Everyone has experienced this. Cutting onions is a tearful experience, it brings tears to your eyes and a runny nose. Have you ever wondered why this happens?
The culprit behind this phenomenon lies in a compound known as sulfenic acid, a fascinating component found in onions.
Let’s know more about them in this post,
Acids Present in Onion
Onions are sulfur-rich vegetables and hence contain sulfenic acid along with other Quercetin flavanols.
Onions contain a variety of compounds, and one of the key players in the tear-inducing drama is sulfenic acid. This acid is part of a group called sulfenic acids, specifically amino acid sulphoxides.
Research shows Onion contains large quantities of carboxylic acids such as citric acid 48.5%, malic acid 43.6%, tartaric acid 18.8% and oxalic acid 11.3%
When the skin of an onion is broken, enzymes and sulfenic acid compounds combine to produce propanethyl S-oxide, a gas that makes your eyes water. You can destroy the enzymes by freezing or cooking the onion.
The Chemistry of Tears: Sulfenic Acids and Volatile Gas
Sulfenic acid in onions is inherently unstable. When you cut or chop an onion, you rupture its cells, releasing these sulfenic acids. What happens next is truly intriguing.
Upon their release, sulfenic acids decompose into a volatile gas. This gas wafts through the air, eventually reaching your eyes. The magic—or rather, the tearful tragedy—occurs when this gas reacts with the water in your eyes, forming a dilute solution of sulfuric acid.
The Eye’s Reaction to Sulphuric Acid
Sulfuric acid, even in its diluted form, can be irritating to the eyes. It stimulates the eyes to produce tears as a defense mechanism, attempting to wash away the irritant. This natural reaction is what leads to watery eyes and the sensation of crying when chopping onions.
Quick Tip: To minimize onion-induced tears, try chilling the onions before chopping or using a sharp knife, as it helps reduce the amount of cell damage and subsequent release of sulfenic acids.
By employing a few tricks, you can make the onion-chopping experience less tearful.
- Chill Before You Chop: Place onions in the refrigerator before cutting. This slows down the release of sulfenic acids.
- Sharpen Your Knife: A sharp knife minimizes cell damage, reducing the amount of sulfenic acids released.
- Cut Under Running Water: Chopping onions under running water helps disperse the volatile gas, minimizing its contact with your eyes.
So, the next time you find yourself tearing up while preparing a meal, remember that it’s not just the onions playing with your emotions; it’s the intricate chemistry of sulfenic acids and their journey to become a fleeting, tearful presence in your kitchen.
Share your thoughts and let’s dive deeper into the intriguing world of everyday science! 🧅🔬
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