Does Amylase Break Down Starch or Maltose? Understanding Carbohydrate Digestion

November 18, 2025 •

2 min read

The average adult processes pounds of carbohydrates each day, but few understand the enzymes involved in breaking them down. So, does amylase break down starch or maltose, or both? The answer reveals a two-step digestive process crucial for converting complex carbohydrates into usable energy.

Quick Summary

Amylase initiates the digestion of complex starch, breaking it down into smaller sugar molecules, predominantly the disaccharide maltose. It does not break down maltose itself; another enzyme, maltase, is responsible for that final step of converting maltose into glucose.

Key Points

Amylase Breaks Down Starch: The enzyme amylase targets and breaks the long chains of starch molecules, which are complex carbohydrates.
Amylase Produces Maltose: As amylase breaks down starch, it primarily yields maltose, a smaller disaccharide, as an intermediate product.
Amylase Does Not Break Down Maltose: Due to enzyme specificity, amylase cannot act on the maltose molecules it creates.
Maltase Breaks Down Maltose: A different enzyme, maltase, takes over to break down the maltose into two simple glucose molecules.
Digestion is a Two-Step Process: The complete digestion of starch into usable glucose requires the sequential action of both amylase and maltase.
Carbohydrate Breakdown is Sequential: The digestive process starts with amylase in the mouth and small intestine, followed by maltase in the small intestine for the final conversion to glucose.

The Role of Amylase in Starch Digestion

Amylase is a vital digestive enzyme primarily responsible for the initial breakdown of starch, a complex carbohydrate (polysaccharide). Produced in the salivary glands and pancreas, amylase starts the process in the mouth and continues it in the small intestine. It works by hydrolyzing the alpha-1,4 glycosidic bonds within the starch molecule, breaking the long chains of glucose units into smaller fragments. The main products of amylase activity are smaller carbohydrates, including maltotriose and maltose, a disaccharide made of two glucose units. Amylase is specific to starch and does not act on the maltose it produces.

The Specificity of Enzyme Action

Enzymes like amylase exhibit high specificity, acting on particular substrates due to their unique molecular structures. Amylase binds to starch to break specific bonds, but the resulting maltose molecule does not fit the enzyme's active site in a way that allows for further breakdown. This necessitates another enzyme for the next stage of digestion.

Maltase: The Final Act of Carbohydrate Digestion

After amylase breaks down starch into maltose, the enzyme maltase takes over to complete the digestion of maltose. Maltase is produced by the lining of the small intestine and specifically breaks the bond in maltose, yielding two individual glucose molecules. Glucose, being a simple sugar (monosaccharide), is then readily absorbed into the bloodstream for energy.

A Two-Stage Process: Starch to Glucose

The digestion of starchy foods exemplifies this two-step enzymatic process. Salivary amylase begins converting starch to maltose while chewing. In the small intestine, pancreatic amylase continues this process, and then maltase breaks down the maltose into absorbable glucose.

The Importance of Complete Carbohydrate Breakdown

The sequential action of amylase and maltase is crucial for efficient nutrient absorption and energy production. Deficiencies in these enzymes can lead to malabsorption and digestive issues.

Amylase vs. Maltase: A Comparison

The distinct roles of amylase and maltase are highlighted below.


Feature	Amylase (Alpha-Amylase)	Maltase
Substrate	Starch	Maltose
Primary Product	Maltose and other smaller chains	Glucose
Location	Salivary glands, pancreas	Small intestine lining
Mechanism	Hydrolyzes alpha-1,4 bonds in starch	Hydrolyzes the bond in maltose
Digestive Role	Initial breakdown of complex carbs	Final breakdown of disaccharides

Conclusion: A Collaborative Digestive Effort

Amylase primarily breaks down starch into smaller units, mainly maltose. It does not break down maltose itself. This role is performed by maltase, which converts maltose into glucose, the form our bodies can absorb. The combined action of amylase and maltase demonstrates a precise digestive process essential for converting complex carbohydrates into usable energy.

For additional information on carbohydrate metabolism, refer to resources from the National Institutes of Health (NIH).

Frequently Asked Questions

Starch is a complex carbohydrate (polysaccharide) made of long chains of glucose units. Maltose is a simpler sugar (disaccharide) composed of just two glucose units linked together.

Amylase is produced in the salivary glands, where digestion begins, and in the pancreas, which releases it into the small intestine to continue the process.

The final absorbable end product of starch digestion is glucose, which is produced when maltase breaks down maltose in the small intestine.

A deficiency in amylase would hinder the initial breakdown of starches into maltose, leading to undigested carbohydrates entering the large intestine. This can cause digestive issues like diarrhea.

This is due to salivary amylase. As you chew, the amylase in your saliva begins to break down the starch in the bread into maltose, a type of sugar, which your taste buds can detect.

The highly acidic environment of the stomach denatures and deactivates salivary amylase, effectively halting starch digestion temporarily until the food moves to the small intestine.

Yes, plants also produce amylase, particularly in germinating seeds, to break down stored starch into sugars for energy to fuel growth.