What is Cornstarch?

Cornstarch is a fine, white, powdery substance that comes from the endosperm of corn (maize) kernels. The endosperm makes up most of the corn kernel and gives energy to the growing seedling. People in the United States call it corn starch, while in the United Kingdom it’s known as cornflour. Manufacturers extract it through wet milling, which breaks down corn kernels into their basic parts.

The molecular makeup of cornstarch has two main glucose polymers: amylose and amylopectin. Amylose makes up 20-30% of the starch and has straight glucose chains. Amylopectin accounts for 70-80% and has a complex branched structure. These molecules give cornstarch its special properties. When you add heat and water, the starch granules expand and release amylose to create a gel-like texture.

Cornstarch is different from corn flour in important ways. They both come from corn, but cornstarch goes through more refining. The process removes protein and fiber from the corn kernel, leaving just the starchy endosperm. Cornstarch is almost 100% starch with no fiber, protein, fat or other components. That’s why it has almost no taste and only adds texture to food.

Pure starch means no protein, so cornstarch naturally contains no gluten. The product packs lots of carbohydrates but lacks vitamins, protein, fiber, and minerals. Among all corn components, it ranks as one of the least nutritious.

Cornstarch shines in its role as a thickener. Heat it in water, and the starch granules swell up as they soak in moisture. They grow bigger and trap most of the free water, which turns the mixture into a paste-like consistency. Chefs love this property and use it to thicken their sauces, soups, gravies, and puddings.

Cornstarch does more than just help in cooking. It plays a key role in making corn syrup and other sugars. On top of that, it helps industries of all sizes – from paper making to textile production and even in making adhesives. Drug companies use it too, as it helps tablets and capsules break down better.

Mix cornstarch with liquids and you’ll see some fascinating behavior. It can become a non-Newtonian fluid – add water and you get oobleck, add oil and it turns into an electrorheological fluid.

How is Cornstarch Used?

Cornstarch does much more than just help in the kitchen. You can find this amazing ingredient in many industries because of its special properties.

Culinary uses

Cornstarch works best as a thickening agent in cooking. The magic happens at approximately 203°F (95°C) when its molecular chains spread out and bump into each other. They create a mesh that thickens liquids. This process is called starch gelatinization, and it creates clear rather than cloudy mixtures. That’s why many cooks prefer it to flour.

Here’s how cornstarch makes food better:

• Thickening: You’ll find it in sauces, gravies, soups, puddings, and pie fillings
• Crispness: It gives fried foods their crispy coating
• Tenderizing: Your baked goods become softer because it stops gluten from developing too much
• Anti-caking: It keeps powdered sugar and shredded cheese from getting clumpy

The best way to use cornstarch is to mix it with cold liquid before adding it to anything hot. This stops it from forming lumps. Just remember not to boil it too long – the sauce might get thin again.

Non-culinary uses

Cornstarch plays a key role in many industrial products. Paper makers use it to bind materials and finish surfaces. The textile industry adds it to size fabrics and make them stiffer.

You can use cornstarch at home to:

Clean grease stains, windows, and polish silverware. Mix it with water to make a great cleaning paste. It even helps you untangle knots in strings, shoelaces, or hair by making the strands slide past each other more easily.

Beauty companies put cornstarch in natural powders, masks, and talcum powders to reduce shine. You can make your own dry shampoo or deodorant with cornstarch as the main ingredient.

Medical uses

Pharmaceutical companies use cornstarch to bind and break down medicines. It helps tablets and capsules split into tiny pieces so your body can absorb the drugs better. That’s why you’ll find it in many medications like acetaminophen, hydrocodone, and oxycodone.

Cornstarch helps maintain blood glucose levels if you have glycogen storage disease. Babies can start taking it between 6-12 months old to keep their glucose levels steady.

The FDA lists cornstarch as a safe food substance (GRAS). In spite of that, it’s mostly just carbs without much nutritional value.

How is Cornstarch Made?

Wet milling technology separates corn kernels into their four main components: starch, germ, fiber, and protein to produce cornstarch. This industrial process creates highly purified starch through several stages.

