Question
Describe how to carry out the test for reducing sugars. Keywords:Benedict's, heat colour change, blue red. 1. __ 2. 3. __ __ __ __ __ 4. wh
Answer
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Jena
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Answer
1. Dissolve some of the test substance in distilled water to make a sample solution.2. Add approximately 2 cm³ of Benedict's Reagent to the sample.3. Heat the mixed solution in a gently boiling water bath for about 5 minutes.4. Observe the colour change; if it changes from blue to green/yellow/orange/red then a reducing sugar is present, if it stays blue no reducing sugar is detected.
Explanation
Benedict's Bisulfite is commonly used in a test called the Benedict's test, which tests for the presence of reducing sugars. Reducing sugars are mono and disaccharides that have the ability to reduce other compounds and therefore act as reducing agents.1. Reducing sugars include all monosaccharides, such as glucose and fructose, and some disaccharides like maltose.2. Through the Benedict's test we can check for the presence of these sugar types. Here's how we can carry out the test: a. We first prepare a sample solution by dissolving some of the substance in distilled water. b. We add a bunch of Benedict's reagent, which is a blue solution, to the sample solution. About 2 cm cubed can be enough. c. We heat the ingredients in a gently boiling water bath for about 5 minutes. d. Positive results are indicated by a color change from blue to green, yellow, orange, brown and finally, red depending upon the sugar concentration. Hence, if the sugar is present in large amounts, brick red insoluble copper (І) oxide will be formed. e. Conversely, if the mixture remains blue (the original color of the Benedict's solution) then this indicates a negative result: that is, no reducing sugars have been detected.3. It's important to understand that the colours are only indicative - the specific proportions of sugar and water, heating time etc., can all have an effect on the exact colour. But always, a colour change from blue inducting copper(II) compunds to a precipitate from green to red indicating predominantly copper(I) compound signifies the reduction.