. Both ionic and non-ionic stresses increased the concentration of reducing sugars, sucrose, and fructans. Drought tolerant varieties accumulated sucrose to a significantly greater level than did sensitive ones under non-ionic stress condition. Changes in fructan content of plants after transfer from PEG to NaCI containing solutions were genotype dependent, increasing in salt tolerant and decreasing in salt sensitive cultivars. These results indicate that WSC might be a useful marker for selecting genotypes that are more drought or salt tolerant. The type of sugar comprising the increase in WSC appears to be a less reliable marker since the initial response was an increase in monosaccharides and the delayed response was an increase in fructan.

The composition of reducing sugars in solution

Abstract: Publisher Summary This chapter discusses the composition of reducing sugars in solution. Reducing sugars differ from most other organic compounds in one characteristic property. When a pure organic compound that is not a reducing sugar is dissolved in a solvent, it is certain that the solution will usually contain only one compound; but when a reducing sugar, above an aldotetrose or a 2-pentulose, is dissolved in water, a solution is obtained that always contains at least six compounds: two pyranoses, two furanoses, and an acyclic (open-chain) carbonyl form and its hydrate. There are also minute proportions of septanoses and dimers. Very few of these many compounds that are present in the equilibrium solutions of sugars have ever been isolated. The only method for separating them from the equilibrium mixture is by crystallization and that depends on the fortuitous presence of seed crystals. The chapter details about the pyranose form, the furanose form, and the septanose form. It also discusses the composition of aldoses, ketoses, and substituted and derived sugars in aqueous solution.