Steeping and separation

Manufacturing starts when workers clean #2 yellow dent corn to remove cobs, dirt, chaff, and foreign materials. Clean kernels then soak in large stainless steel tanks with warm water (approximately 50°C) mixed with 0.1% sulfur dioxide for 30-40 hours. The corn kernels absorb water during this time and double in size as their moisture content rises from 15% to 45%. Controlled fermentation softens the kernel structure while mild acidity loosens the gluten bonds that release starch. The sulfur dioxide helps control bacterial growth and promotes beneficial lactobacillus activity.

Wet milling process

The softened kernels move to coarse grinding for component separation. Attrition mills break up the corn to free the germ from the endosperm and loosen the hull. Hydrocyclones separate the oil-rich germ from the slurry due to its lower density. These germs contain about 85% of the corn’s oil and need repeated washing on screens to remove leftover starch.

The degerminated slurry goes through fine grinding where impact or attrition mills release starch and gluten from the fiber. Fixed concave screens catch fiber while letting starch and gluten flow through. Workers wash the captured fiber to recover remaining starch before sending it to animal feed production.

Centrifugal separators process the starch-gluten suspension (mill starch) to separate lighter gluten from heavier starch. The starch still contains 1-2% protein at this point[131]. Extensive washing—usually 8 to 14 times—and additional purification in hydroclones brings the starch to more than 99.5% purity[124].

Drying and packaging

Specialized peeler centrifuges or rotary drum filters remove excess water from the purified starch slurry. The starch cake then enters the drying phase. Flash dryers designed specifically for starch process the dewatered starch. Moderate inlet air temperature protects the starch properties during drying. The finished cornstarch reaches 12-13% moisture content before moving pneumatically to silos. Final screening happens before commercial packaging. The product sells as unmodified cornstarch or undergoes further processing into modified starches, corn syrups and glucose.

Types of Cornstarch

Cornstarch types differ in their molecular makeup, modification status, and how they function. These characteristics determine how well they work in industries of all types.

Unmodified corn starch

Natural corn starch comes straight from corn endosperm without extra processing. Standard corn starch has 25-28% amylose and 72-75% amylopectin. This makeup creates a starch that thickens food well when cooked, though pastes with more than 4-5% solids become too thick to work with. The starch’s gels turn opaque and set faster when cool, which limits their use in stability-focused applications. Its neutral taste and thickening properties make it perfect for food products that need consistent texture.

Modified starches

Modified starches go through physical, enzymatic, or chemical treatments to boost their performance. Physical changes include heat-moisture treatments that change the granular structure without chemicals. Chemical modifications create derivatives with specific E-numbers (E1400-E1500) through acid-treating, crosslinking, or acetylation. These changes help the starch resist heat, acid, shear, cooling, and freezing better. Enzymatic modifications use natural enzymes to break down starch molecules in specific ways, which improves digestion and adjusts thickness. These starches last longer on shelves, handle freezing better, and offer specific texture properties.

Dextrins and derivatives

Dextrins come from heating or roasting plain starch with tiny amounts of acid or alkaline catalysts. They’re known for being less thick and dissolving better in cold water (5% to over 90%), and come in three main types. White dextrins look like the original corn starch and make light-colored pastes that form soft gels. Yellow dextrins need less acid but more heat to make. They create thick pastes (40-60%) that dry faster. British gums use minimal acid and longer roasting times. They have a tan to light brown color and smell like caramel.

Waxy vs high-amylose starch

Waxy corn starch contains almost 100% amylopectin and barely any amylose (0-8%), which gives it unique properties. Its pastes stay clear when cool, don’t congeal easily, and create see-through, water-soluble coatings. On top of that, it stays thick, handles cold temperatures well, and doesn’t break down during freezing and thawing. High-amylose corn starch has 50-80% amylose and needs higher heat (>120°C) to gel. You can find commercial types like amylomaize V (50%), VII (70%), and VIII (80%), with some reaching 90% amylose. These starches resist digestion, which makes them great for dietary fiber, keeping emulsions stable, and delivering drugs.

Is Cornstarch Safe?

Cornstarch has many common uses, but it comes with several safety risks that need attention in industrial, medical, and culinary settings.

