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Chemistry LibreTexts

Reducing Sugar

  • Page ID
    42311
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    A reducing sugar is a carbohydrate that is oxidized by a weak oxidizing agent (an oxidizing agent capable of oxidizing aldehydes but not alcohols, such as the Tollen’s reagent) in basic aqueous solution. The characteristic property of reducing sugars is that, in aqueous medium, they generate one or more compounds containing an aldehyde group.

    eg. 1: α-D-glucose, which contains a hemiacetal group and, therefore, reacts with water to give an open-chain form containing an aldehyde group.

    reducingsugar1.png

    eg. 2: β-D-glucose, which contains a hemiacetal group and, therefore, reacts with water to give an open-chain form containing an aldehyde group.

    reducingsugar2.png

    eg. 3: α-D-fructose, which contains a hemiketal group and, therefore, reacts with water to generate an open-chain form, which, in basic medium, is converted to compounds containing an aldehyde group.

    reducingsugar3.pngreducingsugar4.png

    eg. 4: maltose, which contains a hemiacetal group and, therefore, reacts with water to generate an open-chain form containing an aldehyde group.

    reducingsugar5.png

    see also nonreducing sugar


    This page titled Reducing Sugar is shared under a All Rights Reserved (used with permission) license and was authored, remixed, and/or curated by Gamini Gunawardena via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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