Reactions of Psicose, Sorbose and Tagatose

Reactions of Psicose, Sorbose and Tagatose 1. Qualitative and Quantitative Testa 

Since the ketohexoses are easily converted into 5-hydroxymethyl-2-furaldehyde, a variety of qualitative colorimetric tests have been developed for the detection of this intermediate, using phenolic reagents. Although these tests have been applied to L-sorbose74-80 they would likewise be applicable to psicose and tagatose they merely serve, however, 

Chromatography has proved to be an excellent tool for the identification and isolation of carbohydrates. Both paper and partition chromatography were employed for the identification and separation of D-tagatose from the gum exudate of Sterculia setigera. Previous to that, D-psicose and L-sorbose had been placed in the absorption series listed for clay.88 Conditions for zoning keto-D-psicose pentaacetate on magnesol-celite have been described by Binkley and Wolfrom (see page 126, ref. 137). 

Definite identification of the crystalline ketohexoses could be made by x-ray diffraction methods. This was actually employed in the case of the isolation of D-tagatose from Sterculia setigera X-Ray crystallographic data for L-sorbose has been available for some time (see page 136, ref. 175). 

Since L-sorbose is a reducing sugar a number of methods for its determination, based on this property, have been reported. Titration with the ceric sulfate, potassium ferricyanide reagent showed a fructose to sorbose ratio of 1.1,86 Cupric citrate87 as well as cupric tartrate87 reagents appear to be equally useful. 

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