Dust explosion risk

Cornstarch powder can explode as a fine dust and might trigger dust explosions under certain conditions. These explosions happen when five elements come together: flammable material (cornstarch), oxygen, proper dispersion, confinement, and an ignition source. The historical impact of cornstarch explosions has been devastating. A 1919 explosion in Cedar Rapids, Iowa killed 44 people and destroyed part of the town. European industries face dust explosions almost daily. Safety measures include equipment grounding to reduce static electricity, proper filtration systems, and careful monitoring of dust buildup.

Inhalation concerns

Breathing in cornstarch powder can cause breathing problems, especially if you have smaller airways. Studies show that exposure to cornstarch creates inflammation in airways with eosinophilic granulocyte buildup. Research on healthy people exposed to cornstarch powder revealed dust levels of 5.9 mg·m−3 total and 0.62 mg·m−3 respirable dust. Severe cases of cornstarch inhalation have led to life-threatening conditions that required breathing support. People might experience wheezing, quick breathing, shallow breaths, and chest pain.

Food safety

The FDA recognizes cornstarch as generally safe (GRAS) to eat. While safe in small amounts, you should never eat it raw. Blood sugar levels rise quickly after eating cornstarch due to its high glycemic index. This becomes especially important if you have diabetes. Good hygiene and proper food handling help prevent any foodborne illness from cornstarch products. Cornstarch offers few nutritional benefits and contains mostly carbohydrates without significant nutrients, but remains safe to eat when cooked properly.

Cornstarch vs Other Starches

Starches play unique roles in both cooking and industrial uses. Their distinct properties help determine the best way to use them.

Cornstarch vs flour

Cornstarch and flour work quite differently as thickening agents. Cornstarch comes purely from corn endosperm [link_1], while all-purpose flour brings gluten, protein, and wheat starch to the mix. You’ll need just half a tablespoon of cornstarch to create a silky sauce in under a minute – flour takes much more time and quantity. The rule of thumb says you should use twice as much flour as cornstarch. Your sauce will look different too – cornstarch creates clear, glossy results, but flour leaves things more opaque and matte. Flour packs more nutrients per 100g with higher protein (10.9g), calcium (19mg), iron (5.62mg), and magnesium (26.7mg) than cornstarch.

Cornstarch vs arrowroot

These gluten-free thickeners each shine in their own way. Arrowroot makes fruit dishes and pies look better with its clearer, glossier finish. Cornstarch tends to cloud things up a bit. The good news is neither will change your dish’s taste. Timing matters with arrowroot – add it last since heat breaks down its starch molecules. Cornstarch handles heat better but will eventually break down too. Arrowroot works great with acidic ingredients like lemon juice or vinegar, while cornstarch might struggle. Your frozen dishes will thank you for using arrowroot since it thaws beautifully, unlike cornstarch.

Starch vs cornstarch

Each starch variety brings something special to the kitchen. Potato starch thickens faster than cornstarch because it reacts at lower temperatures. Mac and cheese loves potato starch, but long cooking times aren’t its friend. Dairy dishes work best with cornstarch, while acidic foods prefer potato starch. Tapioca starch creates that perfect stringy texture you want in fruit pies. You might prefer arrowroot as a less processed option if you have digestion concerns. Root starches make dishes look silky and glossy but work best as last-minute additions.

FAQs

1. What are some common mistakes when using cornstarch? 

A common mistake is mixing cornstarch with hot water, which causes clumping. Always use cold water to create a smooth slurry before adding it to hot dishes for even thickening.

2. What are the key properties of cornstarch? 

Cornstarch is a fine, white powder derived from corn kernels. It’s primarily used as a thickening agent in various food products, capable of imparting desired rheological properties to sauces, soups, custards, and gravies.

3. How does cornstarch affect food texture? 

Cornstarch significantly impacts food texture. In baked goods like cookies, it creates a soft and chewy texture by softening flour proteins. When used in sauces or gravies, it provides a smooth, silky consistency.

4. How does cornstarch compare to other thickeners? 

Cornstarch is more efficient than flour for thickening, requiring smaller quantities. It creates clearer, glossier sauces compared to flour but is less clear than arrowroot. Unlike some starches, cornstarch can withstand higher cooking temperatures.

5. Is cornstarch safe to use? 

Cornstarch is generally recognized as safe (GRAS) by the FDA for consumption when properly cooked. However, it poses inhalation risks and has explosive properties as a fine dust. It’s also high in carbohydrates, which may affect blood sugar levels.