Does raffinose react with benedict's reagent?

Last Update: April 20, 2022

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Asked by: Orlando Koch
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The Benedict's reagent, which is a blue solution, is reduced to a red precipitate. If the aldehyde and ketone functional groups remain tied up in a glycosidic bond

glycosidic bond
A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate.
https://en.wikipedia.org › wiki › Glycosidic_bond
(as shown in the structure of raffinose), then they cannot react with the Benedict's reagent.

What does Benedict's reagent react with?

One test for the presence of many simple carbohydrates is to use Benedict's reagent. It turns from turquoise to yellow or orange when it reacts with reducing sugars. These are simple carbohydrates with unbound aldehyde or ketone groups.

What does not react with Benedict's reagent?

The products of sucrose decomposition are glucose and fructose, both of which can be detected by Benedict's reagent as described above. Starches do not react or react very poorly with Benedict's reagent due to the relatively small number of reducing sugar moieties which occur only at the ends of carbohydrate chains.

Is raffinose a reducing sugar or a non-reducing sugar?

This trisaccharide is very common in plant seeds, leaves, stems, and roots. As is evident from its structure (its anomeric carbon atoms are involved in glycosidic bonds), it is a non-reducing sugar.

Does Benedict's solution react with alcohols?

Reducing sugars have a free carbonyl group, either ketone or aldehyde. So, Benedict's test is used for the detection of ketone or aldehyde. ... It has an alcohol functional group so, ethanol cannot give a positive test for Benedict's test. Therefore, ethanol will not cause positive color change in Benedict's test.

Benedict's test- for reducing sugars

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What Colour is Benedict's solution?

Benedict's solution is blue but, if simple carbohydrates are present, it will change colour – green/yellow if the amount is low and red if it is high. A precipitate will also form if the sugars are present and the quantity of this gives an indication as to the quantity of sugars in the test sample.

Which sugar gives positive Benedict's test?

The reducing sugars that show positive results with benedict's solution are glucose, fructose, maltose etc. The correct option is D i.e. sucrose. Additional Information: Sucrose is a disaccharide composed of two monosaccharide molecules that are glucose and fructose.

What are examples of non reducing sugars?

> Non reducing sugars - A non-reducing sugar has no free carbonyl groups. They are in acetal or ketal form. These sugars do not show mutarotation. Common examples for these are Sucrose, raffinose, gentianose and all polysaccharides.

What makes a sugar reducing?

A reducing sugar is one that reduces another compound and is itself oxidized; that is, the carbonyl carbon of the sugar is oxidized to a carboxyl group. A sugar is classified as a reducing sugar only if it has an open-chain form with an aldehyde group or a free hemiacetal group.

What is Anomer example?

Anomers are cyclic monosaccharides or glycosides that are epimers, differing from each other in the configuration of C-1 if they are aldoses or in the configuration at C-2 if they are ketoses. ... Example 1: α-D-Glucopyranose and β-D-glucopyranose are anomers.

Why do all monosaccharides react with Benedict's reagent?

All monosaccharides are reducing sugars. ... If the reactive aldehyde or ketone groups of both monosaccharides are involved in the bond holding the two units together, these groups are not free to react with the copper ions in the Benedict's solution, and the disaccharide formed is not a reducing sugar.

What is the principle of Benedict Test?

When Benedict's solution and simple carbohydrates are heated, the solution changes to orange red/ brick red. This reaction is caused by the reducing property of simple carbohydrates. The copper (II) ions in the Benedict's solution are reduced to Copper (I) ions, which causes the color change.

How does Benedict's reagent work?

The principle of Benedict's test is that when reducing sugars are heated in the presence of an alkali they get converted to powerful reducing species known as enediols. When Benedict's reagent solution and reducing sugars are heated together, the solution changes its colour to orange-red/ brick red.

Is glycogen a reducing sugar?

c) Glycogen. No, it is a polysaccharide and like other polysaccharides it is a non reducing sugar. It occurs mainly in liver wet and muscle. Sugar is a type of carbohydrate.

What is Benedict's reagent formula?

One litre of Benedict's reagent can be prepared by mixing 17.3 grams of copper sulfate pentahydrate (CuSO4. 5H2O), 100 grams of sodium carbonate (Na2CO3), and 173 grams of sodium citrate in distilled water (required quantity).

Why is glucose positive in Benedict's test?

As we've seen, glucose is in equilibrium with an open-chain (or “linear”) form containing an aldehyde. ... This means that glucose will give a positive test with Benedicts' reagent, Fehlings solution, or the Tollens test, and the aldehyde will be oxidized to a carboxylic acid.

Why Ketoses are reducing sugars?

A ketose is a monosaccharide containing one ketone group per molecule. ... All monosaccharide ketoses are reducing sugars, because they can tautomerize into aldoses via an enediol intermediate, and the resulting aldehyde group can be oxidised, for example in the Tollens' test or Benedict's test.

Is starch reducing sugar?

Is starch a reducing sugar? It should be remembered here that starch is a non-reducing sugar as it does not have any reducing group present.

Why maltose is reducing sugar?

Maltose undergoes mutarotation at its hemiacetal anomeric center. Recall that the process occurs via an open-chain structure containing an aldehyde. The free aldehyde formed by ring opening can react with Fehling's solution, so maltose is a reducing sugar.

What is meant by reducing sugar and non-reducing sugar?

Reducing sugars are sugars where the anomeric carbon has an OH group attached that can reduce other compounds. Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds. ... Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar.

Is cellulose reducing or nonreducing sugar?

Also, Polysaccharides are all non-reducing, as none have the free Aldehyde or Hemiacetal group. So, yes Starch,Cellulose, Glycogen are non-reducing sugars. However, Polysaccharides arent considered as SUGARS(as per NCERT-XII).

Are Ketoses reducing sugars?

Both aldoses and ketoses are reducing sugars. Stronger oxidizing agents can oxidize other hydroxyl groups of aldoses. For example, dilute nitric acid oxidizes both the aldehyde group and the primary alcohol of aldoses to give aldaric acids.

Which sugar does not answer Benedict's test?

Sucrose contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, or the fructose to α-hydroxy-ketone form. Sucrose is thus a non-reducing sugar, which does not react with Benedict's reagent.

Why are there 8 drops of urine in Benedict's test?

For detection of sugar in Urine: Add 5 ml of Benedict's qualitative reagent in a test tube. Add 8 drops (0.5 ml) of urine. ... The contents of the tube becomes turbid due to a precipitate, which may range from green to brick red in colour, depending on the amount of sugar present in the urine.

How do you do a Benedict's test for reducing sugars?

Benedict's test for reducing sugars
  1. Place two spatulas of the food sample into a test tube or 1 cm 3 if the sample is liquid. ...
  2. Add an equal volume of Benedict's solution and mix.
  3. Place the tube in a water bath at about 95°C for a few minutes.
  4. Record the colour of the solution.