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Blue Onions Explained – Why They Appear And Can You Eat Them?

Blue Onions Explained – Why They Appear And Can You Eat Them?

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Onions are a staple in many kitchens. They are used for cooking, as well as for flavoring dishes. Onions come in a variety of colors, but the most common is the white onion.

There are many different varieties of onions, but the most common ones are yellow, red, and white. It is related to garlic, leeks, chives, and shallots. There are no blue onions here, but why?

The color of onion is determined by the presence of sulfur compounds and their concentration. The more sulfur compounds present, the darker the onion will be. The color can also be affected by how long it has been stored and how it was grown.

This article is here to tell you all about blue onions and why their pigment changes.

Blue Onions Myth: Is There Such Thing As A Blue Onion?

red onions on rustic wood

The color of onions is determined by the variety of onions and the soil in which they are grown. The most common colors are white, yellow onion, and red. There is no such thing as a blue onion.

Onions and regular food can turn blue, but there are no naturally blue onions. A blue onion has not been identified yet, but we do know that the onion is a vegetable that has been found to have many health benefits.

There are many plants that produce blue flowers and some of them even produce blue fruits, but there is no plant that produces a blue onion.

The blue onion is a type of onion that has a bluish to bright blue color. It is not a real type of onion but rather an artificial dye that is used to turn regular onions blue. It is not clear if the blue onion is actually a vegetable or just an artificial dye.

Why Do Onions Turn Blue?

onion cut on a wooden board

Onions turn blue due to anthocyanin pigments changing color when in contact with alkaline pH. In fact, this is only a color change, and nothing else changes in the onion.

In other words, your reddish-purple onion was in contact with lemon juice, orange juice, lentils, or other food items with low pH, which made them turn a blue-green color.

Anthocyanins are a type of plant pigment that helps many plants produce a red color. Recent studies have found that there are several health benefits to anthocyanins, and they’re relatively sensitive to changes in pH.

The color under these conditions changes to a blue tone, which is a result of the color molecules absorbing more energy from photons. 

To get the purest form of anthocyanins, you’re best off with acidic foods. However, if you cook red onion in alkaline materials like nut milk or lentil soup or some other alkaline veggies, it will turn that red color to blue.

Onions turn blue when they are exposed to the air. This is because the onion’s cells are full of sulfur compounds. When these compounds come into contact with oxygen, they react and form a blue pigment called thiosulfate.

The color of onion can also be affected by how it is stored. If an onion is stored in a cool, dark place, it will turn purple or brown because the sulfur compounds will not react with oxygen as quickly.

Why Does Garlic And Onion Turn Blue?

When garlic and onion are cut, the cells in the plant tissue break down, releasing a substance called alliin. Alliin is converted to allicin when it comes into contact with air. Allicin is what gives garlic and onion their characteristic flavor.

The blue color of these vegetables comes from a compound called allicin, which is produced when two molecules of hydrogen sulfide react with an enzyme called alliinase.

The enzyme then splits the molecule into two pieces that eventually combine to form a compound called diallyl sulfide (DAS).

Onions turn blue because of a chemical called anthocyanin, which is present in the papillae. Anthocyanin is also found in blueberries and red cabbage. It helps with the absorption of light and gives off a distinctive blue color.

The sulfur in onions reacts with oxygen and water to form hydrogen sulfide gas, which then combines with anthocyanin to produce the familiar shade of blue.

Do Onions Turn Blue In The Fridge?

the woman takes out an onion from the refrigerator

Yes, onions do change color in the fridge and eventually turn blue. You can alter the color of the cooked red onion by refrigerating it, but it will return to reddish-purple color when you warm it up again.

There are many myths about the color of onions. Some people believe that onions turn blue in the fridge, but this is not always true.

The reason why onions turn blue is that they contain a pigment called anthocyanin, which is responsible for the deep purple color of the onion.

