What is the Difference Between Maltose Lactose and Sucrose

The main difference between maltose lactose and sucrose is that maltose is a disaccharide molecule composed of two glucose molecules linked together, lactose is a disaccharide composed of a glucose molecule and a galactose molecule, while sucrose is a disaccharide made up of glucose and a fructose molecule.

Maltose, fructose, and sucrose are types of sugars with different chemical compositions and sources.

Key Areas Covered

1. What is Maltose 
      – Definition, Digestion, Uses
2. What is Lactose 
      – Definition, Digestion, Uses
3. What is Sucrose
      – Definition, Digestion, Uses
4. Similarities Between Maltose Lactose and Sucrose
      – Outline of Common Features
5. Difference Between Maltose Lactose and Sucrose
      – Comparison of Key Differences

Key Terms

Maltose, Lactose, Sucrose

What is Maltose

Maltose is a disaccharide composed of two glucose molecules linked together through an alpha-1,4-glycosidic bond. The chemical formula of maltose is C₁₂H₂₂O₁₁. Its molar mass is 342.1162 g/mol, and its density is 1.54 g/cm³.

Maltose is commonly present in germinating grains, mainly in barley. During the malting process, starch in barley grains breaks down into maltose by amylase. This is helpful in the production of malt beverages like beer, where maltose serves as the primary source of fermentable sugar. Maltose can also be present in smaller quantities in other grains, such as wheat and rice.

Properties of maltose include maltose being a reducing sugar. It tastes sweet, but it is only 30-60 percent sweet as sugar. Compared to other sugars, maltose is less sweet. It possesses a subtle sweetness with a slightly malty flavor which explains its use in malt-based products. The modest sweetness of maltose allows for a balanced taste profile in food and beverages which makes it a valuable component in certain recipes.

Furthermore, the hydrolysis reaction of maltose with an acid catalyst gives two molecules of alpha D glucose. In addition, maltose gives a positive test with Benedicts and Tollens reagents.

Uses of Maltose

Maltose is utilized as an energy source. In the presence of maltase, maltose breaks down into its constituents, glucose molecules, which can then be absorbed into the bloodstream and used by cells for energy production. Most individuals possess sufficient amounts of maltase to digest maltose effectively.

Furthermore, there are industrial uses of maltose. It is mostly made use of in the food and beverage industry. It is also useful in the brewing and fermentation processes. Maltose is a primary sugar in beer production. During the mashing phase of brewing, enzymes convert starches in malted grains into fermentable sugars, mainly maltose. Yeast then consumes these sugars to produce alcohol and carbon dioxide resulting in the creation of beer’s characteristic flavors and carbonation.

Maltose is also useful in the production of malted beverages like malted milkshakes and malted hot drinks. It also acts as a food additive to provide sweetness, enhance texture, and act as a natural preservative in certain products.

What is Lactose

Lactose is a disaccharide composed of two sugar molecules, glucose and galactose, linked by a beta-1,4-glycosidic bond. Lactose is mostly present in mammalian milk and serves as the main carbohydrate in milk produced by mammals, including humans  Cow’s milk is the most common source of lactose. Milk from goats, sheep, and buffalo also contains lactose. For newborns and infants, lactose is an important source of energy. 

Lactase enzyme is required to digest lactose. The small intestine produces these enzymes. Lactase breaks down lactose into its constituents, glucose and galactose molecules, which allows their absorption into the bloodstream. Cells use them for energy production and various metabolic processes.

Uses of Lactose

Lactose is used in the food industry as an ingredient in a wide range of products. It contributes to the taste, texture, and browning properties of baked goods, acting as a natural sweetener and providing a source of fermentable sugar in the production of fermented foods like yogurt and cheese. In pharmaceutical companies, lactose helps as an excipient or filer in the production of medications, particularly in tablet and capsule formulations.

What is Sucrose

Sucrose is a disaccharide composed of two monosaccharides, glucose and fructose, linked together by an alpha-1,2 glycosidic bond. It is a crystalline substance with a sweet taste and is highly soluble in water. Sucrose is present in plant sources like sugarcane, sugar beets, and a wide range of fruits. Sugar cane and sugar beets are the primary commercial sources of sucrose production. By extraction and refining processes, pure sucrose is obtained in the form of granulated sugar or powdered sugar. Sucrose is also present in plants such as pineapples, oranges, and grapes.

Moreover, in the digestive system, sucrose breaks down into glucose and fructose molecules in the presence of the enzyme sucrase. Cells absorb glucose and fructose from the bloodstream to use as a source of energy.

Uses of Sucrose

Sucrose acts as a sweetener in the food and beverage industry. It is useful in the production of baked goods, confectionery, desserts, sauces, beverages, and preserved foods. In addition, in the pharmaceutical industry, it acts as an inactive ingredient, which helps in the stability of tablets and syrups.

Similarities Between Maltose Lactose and Sucrose

• Maltose, lactose, and sucrose are all sugars.
• Moreover, they serve as energy sources.
• All are disaccharides.

Difference Between Maltose Lactose and Sucrose

Definition

Maltose is a disaccharide molecule composed of two glucose molecules linked together, while lactose is a disaccharide composed of a glucose molecule and a galactose molecule, and sucrose is a disaccharide made up of glucose and a fructose molecule.

Natural Sources

While maltose is present in germinating grains like barley, lactose is present mainly in sugar in mammalian milk and cow’s milk, and sucrose is present in sugar cane, sugar beets, and fruits like pineapples, oranges, and grapes.

Digestion

Maltose is broken down into glucose molecules by the enzyme maltase; lactose is broken down into glucose and galactose by lactase, while sucrose is broken down into glucose and fructose by the sucrase enzyme.

Uses

Maltose is used in brewing and fermentation processes, contributing to the production of beer and other malt-based beverages. Lactose is used in dairy products, baked goods, and pharmaceutical formulations, while sucrose is used in food and beverage products.

Conclusion

In brief, maltose, fructose, and sucrose are types of sugars with different chemical compositions and sources. The main difference between maltose, lactose, and sucrose is that maltose is a disaccharide molecule composed of two glucose molecules linked together, while lactose is a disaccharide composed of a glucose molecule and a galactose molecule, and sucrose is a disaccharide made up of glucose and a fructose molecule.

Reference:

1. “Maltose Structure.” Byju’s.
2. “Lactose intolerance.” NHS Website.
3. “What is Sucrose?” Food Insight.

Image Courtesy:

1. “Sucrose structure formula” By Bas – with Inkscape (CC BY-SA 3.0) via Commons Wikimedia
2. “Formation du lactose” By Belgarath007 – Own work (CC BY-SA 3.0) via Commons Wikimedia
3. “Maltose cyclic horizontal” By Physchim62 – Own work (CC BY 3.0) via Commons Wikimedia