Difference Between Reducing Sugar and Nonreducing Sugar

Main Difference

The main difference between reducing sugar and nonreducing sugar is that the reducing sugar is the sugar that has its ability to reduce others or oxidize itself, whereas the non-reducing sugar is the sugar that has its ability to oxidize others and reduce itself.

Reducing Sugar vs. Nonreducing Sugar

Reducing sugar is the type of sugar that has free functional groups such as aldehyde group and ketone groups, whereas the nonreducing sugar is the type of that has no free functional groups such as aldehyde group and a ketone group. Reducing sugar has its ability to reduce others and oxidize itself, while nonreducing sugars have its ability to oxidize others and reduce itself. Reducing sugars also have an ability to reduce Fehling’s solution and Tollens test; on the other hand, nonreducing sugars do not have the ability to reduce Fehling’s solution and Tollens test.

Reducing sugar has the ability to reduce the cupric ions into cuprous ions in Benedict’s solution, on the contrary, nonreducing sugar does not have the ability to reduce the cupric ions into cuprous ions in Benedict’s solution. The absence and presence of reducing sugar can be identified with the help of different kinds of tests on the flip side, the absence or presence of nonreducing sugar cannot be identified with the help of any test.

Reducing sugar is usually sweet, whereas the nonreducing sugar is not sweet. Reducing sugar can or cannot be hydrolyzed, whereas the nonreducing sugar can easily be hydrolyzed. Reducing sugar has low molecular weight, whereas the nonreducing sugar has a high molecular weight.

Comparison Chart

Reducing SugarNonreducing Sugar
The reducing sugar is the sugar that can reduce others or oxidize itself.The non-reducing sugar is the sugar that can oxidize others and reduce itself.
Reducing Agent
Best reducing agentsBad reducing agent
Chemical Properties
Have free ketone or aldehyde groupDo not have any free aldehyde or ketone group
Tests
Can be identified by testsCannot be identified by tests
Taste
Sweet tasteBad taste
Hydrolysis
Can or cannot hydrolyzeCan be hydrolyzed
Molecular Weight
Low molecular weightHigh molecular weight
Solubility
Soluble in waterInsoluble in water
Example
Monosaccharides and some disaccharidesSome disaccharides and polysaccharides

What is Reducing Sugar?

Reducing sugar is the kind of sugar that has an aptitude to reduce others and oxidize itself in a chemical reaction. Reducing sugar is the best known as reducing agents. It can reduce the cupric ions into the cuprous ions of a Fehling’s and Benedict’s solutions or tests. Reducing sugar can be recognized by the different kinds of oxidizing agents also.

The reducing agent has some good chemical properties. Reducing agents of reducing sugar has some free functional groups such as ketonic groups or aldehyde groups that are involved in determining the unique properties of reducing sugar. Reducing sugar has a sweet, sugary, and saccharine taste. Reducing sugar not always can be hydrolyzed.

On hydrolysis, reducing sugar gives some monosaccharides, such as some disaccharides. The molecular weight of reducing sugar is very low. Reducing sugar is also some soluble in water. All the reducing sugars are included in carbohydrates. Reducing sugars are the sugars that can be oxidized even with the help of week oxidizing agents.

Examples of reducing sugars are monosaccharides such as glucose, fructose, ribose, and ribulose, and some disaccharides such as lactose and maltose are included in reducing sugars.

What is Nonreducing Sugar?

Nonreducing sugar is the kind of sugar that has an aptitude to oxidize others and reduce itself in a chemical reaction. Nonreducing sugar is the worst known as the reducing agents. It cannot reduce the cupric ions into cuprous ions of a Fehling’s and Benedict’s solutions or tests. It can be recognized by different kinds of reducing agents also.

Reducing sugar does not have some good chemical properties. Nonreducing sugar does not have any free functional groups such as ketonic groups and aldehyde groups. These characteristics give extra unique characteristics to the nonreducing sugars. Nonreducing sugars also do not have any sweet or saccharide taste.

Nonreducing sugar can easily be hydrolyzed. On hydrolysis, it yields some monosaccharides and some disaccharides. Nonreducing sugar has a very high molecular weight. It is insoluble in water. All the nonreducing sugars are included in carbohydrates. Nonreducing cannot oxidize with the help of week oxidizing agents.

Examples of nonreducing sugars are some disaccharides such as sucrose and polysaccharides such as starch, glycogen, and cellulose, etc.

Key Differences

  1. Reducing sugar has functional groups such as aldehyde group and ketone groups, whereas the nonreducing sugar does not have any free functional groups such as aldehyde group and a ketone group.
  2. Reducing sugar can concentrate others and oxidize itself while nonreducing sugars can oxidize others and reduce itself.
  3. Reducing sugars also can reduce Fehling’s solution and Tollens test; on the other hand, nonreducing sugars cannot reduce Fehling’s solution and Tollens test.
  4. Reducing sugar can lessen the cupric ions into cuprous ions in Benedict’s solution; on the contrary, nonreducing sugar cannot lessen the cupric ions into cuprous ions in Benedict’s solution.
  5. The lack and occurrence of reducing sugar can be identified by different tests; on the flip side, the lack or presence of nonreducing sugar cannot be identified by different tests.
  6. Reducing sugar has a sweet taste, whereas the nonreducing sugar has a less sweet taste.
  7. Reducing sugar may or may not hydrolyze, whereas the nonreducing sugar can be hydrolyzed.
  8. The molecular weight of reducing sugar is very low, whereas the molecular weight of nonreducing sugar is high.

Conclusion

The above discussion concludes that reducing sugar is different from nonreducing sugar chemically. Reducing sugar is the sugar that has free functional groups such as aldehyde or ketonic groups, while nonreducing sugar is the sugar that does not has any free functional groups such as aldehyde or ketonic group.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss

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