Fructose from oligosaccharides

As a typical acetal bond, a glycosidic bond readily hydrolyzes in an acid-catalyzed reaction. In this manner, di- and oligosaccharides can be split into monosaccharides. It is a common method for manufacturing of invert sugar, a mixture of a-D-glucose and P-D-fructose, from sucrose. 

Robinia pseudacacia resulted in accumulation of free fructose and oligosaccharides containing principally glucose residues. Transfructosidases have also been found in both plant nectar and insect viscera. A trans-glucosidase with specificity different from the other enzymes described occurs in honeydew and manna formed by certain insects. This enzyme is produced by the insects, not the plant, and transfers glucosyl groups to the 3-position of the fructose of sucrose. ... 

Polymers of D-fructose are important carbohydrate reserves in a number of plants. Inulins and levans are two major types that differ in structure. D-Fructans require only relatively mild conditions for their hydrolysis, for example, levan was qualitatively hydrolyzed by hot, dilute, aqueous oxalic acid. Permethylated fructans could be hydrolyzed with 2 M CF3CO2H for 30 min at 60°. Fructan oligosaccharides were hydrolyzed in dilute sulfuric acid (pH 2) at 70 (see Ref. 53) or 95° (0.1 M). D-Fructans from timothy haplocorm (where they comprise 63% of the water-soluble carbohydrates) could be hydrolyzed with 0.01 M hydrochloric acid at 98°. 

Bees collect the mannas or honeydews from these sources when nectar is not readily available, and process it to a product which, as already mentioned, is darker in color, lower in D-glucose and D-fructose, and higher in pH, oligosaccharides, total free acid, ash, and nitrogen than the original honeydew. 

Reduction. Mono- and oligosaccharides can be reduced to polyols (polyhydroxy alcohols) termed alditols (glycitols) (1) (see Sugaralcohols). Common examples of compounds in this class are D-glucitol (sorbitol) [50-70-4] made by reduction of D-glucose and xyhtol [87-99-0] made from D-xylose. Glycerol [56-87-5] is also an alditol. Reduction of D-fructose produces a mixture of D-glucitol and D-mannitol [69-65-8]. 

Many of the same conclusions may be drawn from results with synthetic auxins as from indole-3-acetic acid water intake increased, there was a lessening of the downward translocation of photosynthate with temporary increases of soluble carbohydrates in the leaves, and alterations appeared in the metabolic ratq and direction and in enzyme activity. However, the direct site of action is not known, and many of the effects are puzzling. n-Fructose oligosaccharides in artichoke and chicory storage-tissue were diminished by 70% (calculated on the content of dry matter) in 6 days... 

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