How to Extract Glucose from Sugar: The Science of Hydrolysis

December 13, 2025 •

4 min read

Sucrose, or common table sugar, is a disaccharide composed of one glucose and one fructose molecule. Learning how to extract glucose from sugar involves understanding the process of hydrolysis, a chemical reaction that can be initiated with simple acids or specific enzymes.

Quick Summary

The process involves using hydrolysis to break down sucrose into its constituent monosaccharides, glucose and fructose. This can be achieved through acidic or enzymatic methods, with complex purification needed to isolate pure glucose.

Key Points

Hydrolysis is the Key Process: To extract glucose, the disaccharide sucrose must be broken down by adding water, a process called hydrolysis.
Acidic vs. Enzymatic Methods: Hydrolysis can be catalyzed by acids (like lemon juice) or enzymes (like invertase).
Invert Sugar Production: Both acidic and enzymatic hydrolysis of sucrose yield an equimolar mixture of glucose and fructose, commonly known as invert sugar.
Separation is Complex: Separating pure glucose from the fructose in the resulting mixture is challenging and requires advanced techniques like crystallization with alcohol or industrial chromatography.
Industrial Production from Starch: On a commercial scale, glucose syrup is primarily produced from the hydrolysis of starch (e.g., cornstarch), which is more efficient and cost-effective than using sucrose.
Purity Depends on Method: Home methods produce a glucose-fructose syrup, while high-purity glucose extraction requires laboratory-specific separation techniques.

The Fundamental Chemistry: Breaking Down Sucrose

Table sugar, chemically known as sucrose ($C{12}H{22}O_{11}$), is a complex carbohydrate classified as a disaccharide. Its molecular structure consists of one glucose molecule and one fructose molecule linked together by a glycosidic bond. To extract glucose from sugar, this bond must be broken, and the chemical process to achieve this is called hydrolysis, which means "to split with water". The overall reaction is represented as:

$C{12}H{22}O_{11} + H_2O \rightarrow C6H{12}O_6 \text{ (Glucose)} + C6H{12}O_6 \text{ (Fructose)}$

This reaction can be catalyzed by an acid, an enzyme, or simply heat over a long period. The challenge, particularly for home-based extraction, is that this process yields an equimolar mixture of both glucose and fructose, which are isomers with identical chemical formulas but different structures. The resulting mixture is often called invert sugar. Separating the two monosaccharides to obtain pure glucose is significantly more complex.

Acid-Catalyzed Hydrolysis (The Laboratory/Home Method)

For a laboratory setting or a simple demonstration, acid hydrolysis is a straightforward method for breaking down sucrose.

Step-by-Step Procedure for Acid Hydrolysis

Prepare the solution: Dissolve a measured amount of sucrose in water to create a concentrated sugar solution.
Add the catalyst: Introduce a small amount of a dilute acid, such as hydrochloric acid (HCl) or sulfuric acid ($H_2SO_4$). For a safer, at-home version, a weak food-grade acid like lemon juice or cream of tartar is used.
Apply heat: Gently heat the solution to a controlled temperature, as this accelerates the hydrolysis reaction. The heat helps the acid effectively break the glycosidic bonds.
Monitor the reaction: Allow the mixture to react for the required time, typically a couple of hours for the laboratory method. At home, this is until the desired syrup consistency is achieved.
Neutralize the acid: Once hydrolysis is complete, the solution must be neutralized to make it safe for consumption (if applicable). This is typically done by adding a base, such as sodium bicarbonate (baking soda).

Important Considerations for Home Experimentation

Purity: This method does not separate the glucose from the fructose, so the final product will be an invert sugar syrup, not pure crystalline glucose.
Side reactions: Overheating can cause the sugars to caramelize, altering the flavor and color of the final product.
Safety: Always handle acids with care. Using a mild, food-safe acid for home experiments is strongly recommended.

Enzymatic Hydrolysis for Higher Purity

Invertase, also known as sucrase, is an enzyme that specifically catalyzes the hydrolysis of sucrose into glucose and fructose. This method is preferred in food production because it operates under milder conditions, preserving the quality of the sugar.

How Enzymatic Hydrolysis Works

Prepare the solution: A sugar solution is created similar to the acidic method.
Add the enzyme: The enzyme invertase is introduced into the solution.
Incubation: The mixture is incubated at a controlled temperature, typically around 37°C (98.6°F), allowing the enzyme to efficiently catalyze the reaction over several hours.

Separation and Purification Techniques

After hydrolysis, separating glucose from fructose is the next major challenge, especially if pure glucose is the goal. For the laboratory preparation from sucrose, alcohol is often added to the cooled solution. Glucose is less soluble in alcohol than fructose and will crystallize out first. The solution can then be filtered to collect the glucose crystals. However, complete separation is difficult to achieve perfectly.

For high-purity industrial applications, far more sophisticated methods are employed. Techniques like liquid chromatography (LC) and nanofiltration are used to separate the monosaccharides based on differences in their properties, though this is a complex and costly process. Most commercially produced glucose (in the form of corn syrup) is actually derived from the hydrolysis of starch, a more efficient industrial process.

Comparison of Hydrolysis Methods


Feature	Acidic Hydrolysis	Enzymatic Hydrolysis
Catalyst	Dilute acid (HCl, H2SO4, lemon juice)	Enzyme (Invertase/Sucrase)
Temperature	Elevated (accelerates reaction)	Controlled, milder (around 37°C)
Conditions	Requires neutralization of acid	Occurs under mild, specific conditions
Purity Control	Lower. Can lead to side reactions	Higher. Specific and controlled reaction
Scalability	Less efficient for large-scale pure glucose production	Preferred for large-scale food production
Yield	Equimolar mix of glucose and fructose	Equimolar mix of glucose and fructose

Conclusion: The Road to Pure Glucose

While it is chemically feasible to extract glucose from sugar (sucrose) through hydrolysis, the resulting product is a mix of glucose and fructose. Simple acid-catalyzed hydrolysis is a method that can be performed in a lab or at home to create invert sugar. For the isolation of pure glucose, more advanced separation techniques are required, and the process becomes significantly more complex. On an industrial scale, glucose production primarily utilizes starch hydrolysis, a more economical and efficient method for generating large quantities of pure glucose syrup. Understanding the different methods and their limitations provides a comprehensive overview of how this fundamental biological and chemical process is leveraged in everything from cooking to commercial manufacturing.

For more information on the industrial process of making glucose syrup from starch, see the process details from Myande Group.

Frequently Asked Questions

No, it is not possible to get pure glucose with a simple home process. Breaking down sucrose with heat and acid produces a syrup that is a mix of both glucose and fructose. Separating them requires advanced laboratory techniques.

The chemical reaction of hydrolyzing sucrose (table sugar) results in an equimolar mixture of glucose and fructose, both simple sugars or monosaccharides.

Lemon juice contains citric acid, which acts as a catalyst to speed up the hydrolysis reaction that breaks down sucrose. It also helps to prevent the resulting invert sugar from crystallizing.

The syrup made at home by breaking down sucrose is actually invert sugar. It is not chemically identical to commercial glucose syrup, which is usually made from starch and purified to contain predominantly glucose.

Hydrolysis is a chemical process that uses water to break down a larger molecule into smaller, simpler molecules. In this case, it breaks the glycosidic bond in sucrose.

Glucose and fructose have very similar physical and chemical properties, making it hard to isolate them through simple methods. While they have different solubilities in alcohol, a clean and complete separation is not easily achieved.

Industrially, glucose syrup is most often produced from the hydrolysis of starch (like corn or potatoes) using a series of enzymes. This process is more efficient and cost-effective for large-scale production.