Cornstarch and modified cornstarch are both derived from corn. However, they have some key differences in terms of their structure, properties, and uses.
In a nutshell, cornstarch is extracted from the endosperm of corn kernels. It consists almost entirely of starch. Modified cornstarch has undergone a chemical or enzymatic process that alters the starch molecules. This changes the starch’s properties, making it better suited for certain applications.
Below we will explore cornstarch and modified cornstarch in more detail, looking at how they are made, their characteristics, and why one may be preferred over the other for different purposes. We will also summarize the key similarities and differences between the two.
What is cornstarch?
Cornstarch, sometimes referred to as cornflour, is a fine, powdery starch derived from the endosperm of corn kernels.
To produce cornstarch, corn kernels are first soaked and then separated into their germ, fiber, and endosperm components. The endosperm contains most of the kernel’s starch and protein content. It is then processed to extract the starch in powder form, leaving behind the protein content.
Pure cornstarch contains around 27% amylose and 73% amylopectin. Amylose and amylopectin are the two types of starch molecules:
- Amylose has a linear structure and tends to form strong gels.
- Amylopectin has a branched structure and gives a creamy texture.
The ratio of amylose to amylopectin affects the properties of the starch. Cornstarch has relatively more amylopectin compared to other starches, giving it a soft and fine texture.
Unmodified cornstarch forms opaque gels and gives a cloudy appearance. It has a neutral taste and white color. Some key characteristics of cornstarch include:
- Thickening agent: Cornstarch can absorb water and swell, increasing the viscosity of liquids.
- Non-sticky: Does not form viscous pastes like some other starches.
- Freeze-thaw stable: Can withstand multiple freeze-thaw cycles with minimal changes.
- Semi-clear gels: Forms gels that are not completely transparent.
Due to its gelling and thickening properties, cornstarch has many culinary and industrial uses including:
- Thickener for sauces, gravies, puddings, custards
- Coating for fried foods
- Binder and adhesive in paper goods, textiles, etc.
- Component of bioplastics
- Powdered glove ingredient to absorb sweat
What is modified cornstarch?
Modified cornstarch refers to cornstarch that has been chemically or enzymatically treated to alter its molecular structure. This changes the starch’s properties and improves its functionality for certain applications.
There are several ways corn starch can be modified:
- Cross-linking – Starch chains are linked together to prevent over-swelling and breakdown when heated. Improves texture and stability.
- Stabilization – Phosphate groups are added to prevent retrogradation (starch molecules re-aligning after cooling). Maintains gel properties.
- Substitution – Hydroxypropyl and acetyl groups are used to alter gel formation. Changes viscosity and freeze-thaw stability.
- Conversion – Acid hydrolysis is used to reduce molecular size. Lowers gelatinization temperature and viscosity.
- Octenylsuccinylation – Octenyl succinic anhydride is added to make the starch more hydrophobic. Improves emulsification.
The specific modifications made depend on the desired end-use properties. Some common varieties of modified cornstarches include:
- Pregelatinized starch – Gelatinized then dried to hydrate quickly in cold water.
- Acid-modified starch – Hydrolyzed with acid to reduce viscosity and improve shelf-stability.
- Hydroxypropyl starch – Hydroxypropyl groups improve freeze-thaw stability and transparency.
- Cross-linked starch – Cross-linking prevents over-swelling when heated or frozen.
Modified starches typically have improved stability under high temperatures, shear, acidity and freezing compared to native starch. Key characteristics include:
- Stable viscosity in acidic foods like fruit fillings.
- Withstand freezing and thawing with minimal weeping or syneresis.
- Clear, cohesive gels vs. opaque gels formed by cornstarch.
- Heat-resistant and shear-stable thickening.
Due to their enhanced functional properties, modified starches are used in many processed foods and industrial applications:
- Thickener in canned soups, frozen foods, bakery fillings
- Improves moisture retention and shelf-life of baked goods
- Adhesive pastes for corrugated board
- Textile warp sizing
- Binding agent for tablets and capsules
Similarities between cornstarch and modified cornstarch
Despite some differences in properties and uses, cornstarch and modified cornstarch share some key similarities:
- Both derived from corn kernel endosperm.
- Contain a mixture of amylose and amylopectin starch molecules.
- Can be used as food thickeners and stabilizers.
- Offer a neutral taste and white color.
- Form gels, though modified starch gels tend to be more stable.
- Offer a smooth mouthfeel.
Key differences between cornstarch and modified cornstarch
There are some notable ways in which cornstarch and modified cornstarch differ:
| Characteristic | Cornstarch | Modified Cornstarch |
|---|---|---|
| Structure | Native starch molecules | Chemically/enzymatically altered starch molecules |
| Stability | Less stable to heat, shear, acid, freezing | More stable to heat, shear, acid, freezing |
| Clarity | Forms opaque, semi-clear gels | Can form very clear, transparent gels |
| Viscosity | Neutral to moderately high viscosity | Wide range of viscosity depending on modification |
| Common Uses | Thickener for sauces, gravies, puddings | Thickener for processed foods, adhesive pastes, textile sizing |
Which is better?
