What is a Maltose? Its Properties, Sources and Uses

Aug 11, 2022 | Team Turito



Carbohydrates are the basic components of food. They are composed of carbon, hydrogen, and oxygen. Lower molecular weight carbohydrates are generally known as sugars, and their name ends in the characteristic ‘ose’. Some examples of these sugars are sucrose, lactose, glucose, maltose, etc.

Maltose is a type of disaccharide sugar. It results from joining two glucose units with an α(1→4) bonding. The general formula for disaccharides is Cₙ(H₂O)ₙ₋₁. The molecular maltose formula is C12H22O11. It is a reducing sugar and undergoes mutarotation.

To know more about maltose, follow this article till the end.

History of Maltose

At the rise of the 19th century, when a shortage of cane sugar occurred, scientists started looking for other sugar sources. French chemist Augustin-Pierre Dubrunfaut first discovered it. Initially, his idea was not accepted by many chemists. But in 1872, Irish chemist and brewer Cornelius O’Sullivan proposed his experiments and confirmed the disaccharide maltose.

The word maltose is derived from ‘malt’, and as it is a sugar, the suffix ‘ose’ is added to it. Hence, it is named ‘maltose’ and also known as malt sugar or maltotriose. In China, the manufacturing of maltose has a record since the period of Emperor Jimmu, Shang Dynasty.

What is a Maltose?

Maltose is a disaccharide type of carbohydrate. It is devised from two molecules of glucose. With the removal of a water molecule, two glucose molecules form a bond. As a result, maltose is formed.

The malt sugar or maltose formula is C12H22O11.H2O. It is prepared from starch by diastase. On hydrolysis by acids, maltose gives only d-glucose.

While leaning dough, yeast provides the sugar content. Most of the sugar available to yeast is maltose, which is derived from starch. Maltose acts like an early product of photosynthesis rather than a storehouse product, for instance, starch and its deteriorated products.

Maltose Structure

The carbohydrates are usually divided into monosaccharides, oligosaccharides, disaccharides, and polysaccharides, depending on the number of sugar subunits. Maltose is a disaccharide-type carbohydrate. Therefore, what is maltose made of is two sugar units, an oligosaccharide and a disaccharide. It consists of two modules of glucose molecules. Glucose is an ordinary hexose, i.e., a monosaccharide containing six carbon atoms.

In maltose, the two units of glucose are in the pyranose form. An O-glycosidic bond joins these units. In such bonding, the first carbon (C1) of the first glucose molecule is linked to the 4th carbon (C4) of the second glucose molecule, resulting in (1→4) bond formation.

Because the glycosidic linkage to the anomeric carbon (C1) is in the opposite plane from the CH2OH substituent of the same glucose ring, the bonding is characterised as α. While if this glycosidic linkage takes place in the same plane, it would be expressed as a β(1→4) linkage, and then instead of maltose, the resulting molecule would be cellobiose.

Hanging on the direction of the bond attached to the hydroxyl group relative to the CH2OH substituent of the alike glucose ring, the anomeric carbon (C1) of the other glucose molecule, which is not intricate in a glycosidic bond, could be either an α- or β-anomer. Hence, it results in the formation of either β-maltose or α-maltose.

Isomaltose is an isomer of maltose, which is similar to maltose. But in isomaltose, α(1→4) bonding is replaced with α(1→6) linkage.

O-glycosidic linked maltose structure is given below:

Maltose Structure

Production of Maltose

The name maltose is derived from the word ‘malt’. The suffix ‘ose’ was added to describe that maltose belonged to the sugar category. The ‘ose’ represents the important biochemical series of glucose chains. It was named after malting, an example of this reaction found in germinating seeds.

It is formed from starch digestion by amylase. The preparation of maltose is done in the presence of the enzyme diastase by the hydrolysis of starch. Starch is heated for several minutes with a strong acid, breaking down to form two glucose molecules. With the help of the enzyme called maltase, it is converted to glucose. And this glucose is used for the process of living beings.

The maltose is also produced when two glucose units are removed at a time when beta-amylase breaks down starch.

Properties of maltose

Maltose is also a reducing sugar similar to glucose. The reason is that the two glucose units are connected so that when the ring is opened, one of the glucose units can acquire an aldehyde group. Due to the glycosidic bond’s character cannot be possible with the other glucose molecule unit.

  • The enzyme maltase can break down this glycosidic linkage. This enzyme catalyses the glycosidic bond hydrolysis steps. As a result, glucose units are formed.
  • Maltose demonstrates mutarotation in aqueous solutions; these two forms exist in equilibrium in aqueous solutions.
  • With the help of Fearon’s or Woehlk’s test on methylamine, you can detect maltose easily.
  • Depending upon the concentration, maltose is almost 30-60% as sweet as sugar. Also, a 10% maltose solution is 35% as sweet as sucrose.