Anthocyanin can react with oxygen and water molecules to produce hydrogen peroxide and higher or lower the pH scale and eventually turns into an insoluble compound called metmyoglobin which is blue-colored.

Onions turn brown when they are exposed to light and oxygen. They also turn brown when they are cut or bruised.

Onions are a type of vegetable that is red when raw and turns brown when cooked. This is because the green pigment chlorophyll changes to the red pigment carotenoid when onions are cooked.

Why Does Garlic Turn Blue In Vinegar?

Garlic turns blue in vinegar because of the reaction between sulfur and iron. This is nothing more than a color change, the onions can be eaten after they have turned blue.

The reaction between sulfur and iron produces a compound called sulfurous acid, which is responsible for turning garlic blue. The color change is due to the oxidation process that occurs when garlic is exposed to air.

A reaction between sulfur and iron creates a blue-green color. When garlic is submerged in vinegar, the sulfur becomes dissolved in the acid and turns it into this color.

Many people and especially cooking beginners, have noticed the blue color of garlic, but few know what actually causes it. Sulfur produces a compound called sulfurous acid, which is responsible for turning garlic blue.

How To Prevent Garlic From Turning Blue?

You can prevent garlic from turning blue. The basic food hack to prevent garlic and onions from turning blue is to keep them away from the fridge, vinegar, and blanche them before fermenting.

The best way to prevent this from happening is to cook the garlic in an oven or microwave for 30 minutes at 200 degrees Fahrenheit. You could also blanche the allium before you start to ferment or cook them.

Another way to prevent this from happening, you should store your garlic in an airtight container with a lid that has an opening of less than 1/4 inch. You should also keep the container away from light and heat sources.

You might have seen the following question in a cooking forum or on social media: How to prevent garlic from turning blue?

Garlic is an ingredient that has many uses. It can be used in recipes, it can be eaten raw, and it can even preserve your breath for hours. However, it’s a challenge to keep garlic fresh for any length of time.

Can You Eat Blue Onions?

a woman cuts an onion

Yes, you can eat blue onions. Blue onions don’t look as good, but you can eat them without consequences.

If you’ve ever wondered if it was okay to eat blue onions, the answer is yes, you can. Blue onions tend to be a little less attractive than regular onions, but they are just as tasty.

They also have great health benefits, so if you’re curious about trying them out but don’t want to take the risk of looking like a weirdo at your next barbecue, it’s definitely worth it.

You can safely consume your food after you’ve mixed it in alkaline water, as it will not affect the flavor in any way whatsoever. The change in color is natural and should not be perceived as a negative attribute.

The color of blue onions comes from anthocyanins, which are a type of flavonoid that gives fruits and vegetables their colors.

Is It Safe To Eat Onions That Have Turned Green?

The answer to this question is yes, you can eat cooked onions that have turned green unless they have gone bad.

The green color of the onion is a result of a chemical reaction that causes the onion to release sulfenic acid, which turns the onions green. This chemical reaction can be reversed by adding baking soda or vinegar.

It is safe to eat onions that have turned green because they are not unsafe for human consumption. This happens when the sulfur compounds in the onion react with oxygen in the air and turn into sulfenic acid.

It may indicate that the onion has been exposed to too much light, but it is still complete even despite the green coloration. If you want to get rid of the vegetation, then let it sit in a dark closet or just cut off the green parts.

This vegetable is harvested from the ground and has many uses, including being used as a cooking ingredient. There are wide varieties of onions that range in color from white to deep purple.

Why Do Red Onions Turn Blue?

Onions are one of the most preferred vegetables in the world. They are available in a variety of colors and shapes. The most common type is white onion, which is also known as yellow onion. Other popular types of onions include red onion, green onion, brown onion, and purple onion.I hope you now know why blue onions appear. It’s not a disease. It’s just the lemon juice or other alkaline foods getting in contact with them. The same goes for red cabbage, purple carrots, purple cauliflower, shiraz grapes, and others.

Blue Onions Explained - Why They Appear And Can You Eat Them