It is difficult to say definitively whether cornstarch or modified cornstarch is “better” overall. Each has advantages and disadvantages that make them suitable for different applications.
Unmodified cornstarch offers a clean label and simple ingredient. It works well in cooking applications where extreme conditions are not needed. Modified starches can withstand more processing and extremes of temperature, acidity, shear etc. This makes them preferable for shelf-stable and frozen foods.
In many products, both types of starch are used together to utilize the benefits of each. Cornstarch may provide the base starch, while modified starch is added to enhance properties like moisture retention, freeze-thaw stability, and shelf life.
Cost is another consideration. Unmodified corn starch is generally cheaper than modified starches. However, modified starches may allow the use of less total starch to achieve the same effect.
Ultimately, the goals of the specific product should guide the choice of cornstarch, modified cornstarch, or a combination of both. Manufacturers need to consider factors like processing conditions, shelf life, and budget to select the appropriate starch ingredients.
Modified cornstarch varieties
There are numerous specific modified cornstarch ingredients used in food production. Some examples include:
Pregelatinized starch
Pregelatinized starch has been cooked and then dried so it can hydrate in cold water without heat. It provides an instant thickening effect and smooth texture. Common uses include instant puddings, salad dressings, and cream-based soups.
Acid-modified starch
Acid-hydrolysis is used to reduce the molecular size of starch. Acid-modified starches have low viscosity and are stable in acidic foods like fruit fillings and yogurt.
Hydroxypropyl starch
Hydroxypropyl substitution improves moisture retention and freeze-thaw stability. Hydroxypropyl starches are used in frozen foods, baked goods, instant foods.
Cross-linked starch
Cross-linking makes starch more resistant to breakdown from heat, shear, and acids. Cross-linked starches provide stable thickening in canned foods, soups, and fruit pie fillings.
Waxy maize starch
Waxy maize starch contains over 98% amylopectin. It produces very smooth, short textured gels for use in foods like puddings, gravies, cream soups, and salad dressings.
Resistant starch
Resistant starch is not broken down in the small intestine so it acts like soluble fiber. It is used to boost the fiber content and lower the glycemic index of foods like baked goods, pasta, and smoothies.
Octenylsuccinated (OSA) starch
The addition of hydrophobic octenyl succinic groups improves starch’s ability to act as an emulsifier. OSA starches can stabilize emulsions like salad dressings, peanut butter, and chocolate.
How to choose the right one
Choosing the appropriate cornstarch or modified starch comes down to understanding the properties you need for your specific food product and manufacturing processes. Here are some tips:
– Consider the neutral flavor and clean label benefits of regular cornstarch vs. modified options.
– Determine the temperature, acidity, shear conditions the starch will need to withstand during production and shelf life.
– Evaluate the viscosity, gel texture, and clarity needed in the finished product.
– Modified starches can improve moisture retention, freeze-thaw stability, and emulsification.
– Pregelatinized starch instantly thickens without heat but costs more than regular cornstarch.
– Understand regulatory compliance – some modified starches need special labeling.
– Request starch samples from suppliers to test performance under your specific requirements.
– Work with knowledgeable starch suppliers who can help determine the ideal starch or starch blend.
Testing different starches during product development is key to finding the right match for your production processes and final product quality.
Using cornstarch vs. modified starch in recipes
When using cornstarch or modified starches in home recipes, keep these tips in mind:
- Follow recipe instructions carefully as starches vary in thickening power.
- Cornstarch thickens at lower temperatures compared to flour. It can thin out if overheated.
- Whisk slurries of cornstarch with cool water before adding to dishes to prevent clumping.
- Modified food starches may withstand higher heat without breaking down.
- Start with half the modified starch called for until you know its thickening power.
- Pregelatinized starch can thicken instantly without cooking.
- Acid-modified starches create smoother fillings for fruit pies.
- Add starches at the end of cooking as flavor develops during heating.
With some experimentation, you can discover when to use cornstarch, pregel starch, or other modified starches to get the best results in your recipes.
Conclusion
While cornstarch and modified cornstarch come from the same source, their characteristics and uses can differ significantly. Unmodified cornstarch offers a clean label thickener and stable neutral flavor. Modified starches provide enhanced properties like stability in freezing, heat, acid, and shear for processed food production.
Understanding the strengths of each type of starch enables food manufacturers to select the right one or the ideal blend to create high quality products. Product developers can work with knowledgeable starch suppliers to determine the proper starch ingredients for their specific processing needs and final product characteristics.