Physical Properties of maltose:



Maltose Formula


Molecular Mass

342.297 g.mol-1


No odour


1.54 g.cm-3


Sweet taste, similar to sugar

Melting Point

160 – 165 °C

Heat Capacity

298.15 K

Solubility in Water

1.080 g/mL (at 20 °C)

Chiral Rotation

+140.7° [α]D

Chemical properties of maltose:

  • Maltose is a reducing sugar because one of its glucose units has a free aldehyde group.
  • It appears in the form of white powder or crystals.
  • When maltose is treated with sulphuric acid, carbon dioxide, water, and sulphur dioxide are obtained as the final products.

C12H22O11 + 24H2SO4 → 12CO2 + 35H2O + 24SO2

  • On hydrolysis of maltose, the formation of ethanol and carbon dioxide takes place.

C12H22O11 + H2O → 4C2H5OH + 4CO2

  • In the presence of the maltase enzyme, maltose hydrolysis into glucose. Maltase acts as a catalyst during this reaction.

C12H22O11 + H2O → 2C12H22O11

Sources and Assimilation of maltose

  • Maltose is a component of ‘malt.’ It is a substance procured by transforming a cereal grain into a malted grain. It is possible to convert the grain into sprout by soaking it in water. After that, the halting germination process is dried with hot air. This way, the enzymes are developed, breaking down starches and proteins in the grain.
  • Maltose is a partially hydrolysed starch product similar to corn syrup, maltodextrin, and acid-thinned starch.
  • It is broken down by various maltase enzymes in the human body, providing two glucose molecule units. These glucose molecules can further break down and supply energy or can be stored as glycogen.
  • Due to the lack of the sucrase-isomaltase enzyme, sucrose intolerance is caused in humans. But as there are four various maltase enzymes, complete maltose bias is extremely rare.
  • Fruits are another general source of maltose in the diet, especially pears and peaches.

Uses of maltose

  • Most syrups get their pleasingness from maltose.
  • Excessive-maltose corn syrup gives 50% or more of its sugar in the conformation of maltose.
  • For making beer, maltose is used in the barley’s malting process, which adds sweetness to the beer.
  • It is beneficial in making hard candies and an affordable sweetener.
  • Its caramel-like taste is used in bakeries, soft drinks, sweets, alcoholic drinks, and infant food. It is also added to sugar-free products.
  • During the germination of seeds, maltose is synthesised by an enzyme called amylase, which hydrolyses starch to disaccharide for the new plants.
  • Starch is partially transformed into maltose by amylase during digestion, and maltase secreted by the intestine converts maltose into glucose. This glucose is either utilised by the body or stored in the liver as glycogen.
  • Maltose is harmful if consumed in excess. It leads to diabetes, obesity, and heart disease.


To conclude, what is a maltose? It is a disaccharide sugar composed of two glucose molecules connected with an alpha 1,4 glycosidic bond. It is a reducing-sugar. It is an intermediate product of starch hydrolysis and does not appear to exist freely in nature.

Besides many uses, maltose has an elevated glycemic index and can source greater blood glucose stakes than sucrose.

Frequently Asked Questions

1. What is the importance of maltose?

Although maltose is not an essential nutrient, it has a lot of importance in life.

  • In plants, it is formed when starch is broken down during food.
  • Maltose and its digestive product glucose attract water from the intestinal wall because of the osmotic effect. As a result, it can cause diarrhoea if consumed in excess.
  • In the small intestinal lining, maltose is broken down into two glucose units with the help of maltase and isomaltase enzymes.
  • Maltose can help in promoting dental caries.

2. What is the waste product of maltose?

Maltose breaks down into carbon dioxide and alcohol during fermentation. During digestion, maltase is in charge of metabolising maltose and converting it into two α-glucose molecules. Later on, to get energy, the body utilises these glucose molecules.

3. What occurs if maltose goes through hydrolysis?

Maltose is a type of disaccharide carbohydrate. Hence, what is maltose made of is by linking two glucose molecule units. These two glucose modules are in the pyranose form and are connected by an O-glycosidic bond. In this type of bonding, the first carbon (C1) of the first glucose is joined to the second glucose’s fourth carbon (C4). It is indicated as (1→4) linkage.

The products formed after hydrolysis of maltose are two D-glucose units.

Maltose Hydrolysis

4. Is replacing table sugar with maltose a better option?

Maltose does not accommodate fructose as sucrose or table sugar does. Hence, exchanging sucrose with maltose in your foodstuff will aid you in avoiding the familiar health suggestions of too much table sugar. However, the effects of maltose on health have not been studied well. Therefore, it is healthier to consult with a dietitian before replacing it in your diet.

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